COPPER ALLOY

Abstract

A copper alloy according to the present invention includes 17 mass % to 34 mass % of Zn, 0.02 mass % to 2.0 mass % of Sn, 1.5 mass % to 5 mass % of Ni, and a balance consisting of Cu and unavoidable impurities, in which relationships of 12f1=[Zn]+5[Sn]2[Ni]30, 10[Zn]0.3[Sn]2[Ni]28, 10f3={f1(32f1)[Ni]}.sup.1/233, 1.200.7[Ni]+[Sn]4, and 1.4[Ni]/[Sn]90 are satisfied, conductivity is 13% IACS to 25% IACS, a ratio of an phase is 99.5% or more by area ratio or an area ratio of a phase ()% and an area ratio of a phase ()% in an phase matrix satisfy a relationship of 02()+()0.7.

Claims

1-12. (canceled)

13. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content expressed in mass %, [Zn], a Sn content expressed in mass %, [Sn], and a Ni content expressed in mass %, [Ni], satisfy relationships of
12f130, wherein f1=[Zn]+5[Sn]2[Ni],
10f228, wherein f2=[Zn]0.3[Sn]2[Ni],
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, the copper alloy has a metallographic structure, selected from the group consisting of (1) a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio, and (2) an area ratio of a phase ()% and an area ratio of a phase ()% dispersed in an phase matrix, satisfy a relationship of 02()+()0.7, the phase having an area ratio of 0% to 0.3% and the p phase having an area ratio of 0% to 0.5% in the phase matrix.

14. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; at least one or more selected from 0.003 mass % to 0.09 mass % of P, 0.005 mass % to 0.5 mass % of Al, 0.01 mass % to 0.09 mass % of Sb, 0.01 mass % to 0.09 mass % of As, and 0.0005 mass % to 0.03 mass % of Pb; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content in mass %, [Zn], a Sn content in mass %, [Sn], and a Ni content in mass %, [Ni] satisfy relationships of
12f130, wherein f1=[Zn]+533 [Sn]2[Ni],
10f228, wherein f2=[Zn]0.3[Sn]2[Ni], and
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; wherein the Sn content in mass %, [Sn],and the Ni content in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, in a metallographic structure, a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio or an area ratio of a phase ()% and an area ratio of a phase ()% of an phase matrix satisfy a relationship of 02()+()0.7, and the phase having an area ratio of 0% to 0.3% and the p phase having an area ratio of 0% to 0.5% are dispersed in the phase matrix, wherein, the copper alloy contains P as at least one or more selected elements, the Ni content expressed in mass %, [Ni] and a P content expressed in mass %, [P] satisfy a relationship of
25[Ni]/[P]750.

15. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; 0.0005 mass % or more and 0.2 mass % or less in total of at least one or more selected from Fe, Co, Mg, Mn, Ti, Zr, Cr, Si and rare earth metal elements, each contained in an amount of 0.0005 mass % or more and 0.05 mass % or less; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content expressed in mass %, [Zn], a Sn content expressed in mass %, [Sn], and a Ni content expressed in mass %, [Ni], satisfy relationships of
12f130, wherein f1=[Zn]+5[Sn]2[Ni],
10f228, wherein f2=[Zn]0.333 [Sn]2[Ni], and
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, the copper alloy has a metallographic structure, selected from the group consisting of (1) a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio, and (2) an area ratio of a phase ()% and an area ratio of a phase ()% dispersed in an phase matrix and satisfy a relationship of 02()+()0.7, the phase having an area ratio of 0% to 0.3% and the phase having an area ratio of 0% to 0.5% in the phase matrix.

16. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; at least one or more selected from 0.003 mass % to 0.09 mass % of P, 0.005 mass % to 0.5 mass % of Al, 0.01 mass % to 0.09 mass % of Sb, 0.01 mass % to 0.09 mass % of As, and 0.0005 mass % to 0.03 mass % of Pb; 0.0005 mass % or more and 0.2 mass % or less in total of at least one or more selected from Fe, Co, Mg, Mn, Ti, Zr, Cr, Si and rare earth metal elements, each contained in an amount of 0.0005 mass % or more and 0.05 mass % or less; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content expressed in mass %, [Zn], a Sn content expressed in mass %, [Sn], and a Ni content expressed in mass %, [Ni],satisfy relationships of
12f130, wherein f1=[Zn]+5[Sn]2[Ni],
10f228, wherein f2=[Zn]0.3[Sn]233 [Ni], and
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, the copper alloy has a metallographic structure, selected from the group consisting of (1) a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio, and (2) an area ratio of a phase ()% and an area ratio of a phase ()% dispersed in an phase matrix and satisfying a relationship of 02()+()0.7, the phase having an area ratio of 0% to 0.3% and the p phase having an area ratio of 0% to 0.5% in the phase matrix, wherein, when the copper alloy contains P as at least one or more selected elements, the Ni content in mass %, [Ni], and a P content in mass %, [P], satisfy a relationship of
25[Ni]/[P]750.

17. The copper alloy according to claim 13, wherein the copper alloy is applicable to medical appliances, handrails, door handles, and water supply and drain sanitary facilities, apparatuses and containers.

18. The copper alloy according to claim 13, wherein the copper alloy is used for electronic and electrical components and automobile components of connectors, terminals, relays, and switches.

19. The copper alloy according to claim 14, wherein the copper alloy is applicable to medical appliances, handrails, door handles, and water supply and drain sanitary facilities, apparatuses and containers.

20. The copper alloy according to claim 15, wherein the copper alloy is applicable to medical appliances, handrails, door handles, and water supply and drain sanitary facilities, apparatuses and containers.

21. The copper alloy according to claim 16, wherein the copper alloy is applicable to medical appliances, handrails, door handles, and water supply and drain sanitary facilities, apparatuses and containers.

22. The copper alloy according to claim 14, wherein the copper alloy is used for electronic and electrical components and automobile components of connectors, terminals, relays, and switches.

23. The copper alloy according to claim 15, wherein the copper alloy is used for electronic and electrical components and automobile components of connectors, terminals, relays, and switches.

24. The copper alloy according to claim 16, wherein the copper alloy is used for electronic and electrical components and automobile components of connectors, terminals, relays, and switches.

25. The copper alloy according to claim 13, wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.60.7[Ni]+[Sn]4, and
1.8[Ni]/[Sn]12, and wherein the conductivity is 13% IACS or more and 21% IACS or less.

26. The copper alloy according to claim 14, wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.60.7[Ni]+[Sn]4, and
1.8[Ni]/[Sn]12, and wherein the conductivity is 13% IACS or more and 21% IACS or less.

27. The copper alloy according to claim 15, wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni],satisfy relationships of
1.60.7[Ni]+[Sn]4, and
1.8[Ni]/[Sn]12, and wherein the conductivity is 13% IACS or more and 21% IACS or less.

28. The copper alloy according to claim 16, wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.60.7[Ni]+[Sn]4, and
1.8[Ni]/[Sn]12, and wherein the conductivity is 13% IACS or more and 21% IACS or less.

29. The copper alloy according to claim 13, wherein the content of Ni is 2.1 mass % to 5 mass %, wherein the conductivity is 13% IACS or more and 25% IACS or less, wherein the Zn content expressed in mass %, [Zn], the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
12f129, wherein f1=[Zn]+5[Sn]2[Ni],
10f227, wherein f2=[Zn]0.3[Sn]2[Ni], and
12f333, wherein f3={f1(32f1)[Ni]}.sup.1/2, and wherein the Sn content expressed in mass % [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.40.7[Ni]+[Sn]4, and
1.6[Ni]/[Sn]90.

30. The copper alloy according to claim 14: wherein the copper alloy further includes 0.003 mass % to 0.09 mass % of P.

31. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; 0.0005 mass % to 0.05 mass % of Fe; optionally 0.0005 mass % or more and 0.2 mass % or less in total of one or more selected from Co, Mg, Mn, Ti, Zr, Cr, Si and rare earth metal elements, each contained in an amount of 0.0005 mass % or more and 0.05 mass % or less; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content expressed in mass %, [Zn], a Sn content expressed in mass %, [Sn], and a Ni content expressed in mass %, [Ni], satisfy relationships of
12f130, wherein f1=[Zn]+5[Sn]2[Ni],
10f228, wherein f2=[Zn]0.3[Sn]2[Ni], and
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, the copper alloy has a metallographic structure, selected from the group consisting of (1) a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio, and (2) an area ratio of a phase ()% and an area ratio of a phase ()% dispersed in an phase matrix satisfy a relationship of 02()+()0.7, and the phase having an area ratio of 0% to 0.3% and the phase having an area ratio of 0% to 0.5% in the phase matrix.

32. A copper alloy comprising: 17 mass % to 34 mass % of Zn; 0.02 mass % to 2.0 mass % of Sn; 2.1 mass % to 5 mass % of Ni; 0.003 mass % to 0.09 mass % of P; 0.0005 mass % to 0.05 mass % of Fe; optionally one or more selected from 0.005 mass % to 0.5 mass % of Al, 0.01 mass % to 0.09 mass % of Sb, 0.01 mass % to 0.09 mass % of As, and 0.0005 mass % to 0.03 mass % of Pb; optionally 0.0005 mass % or more and 0.2 mass % or less in total of one or more selected from Co, Mg, Mn, Ti, Zr, Cr, Si and rare earth metal elements, each contained in an amount of 0.0005 mass % or more and 0.05 mass % or less; and a balance consisting of Cu and unavoidable impurities, wherein a Zn content expressed in mass %, [Zn], a Sn content expressed in mass %, [Sn], and a Ni content expressed in mass %, [Ni], satisfy relationships of
12f130, wherein f1=[Zn]+5[Sn]2[Ni],
10f228, wherein f2=[Zn]0.3[Sn]2[Ni], and
10f333, wherein f3={f1(32f1)[Ni]}.sup.1/2; wherein the Sn content expressed in mass %, [Sn], and the Ni content expressed in mass %, [Ni], satisfy relationships of
1.20.7[Ni]+[Sn]4, and
1.4[Ni]/[Sn]90, wherein a conductivity is 13% IACS or more and 25% IACS or less, and wherein, the copper alloy has a metallographic structure, selected from the group consisting of (1) a ratio of an phase in a constituent phase of the metallographic structure is 99.5% or more by area ratio, and (2) an area ratio of a phase ()% and an area ratio of a phase ()% dispersed in an phase matrix satisfy a relationship of 02()+()0.7, and the phase having an area ratio of 0% to 0.3% and the phase having an area ratio of 0% to 0.5% in the phase matrix, wherein the Ni content expressed in mass %, [Ni], and a P content expressed in mass %, [P], satisfy a relationship of
25[Ni]/[P]750.

33. The copper alloy according to claim 13: wherein proof stress80%(100%stress relaxation rate (%) at 150 C. for 1,000 hours) is 295 N/mm.sup.2 or more.

34. The copper alloy according to claim 14: wherein proof stress80%(100%stress relaxation rate (%) at 150 C. for 1,000 hours) is 295 N/mm.sup.2 or more.

35. The copper alloy according to claim 15: wherein proof stress80%(100%-stress relaxation rate (%) at 150 C. for 1,000 hours) is 295 N/mm.sup.2 or more.

36. The copper alloy according to claim 16: wherein proof stress80%(100%stress relaxation rate (%) at 150 C. for 1,000 hours) is 295 N/mm.sup.2 or more.

Description

EXAMPLES

[0139] Hereinafter, the results of confirmation tests that were carried out to confirm the effects of the present invention will be shown. The following examples are shown to describe the effects of the present invention and configurations, processes, and conditions described in the examples do not limit the technical scope of the present invention.

[0140] Samples were prepared by using the above-described copper alloys according to the first to sixth embodiments of the present invention and copper alloys having configurations for comparison and changing production processes. The compositions of the copper alloys are shown in Tables 1 to 4. In addition, production processes are shown in Table 5. In Tables 1 to 4, composition relational expressions f1, f2, f3, f4, f5 and f6 shown in the above-described embodiment are shown.

TABLE-US-00001 TABLE 1 Alloy Component composition (mass %) Composition relational expression No. Zn Ni Sn P Other elements Cu f1 f2 f3 f4 f5 f6 1 27.2 2.9 0.52 Balance 24.0 21.2 24 2.6 5.6 2 23.7 3.8 1.00 Balance 21.1 15.8 30 3.7 3.8 3 30.3 3.4 0.64 0.02 Balance 26.7 23.3 22 3.0 5.3 170 4 25.9 2.3 0.55 0.04 Balance 24.1 21.1 21 2.2 4.2 58 5 19.9 1.8 0.80 0.01 Balance 20.3 16.1 21 2.1 2.3 180 6 27.8 2.7 0.44 0.02 As Balance 24.6 22.3 22 2.3 6.1 135 0.03 7 28.7 3.4 0.51 Sb Balance 24.5 21.7 25 2.9 6.7 0.04 8 30.8 2.4 0.68 0.02 Balance 29.4 25.8 14 2.4 3.5 120 11 32.7 2.6 0.34 Balance 29.2 27.4 15 2.2 7.6 12 30.3 1.8 0.56 0.02 Balance 29.5 26.5 12 1.8 3.2 90 13 26.2 1.7 1.10 0.02 Balance 28.3 22.5 13 2.3 1.5 85 14 31.2 2.4 0.39 0.04 Balance 28.4 26.3 16 2.1 6.2 60 15 30.6 2.5 0.56 Balance 28.4 25.4 16 2.3 4.5 16 27.5 1.9 0.42 0.05 Balance 25.8 23.6 17 1.8 4.5 38 17 27.6 3.5 0.75 Balance 24.4 20.4 26 3.2 4.7 18 25.8 2.0 0.46 0.005 Balance 24.1 21.7 20 1.9 4.3 400 19 26.2 3.1 0.68 Balance 23.4 19.8 25 2.9 4.6 20 26.2 1.6 0.17 0.02 Balance 23.9 22.9 18 1.3 9.4 80 21 20.6 4.0 1.00 Balance 17.6 12.3 32 3.8 4.0 22 21.8 3.2 0.60 0.06 Balance 18.4 15.2 28 2.8 5.3 53

TABLE-US-00002 TABLE 2 Alloy Component composition (mass %) Composition relational expression No. Zn Ni Sn P Other elements Cu f1 f2 f3 f4 f5 f6 23 21.5 2.7 0.56 Balance 18.9 15.9 26 2.5 4.8 24 22.2 1.9 0.45 Balance 20.7 18.3 21 1.8 4.2 25 24.4 3.5 1.20 Balance 23.4 17.0 27 3.7 2.9 26 18.5 3.0 0.95 Balance 17.3 12.2 28 3.1 3.2 27 25.8 2.5 0.71 0.03 Sb Balance 24.4 20.6 22 2.5 3.5 83 0.04 28 27.0 2.2 0.48 0.02 Fe Balance 25.0 22.5 20 2.0 4.6 110 0.0009 29 28.2 2.6 0.46 0.008 Fe Balance 25.3 22.9 21 2.3 5.7 325 0.009 30 26.5 2.4 0.56 0.02 Co Balance 24.5 21.5 21 2.2 4.3 120 0.003 31 27.5 3.0 0.55 Fe Balance 24.3 21.3 24 2.7 5.5 0.02 32 29.0 3.4 0.47 Al Balance 24.6 22.1 25 2.9 7.2 0.04 33 30.6 3.4 0.58 0.007 Mg Balance 26.7 23.6 22 3.0 5.9 486 0.02 34 27.5 2.5 0.42 0.02 Mn Balance 24.6 22.4 21 2.2 6.0 125 0.02 35 26.8 3.1 0.48 Ti Cr Balance 23.0 20.5 25 2.7 6.5 0.005 0.005 36 27.5 2.2 0.41 0.05 Zr Balance 25.2 23.0 19 2.0 5.4 44 0.008 37 29.0 3.3 0.46 Si Balance 24.7 22.3 24 2.8 7.2 0.03 38 28.7 3.4 0.70 0.008 Sb Balance 25.4 21.7 24 3.1 4.9 425 0.04 39 27.5 3.1 0.60 Sb As Balance 24.3 21.1 24 2.8 5.2 0.02 0.02 40 28.4 2.6 0.37 0.02 Pb Balance 25.1 23.1 21 2.2 7.0 130 0.007 41 24.4 3.9 1.00 As Balance 21.6 16.3 30 3.7 3.9 0.03 42 28.5 3.4 0.49 Ce Balance 24.2 21.6 25 2.9 6.9 0.01 43 24.2 2.3 0.04 0.03 Balance 19.8 19.6 24 1.7 57.5 77 44 25.4 1.9 1.00 0.07 Balance 26.6 21.3 17 2.3 1.9 27 45 26.1 3.0 0.65 0.005 Balance 23.4 19.9 25 2.8 4.6 600

TABLE-US-00003 TABLE 3 Alloy Component composition (mass %) Composition relational expression No. Zn Ni Sn P Other elements Cu f1 f2 f3 f4 f5 f6 101 30.7 2.3 0.91 Balance 30.7 25.8 10 2.5 2.5 102 29.9 1.6 0.75 0.02 Balance 30.5 26.5 9 1.9 2.1 80 103 30.1 1.2 0.42 0.02 Balance 29.8 27.6 9 1.3 2.9 60 104 27.4 0.86 0.52 0.02 Balance 28.3 25.5 10 1.1 1.7 43 105 34.5 3.8 0.56 0.03 Balance 29.7 26.7 16 3.2 6.8 127 106 34.6 4.3 0.75 Balance 29.8 25.8 17 3.8 5.7 107 22.9 2.5 2.00 Balance 27.9 17.3 17 3.8 1.3 108 29.4 1.6 0.45 0.12 Balance 28.5 26.1 13 1.6 3.6 13 109 29.1 1.6 0.97 0.02 Balance 30.8 25.6 8 2.1 1.6 80 110 31.9 2.3 0.64 Balance 30.5 27.1 10 2.3 3.6 111 26.9 1.5 0.09 Balance 24.4 23.9 17 1.1 16.7 112 31.8 1.6 0.22 0.04 Balance 29.7 28.5 10 1.3 7.3 40 113 32.5 3.4 1.00 Balance 30.7 25.4 12 3.4 3.4 114 24.2 1.7 1.40 Balance 27.8 20.4 14 2.6 1.2 115 32.0 1.8 0.30 Balance 29.9 28.3 11 1.6 6.0 116 33.2 2.9 0.71 0.05 Balance 31.0 27.2 10 2.7 4.1 58 117 31.9 2.2 0.78 Balance 31.4 27.3 6 2.3 2.8 118 28.1 1.7 1.20 Balance 30.7 24.3 8 2.4 1.4 119 16.1 2.0 0.36 Balance 13.9 12.0 22 1.8 5.6 120 27.2 2.3 0.69 0.03 Fe Balance 26.1 22.4 19 2.3 3.3 77 0.07 121 27.9 2.6 0.63 0.02 Co Balance 25.9 22.5 20 2.5 4.1 130 0.08 122 28.9 1.3 0.58 Balance 29.2 26.1 10 1.5 2.2 123 23.3 2.1 0.02 Balance 19.2 19.1 23 1.5 105.0 124 23.8 2.0 0.01 0.03 Balance 19.9 19.8 22 1.4 200.0 67 125 17.3 3.4 0.05 Balance 10.8 10.5 28 2.4 68.0 126 25.1 1.7 1.00 0.08 Balance 26.7 21.4 16 2.2 1.7 21

TABLE-US-00004 TABLE 4 Alloy Component composition (mass %) Composition relational expression No. Zn Ni Sn P Other elements Cu f1 f2 f3 f4 f5 f6 201 28.7 Balance 202 25.5 Balance 203 20.8 Balance 204 17.2 Balance 205 7.80 0.08 Balance

TABLE-US-00005 TABLE 5 Hot rolling + milling Rolling Annealing Rolling Annealing Process thickness thickness Temperature Time thickness Temperature No. (mm) (mm) ( C.) (min) (mm) ( C.) Time (min) A1-1 12 2.5 580 240 0.9 500 240 A1-2 12 2.5 580 240 0.9 500 240 A1-3 12 2.5 580 240 0.9 500 240 A1-4 12 2.5 580 240 0.9 500 240 A2-1 12 1.0 510 240 A2-2 12 1.0 510 240 A2-3 12 1.0 510 240 A2-4 12 1.0 510 240 A2-5 12 1.0 510 240 A2-6 12 1.0 510 240 A2-7 12 1.0 670 0.24 A2-8 12 1.0 670 0.24 A2-9 12 1.0 510 240 A2-10 12 1.0 670 0.24 A3-1 12 1.0 680 0.3 B1-1 6 0.9 510 240 B1-2 6 0.9 510 240 B1-3 6 0.9 510 240 B2-1 6 B3-1 (Annealing) 6 620 240 0.9 510 240 B3-2 (Annealing) 6 620 240 0.9 510 240 C1 6 0.9 510 240 C1A 6 0.9 510 240 C2 6 1.0 430 240 Rolling thickness Final Finish Recovery heat before annealing rolling treatment Process finish Temperature Time Thickness Re Temperature Time No. (mm) ( C.) (min) It1 (mm) (%) ( C.) (min) It2 A1-1 0.36 425 240 0.3 17 300 30 295 A1-2 0.36 425 240 0.3 17 450 0.05 338 A1-3 0.36 425 240 0.3 17 300 0.07 206 A1-4 0.36 690 0.14 610 0.3 17 450 0.05 338 A2-1 0.36 425 240 0.3 17 450 0.05 338 A2-2 0.36 670 0.09 570 0.3 17 450 0.05 338 A2-3 0.36 670 0.09 570 0.3 17 300 0.07 206 A2-4 0.36 670 0.09 570 0.3 17 A2-5 0.40 690 0.14 610 0.3 25 450 0.05 338 A2-6 0.40 690 0.14 610 0.3 25 250 0.15 185 A2-7 0.40 705 0.18 634 0.3 25 450 0.05 338 A2-8 0.40 770 0.25 710 0.3 25 450 0.05 338 A2-9 0.40 580 240 0.3 25 450 0.05 338 A2-10 0.36 620 0.05 486 0.3 17 450 0.05 338 A3-1 Seam welding pipe with 25.4 mm prepared after being slit having width of 86 mm B1-1 0.36 425 240 0.3 17 450 0.05 338 B1-2 0.36 670 0.09 570 0.3 17 300 0.07 206 B1-3 0.36 670 0.09 570 0.3 17 300 30 295 B2-1 0.36 425 240 0.3 17 300 30 295 B3-1 0.36 425 240 0.3 17 300 30 295 B3-2 0.36 670 0.09 570 0.3 17 300 30 295 C1 0.36 425 240 0.3 17 300 30 295 C1A 0.36 670 0.09 570 0.3 17 300 30 295 C2 0.40 380 240 0.3 25 230 30

[0141] In a production process A (A1-1 to A1-4, A2-1 to A2-10, and A3-1), raw materials were melted in an induction melting furnace having an internal volume of 5 tons and ingots having a cross section with a thickness of 190 mm and a width of 630 mm were produced by semi-continuous casting. The ingots each were cut to have a length of 1.5 m and then a hot rolling process (sheet thickness: 13 mm)a cooling processa milling process (sheet thickness: 12 mm)a cold rolling process were carried out.

[0142] The hot rolling start temperature in the hot rolling process was set to 820 C., the material was hot-rolled to a sheet thickness of 13 mm, and then cooled by shower water cooling in the cooling process. The average cooling rate in the cooling process was set to a cooling rate in a temperature range from when the temperature of the rolled material after final hot rolling, or the temperature of the rolled material reached 650 C. when the temperature reached 350 C. and was measured in the rear end of the rolled sheet. The measured average cooling rate was 3 C./sec.

[0143] In the processes A1-1 to A1-4, a cold rolling (sheet thickness: 2.5 mm)an annealing process (580 C., holding time: 4 hours)cold rolling (sheet thickness: 0.9 mm)an annealing process (500 C., holding time: 4 hours)a rolling process before finishing (sheet thickness: 0.36 mm and a cold working rate of 60%)a final annealing process (final recrystallization heat treatment process)a finish cold rolling process (sheet thickness of 0.3 mm and a cold working rate of 17%)a recovery heat treatment were carried out.

[0144] As the final annealing of the processes A1-1 to 3, batch annealing (425 C., holding time: 4 hours) was carried out. In the process A1-1, a recovery heat treatment was carried out under batch-type conditions (300 C., holding time: 30 minutes) in a laboratory. In the process A1-2, a recovery heat treatment was carried out by a continuous high temperature short time annealing method in a work line under the conditions of (450 C.0.05 minutes) when the maximum reaching temperature of the rolled material Tmax ( C.) and a holding time tm (min) in a range from a temperature 50 C. lower than the maximum reaching temperature of the rolled material to the maximum reaching temperature are expressed as (Tmax ( C.)tm (min or minutes)). In the recovery heat treatment of the process A1-3, a heat treatment, which will be described later, was carried out in a laboratory under the conditions of (300 C.0.07 min). In the process A1-4, final annealing was carried out under the conditions of (690 C.0.14 minutes) of a high temperature short time annealing method and (450 C.0.05 minutes) of a recovery heat treatment.

[0145] In the processes A2-1 to A2-10, an annealing process was carried out one time, and cold rolling (sheet thickness: 1 mm)an annealing process a rolling process before finishing (in the processes A2-1 to A2-4, and A2-10, sheet thickness: 0.36 mm, cold working rate: 64%, and in the processes A2-5 to A2-9, sheet thickness: 0.4 mm, cold working rate: 60%)a final annealing processa finish cold rolling process (in the processes A2-1 to A2-4 and A2-10, sheet thickness: 0.3 mm, cold working rate: 17%, and in the processes A2-5 to A2-9, sheet thickness: 0.3 mm, cold working rate: 25%)a recovery heat treatment were carried out.

[0146] The annealing process of the processes A2-1 to A2-6 and A2-9 was carried out under the conditions of (510 C., holding time: 4 hours) and the processes A2-7, A2-8 and A2-10 were carried out by a high temperature short time annealing method under the conditions of (670 C.0.24 minutes).

[0147] As the final annealing of the process A2-1, batch annealing (425 C., holding time: 4 hours) was carried out, the processes A2-2, 3 and 4 were carried out by a continuous high temperature short time annealing method (670 C.0.09 minutes), the processes A2-5 and A2-6 were carried out under the conditions of (690 C.0.14 minutes), the process A2-7 was carried out under the conditions of (705 C.0.18 minutes), the process A2-8 was carried out under the conditions of (770 C.0.25 minutes), the process A2-10 was carried out under the conditions of (620 C.0.05 minutes), and the process A2-9 was carried out under the conditions of batch annealing of (580 C., holding time: 4 hours).

[0148] In the continuous high temperature short time annealing method which has been carried out, when the temperature is 600 C. or the maximum reaching temperature is 600 C. or lower, the average cooling rate in a temperature range from the maximum reaching temperature to 350 C. was 3 C./second to 18 C./second although the average cooling rate differed depending on conditions.

[0149] The recovery heat treatment of the processes A2-1, 2, 5, and 7 to 10 was carried out under the conditions of continuous high temperature short time annealing of (450 C.0.05 minutes), the process A2-3 was carried out in a laboratory under the conditions of (300 C.0.07 min), and the process A2-6 was carried out in a laboratory under the conditions of (250 C.0.15 min). Regarding the process A2-4, the recovery heat treatment was not carried out.

[0150] The high temperature short time annealing was carried by a method of completely immersing the rolled material in 2-liter oil baths storing heat treating oils, which are classified into 3 kinds in JIS in JIS K 2242:2012, each heated to 300 C. and 250 C., for 0.07 minutes and 0.15 minutes, respectively, under the conditions of (300 C.0.07 min) or (250 C.0.15 min) as conditions corresponding to a molten Sn plating process, instead of the recovery heat treatment.

[0151] The process A3-1 was carried out by cold-rolling a milling material to 1 mm and carrying out a continuous high temperature short time annealing method under the conditions of (680 C.0.3 minutes) such that the average grain size was 10 m to 18 m. The coil was slit to have a width of 86 mm, and for production of a welded pipe, an intermediate material (annealed material of width 86 mmthickness 1 mm) was supplied at a feed rate of 60 m/min and was subjected to deformation processing into a circular shape by plural rolls. The cylindrical material was heated by a high-frequency induction heating coil and the both ends of the intermediate material were joined by lamination. A welded pipe having a diameter of 25.4 mm and a thickness of 1.08 mm was obtained by cutting and removing the bead portion of the joint portion by a cutting tool (cutting blade tool). Due to changes in thickness, when the welded pipe is formed, cold working of substantially several percents is carried out.

[0152] In addition, the production process B was carried out as follows using experimental facilities.

[0153] Ingots of the production process A were cut into ingots for a laboratory test which had a thickness of 30 mm, a width of 120 mm and a length of 190 mm. Then, the cut ingots were subjected to a hot rolling process (sheet thickness: 6 mm)a cooling process (air cooling)a pickling process a rolling processan annealing processa rolling process before finish (thickness: 0.36 mm)a recrystallization heat treatment process a finish cold rolling process (sheet thickness: 0.3 mm, working rate: 17%)a recovery heat treatment.

[0154] In the hot rolling process, each of the ingots was heated to 830 C. and the ingot was hot-rolled to a thickness of 6 mm. The cooling rate (cooling rate at the temperature of a rolled material after the hot rolling or in a temperature range from 650 C. to 350 C.) in the cooling process was mainly set to 5 C./second, and the surface of the rolled material was pickled after the cooling process.

[0155] In the processes B1-1 to B1-3, an annealing process was carried out one time, a material was cold-rolled to 0.9 mm in a rolling process, the annealing process was carried out under the conditions of (510 C., holding time: 4 hours), and the material was cold-rolled to 0.36 mm in a rolling process before finishing. Final annealing was carried out under the conditions of (425 C., holding time: 4 hours) in the process B1-1 and (670 C.0.09 minutes) in the processes B1-2 and B1-3, and the material was finish-rolled to 0.3 mm. Then, a recovery heat treatment was carried out under the conditions of (450 C.0.05 minutes) in the process B1-1, (300 C.0.07 min) in the process B1-2, and (300 C., holding time: 30 minutes) in the process B1-3.

[0156] In the process B2-1, an annealing process was omitted. A sheet material having a thickness of 6 mm after pickling was cold-rolled to 0.36 mm in the rolling process before finishing (working rate: 94%), final annealing was carried out under the conditions of (425 C., holding time: 4 hours), the material was finish-rolled to 0.3 mm, and further, a recovery heat treatment was carried out under the conditions of (300 C., holding time: 30 minutes).

[0157] In the processes B3-1 and B3-2, hot rolling was not carried out and cold rolling and annealing were repeatedly carried out. The ingot having a thickness of 30 mm was subjected to homogenization annealing at 720 C. for 4 hours, cold-rolled to 6 mm, subjected to an annealing process under the conditions of (620 C., holding time: 4 hours), cold-rolled to 0.9 mm, subjected to an annealing process under the conditions of (510 C., holding time: 4 hours), and cold-rolled to 0.36 mm. Final annealing was carried out under the conditions of (425 , holding time: 4 hours) in the process of B3-1 and (670 C.0.09 minutes) in the process of B3-2, the material was finish-cold-rolled to 0.3 mm, and then a recovery heat treatment was carried out under the conditions of (300 C., holding time: 30 minutes).

[0158] In the production process B, a process corresponding to a short-time heat treatment performed by a continuous annealing line or the like in the production process A was substituted with immersion of the rolled material in a salt bath. The maximum reaching temperature was set to a temperature of a liquid of the salt bath, the immersion time was set to the holding time, and air cooling was performed after immersion. In addition, a mixed material of BaCl, KCl, and NaCl was used as salt (solution).

[0159] Further, the process C (C1, C1A) as a laboratory test was carried out as follows. Melting and casting were carried out with an electric furnace in a laboratory to have predetermined components, whereby ingots for a test, which had a thickness of 30 mm, a width of 120 mm, and a length of 190 mm, were obtained. Then, production was carried out by the same processes as the above-described process B1-1. Each of the ingots was heated to 830 C. and hot-rolled to a thickness of 6 mm. After the hot rolling, the ingot was cooled at a cooling rate of 5 C./second at a temperature of the rolled material after the hot rolling or in a temperature range from 650 C. to 350 C. The surface of the rolled material was pickled after the cooling, and the rolled material was cold-rolled in the cold rolling process to 0.9 mm. After the cold rolling, the annealing process was carried out under conditions of 510 C. and 4 hours. In the following rolling process, the material was cold-rolled to 0.36 mm. Final annealing was carried out under the conditions of (425 C., holding time: 4 hours) in the process C1 and (670 C.0.09 minutes) in the process C1A, the material was cold-rolled to 0.3 mm (cold working rate: 17%) in the finish cold rolling, and a recovery heat treatment was carried out under the conditions of (300 C., holding time: 30 minutes).

[0160] The process C2 is a process of a material for comparison and due to the characteristics of the material, the thickness and heat treatment conditions were changed such that the final average grain size was 10 m or less and the tensile strength was about 500 N/mm.sup.2. After pickling, the material was cold-rolled to 1 mm, an annealing process was carried out under the conditions of 430 C. and 4 hours, and the material was cold-rolled to 0.4 mm in a rolling process. Final annealing conditions were a temperature of 380 C. and a holding time of 4 hours, the material was cold-rolled to 0.3 mm by finish cold rolling, (cold working rate: 25%), and a recovery heat treatment was carried out under the conditions of (230 C., holding time: 30 minutes).

[0161] Regarding phosphor bronze, a commercially available product of C5210 containing 8 mass % of Sn and having a tensile strength of about 640 N/mm.sup.2 and a thickness of 0.3 mm was prepared.

[0162] The metallographic structures of the copper alloys prepared in the above-described methods were observed, and the average grain size and the ratios of and phases were measured. In addition, the average particle size of precipitates was measured by TEM. Further, to evaluate the characteristics of the copper alloys, tests for conductivity, stress relaxation characteristics, stress corrosion cracking resistance, tensile strength, proof stress, elongation, bending workability, color fastness, and antimicrobial properties were carried out for measuring the characteristics.

[0163] The average grain size of grains was measured according to planimetry of methods for estimating the average grain size of wrought copper and copper alloys defined in JIS H 0501 by selecting an appropriate magnification according to the size of grains based on metallographic microscopic images of, for example, magnifications of 300 times, 600 times, and 150 times. Twin was not considered as a grain. The average grain size was calculated according to planimetry (JIS H 0501).

[0164] One grain is elongated by rolling, but the volume of the grain is not substantially changed by rolling. In cross-sections obtained by cutting a sheet material in directions parallel to and perpendicular to a rolling direction, an average grain size in the stage of recrystallization can be estimated from the average grain size measured according to planimetry.

[0165] The ratio of an phase of each material was determined from images obtained by a metallurgical microscope at a magnification of 300 times (micrographs of a view field of 89 mm127 mm). When each material was etched using a mixed solution of ammonia water and hydrogen peroxide and the structure was observed by a metallurgical microscope, the phase was seen to be light yellow, the phase was seen to be a yellow deeper than the color of the phase, the phase was seen to be light blue, oxides and non-metallic inclusions were seen to be gray, and coarse metallic compounds were seen to be a light blue more bluish than the color of the phase or blue. Therefore, each phase of a, 0 and y, non-metallic inclusions and the like is easily distinguished from each other. The and phases in the observed metallographic structure were binarized using image processing software Win ROOF and the ratios of the areas of and phases with respect to the total ratio of the metallographic structure were obtained as area ratios. The metallographic structure was measured from three visual fields, and the average value of the respective area ratios was calculated. Regarding a seam welded pipe, the measurement was carried out in three visual fields each at a joint portion, a heat affected zone included in a heat affected zone 1 mm apart from the boundary between the joint portion and the heat affected zone, and an arbitrary portion of a base material and a total of the average values thereof was divided by 3.

[0166] The average particle size of precipitates was obtained as follows. Transmission electronic microscopic images were obtained using a TEM at a magnification of 500,000 times and a magnification of 150,000 times (detection limits were 2.0 nm), and the contrast of a precipitate was elliptically approximated using image analysis software Win ROOF. The geometric average value of long and short axes was obtained from each of all the precipitate particles in the field of view. The average value thereof was obtained as an average particle size. Precipitates having an average size of about less than 5 nm were measured at 750,000 times (the detection limit was 0.5 nm), and precipitates having an average size of about greater than 50 nm were measured at 50,000 times (the detection limit was 6 nm). In the case of a transmission electron microscope, since the cold-rolled material has a high dislocation density, it is difficult to accurately obtain precipitate information. In addition, the size of a precipitate is not changed by cold-rolling. Therefore, in this observation, recrystallized portions before the finish cold rolling process and after the recrystallization heat treatment process were observed. Two measurement positions were located at a depth of of the thickness of the sheet from both the front and rear surfaces of a rolled material and the measured values of the two positions were averaged.

[0167] Conductivity was measured using a conductivity measuring device (SIGMATEST D2.068, manufactured by Foerster Japan Ltd.). In this specification, electric conduction has the same definition as that of conduction. In addition, thermal conduction has a strong relationship with electric conduction. Therefore, the higher the electric conductivity is, the higher the thermal conductivity is.

[0168] A stress relaxation rate was measured as follows. In a stress relaxation test of a test material, a cantilever screw jig was used. Two test pieces were collected from a direction parallel with a rolling direction and a direction perpendicular to the rolling direction and had a shape of thickness 0.3 mmwidth 10 mmlength 60 mm. A load stress on the test material was set to be 80% with respect to a 0.2% proof stress test material that was exposed to an atmosphere of 150 C. and 120 C. for 1,000 hours. The stress relaxation rate was obtained from the following expression.

Stress relaxation rate=(displacement after relief/Displacement under load stress)100(%)

[0169] The average value of test pieces which were collected from both directions parallel with and perpendicular to the rolling direction was used. In the present invention, it is desired to obtain particularly excellent stress relaxation characteristics even in a CuZn alloy containing a high concentration of Zn. Therefore, when the stress relaxation rate at 150 C. is 25% or less, stress relaxation characteristics are excellent. When the stress relaxation rate is more than 25% and 35% or less, stress relaxation characteristics are satisfactory and when the rate is more than 35% and 50% or less, there is a problem in use. When the rate is more than 50%, there are difficulties in use. Particularly, when the rate is more than 70%, there is a significant problem in use in a high temperature environment and the sample is not available.

[0170] On the other hand, in a test under slightly mild conditions of 120 C. and 1,000 hours, higher performance is required. In a case in which the stress relaxation rate was 10% or less, the level of stress relaxation characteristics was high and this case was evaluated as

[0171] In a case in which the stress relaxation rate was more than 10% and 15% or less, stress relaxation characteristics were satisfactory and this case was evaluated as B. In a case in which the stress relaxation rate was more than 15% and 30% or less, there was a problem in use. In a case in which the stress relaxation rate was more than 30%, the test piece was substantially mild and there was little superiority as a material. In the specification, it is desired to obtain particularly excellent stress relaxation and thus the test piece having a stress relaxation rate of more than 15% was evaluated as C.

[0172] On the other hand, the maximum effective contact pressure is expressed by proof stress80%(100%stress relaxation rate (%)). In the alloy of the present invention, it is important that not only proof stress at room temperature be high or the stress relaxation rate be low, but also the value of the above expression be high. An alloy in which the value of proof stress80%(100%stress relaxation rate (%)) is 275 N/mm.sup.2 or more in the test at 150 C. can be used in a high temperature state and an alloy in which the value is 300 N/mm.sup.2 or more is suitably used in a high temperature state. An alloy in which the value is 325 N/mm.sup.2 or more is most suitable. In applications of yellow brass containing a large amount of Zn such as terminals and connectors, in the specification, it is desired to obtain color fastness which endures a severe high temperature and excellent stress relaxation characteristics and thus a high stress relaxation rate at 120 C. and 150 C. for 1,000 hours, or high effective stress is desired. In the specification, as proof stress and a stress relaxation rate, the average values of proof stress and stress relaxation rates of test pieces collected from two directions parallel with and perpendicular to the rolling direction are used. The proof stress and stress relaxation characteristics may not be obtained from a direction which forms 90 degrees (perpendicular) with respect to the rolling direction due to the relation with the width of a slit after being slit, that is, when the width is smaller than 60 mm. In this case, only from a direction which forms 0 degree (parallel) with respect to the rolling direction, the stress relaxation characteristics and the maximum effective contact pressure (effective stress) of a test piece are evaluated.

[0173] In test Nos. 31, 34 and 36 (Alloy No.3) and test Nos. 50, 54 and 54A (Alloy No. 4), it was confirmed that there was no significant difference among the effective stress calculated from the results of the stress relaxation test in a direction which forms 90 degrees (perpendicular) with respect to the rolling direction and a direction which forms 0 degree (parallel) with respect to the rolling direction, the effective stress calculated from the results of the stress relaxation test only in a direction which forms 0 degree (parallel) with respect to the rolling direction, and the effective stress calculated from the results of the stress relaxation test only in a direction which forms 90 degrees (perpendicular) with respect to the rolling direction.

[0174] Stress corrosion cracking properties were measured by adding sodium hydroxide and pure water to a test solution, that is, ammonium chloride by using a test container defined in ASTM B858-01 (107 g/500 ml) to adjust the pH to 10.10.1, and the air conditioning in a room was controlled to 23 C.1 C.

[0175] First, bending plastic working and residual stress were applied to a rolled material and stress corrosion cracking properties were evaluated. Using a bending workability evaluation method, which will be described later, a test piece which was subjected to W bending at R (radius: 0.6 mm) of two times the thickness of a sheet was exposed to the stress corrosion cracking environment. After a predetermined period of exposure time, the test piece was taken out and washed with sulfuric acid. Then, whether cracking occurred or not was investigated using a stereoscopic microscope at a magnification of 10 times (visual field of 200 mm200 mm, substantially, 20 mm20 mm (actual size)) to evaluate stress corrosion cracking resistance. Samples collected from a direction parallel with a rolling direction were used. A test piece in which cracking had not occurred through exposure for 48 hours had excellent stress corrosion cracking resistance and was evaluated as A. A test piece in which little cracking had occurred through exposure for 48 hours but cracking had not occurred through exposure for 24 hours had satisfactory stress corrosion cracking resistance (without any problem in practical use) and was evaluated as B. A test piece in which cracking occurred through exposure for hours had deteriorated stress corrosion cracking resistance (with a problem in practical use) and was evaluated as C.

[0176] Regarding a seam welded pipe, a sample which was crushed until a distance between flat sheets in a flattening test, which will be described later, became 5 times the thickness of the pipe was used.

[0177] In addition, stress corrosion cracking properties were evaluated by another method separately from the above-described evaluation.

[0178] In the stress corrosion cracking test, in order to investigate sensitivity for stress corrosion cracking in a state in which stress was applied, a resin cantilever screw type jig was used. A rolled material was exposed to the stress corrosion cracking atmosphere in a state in which as in the stress relaxation test, bending stress which was 80% of proof stress, that is, stress of the elastic limit of the material was applied, and stress corrosion cracking resistance was evaluated from the stress relaxation rate. That is, when minute cracking occurs, and a degree of the cracking increases without returning to the original state, the stress relaxation rate increases, and thus the stress corrosion cracking resistance can be evaluated. A test piece in which the stress relaxation rate through exposure for 24 hours was 15% or less had excellent stress corrosion cracking resistance and was evaluated as A. A test piece in which the stress relaxation rate was more than 15% and 30% or less had satisfactory stress corrosion cracking resistance and was evaluated as B. The use of a test piece in which the stress relaxation rate was more than 30% under a severe stress corrosion cracking environment was difficult and the sample was evaluated as C. The samples used were collected from a direction parallel with a rolling direction were used.

[0179] The tensile strength, proof stress, and elongation of the sheet material were measured according to methods defined in JIS Z 2201 and JIS Z 2241 and a No. 5 test piece was used regarding the shape of a test piece. Test pieces were collected from two directions parallel with and perpendicular to the rolling direction. Here, the width of the materials tested in the processes B and C was 120 mm and a test piece according to the No. 5 test piece was used.

[0180] The bending workability of a sheet material was evaluated in a W bending test defined in JIS H 3110. The bending (W-bending) test was carried out as follows. A bending radius was set to be one time (bending radius=0.3 mm, 1 t) and 0.5 times (bending radius=0.15 mm, 0.5 t) the thickness of a material. Samples were bent in a direction, in a so-called bad way, which forms 90 degrees with a rolling direction and in a direction, in a so-called good way, which forms 0 degrees with the rolling direction. In the evaluation of bending workability, whether cracking occurred or not was determined by observation using a stereoscopic microscope at a magnification of 20 times (view field of 200 mm200 mm, substantially, 10 mm10 mm (actual size)). A test piece in which cracking had not occurred when the bending radius was 0.5 times the thickness of a material was evaluated as A. A test piece in which cracking had not occurred when the bending radius was 1 time the thickness of a material was evaluated as B. A test piece in which cracking had occurred when the bending radius was 1 time the thickness of a material was evaluated as C.

[0181] For the mechanical properties of a seam welded pipe, a tensile test was carried out by using a No. 11 test piece of a metal material tensile test piece of JIS Z 2241 (gauge length: 50 mm, the test piece was used in a state in which the test piece was cut from the pipe material) and inserting a core bar into a grip portion.

[0182] First, the joint portion of the seam welded pipe was evaluated by carrying out a flattening test described in JIS H 3320 on a copper or copper alloy welded pipe. A sample was collected from a portion about 100 mm apart from the end of the seam welded pipe, the sample was interposed between two flat sheets and was crushed until a distance between the flat sheets became three times the thickness of the pipe. At this time, the joint portion of the seam welded pipe was arranged in a direction perpendicular to the compression direction and was subjected to flattening bending so that the joint portion became a tip end of bending. The state of the joint portion which was subjected to bending was visually observed. Next, a flaring test was carried out by a method described in JIS H 3320. In the flaring test, a conical tool with a vertical angle of 60 was pushed into one end of a sample of 50 mm cut from the welded pipe until a diameter of 1.25 times the outer diameter (that is, a diameter of 31.8 mm which was 1.25 times the diameter of the end portion of 25.4 mm by the flaring) was obtained and cracking of the welded portion was visually confirmed. Regarding the evaluation of both tests, a test piece in which defects such as cracking and minute holes were not observed was evaluated as A and a test piece which was not available due to defects such as cracking and holes occurred in the joint portion was evaluated as C.

[0183] In the color fastness to evaluate the color fastness of a material, using a thermo-hygrostat (HIFLEX FX2050, produced by Kusumoto Chemicals, Ltd.), each sample was exposed to an atmosphere at a temperature of 60 C. and a relative humidity of 95%. As a test piece, a test piece before a final recovery heat treatment is carried out, that is, a sheet material after finish rolling was used. The test time was set to 72 hours. The sample was taken out after the test, L*a*b* values of the surface color of the material before and after the exposure were measured by a spectrophotometer, and the color difference was calculated and evaluated. In copper and a copper alloy, particularly, a CuZn alloy containing a high concentration of Zn, the color changes to reddish brown or red. Due to this, for the evaluation of color fastness, a sample in which a difference between a* values before and after the test, that is, a value of a change in an a* value was 1 or less, was evaluated as A. A sample in which the difference was greater than 1 and 2 or less was evaluated as B. A sample in which the difference was greater than 2 was evaluated as It could be determined that as the numerical value increases, the color fastness deteriorates, and visual evaluation was also matched with the results.

[0184] On the assumption of a room, particularly, a cabin of an automobile and an engine room under the severe blazing sun, color fastness at a high temperature was evaluated. As a test piece, a sheet material before a final recovery heat treatment was carried out was used. In the atmosphere, the test piece was held in an electric furnace at 120 C. for 100 hours and L*a*b* values of the surface color before and after the test were measured by a spectrophotometer. As in the above test, for the evaluation of color fastness, a sample in which a difference between a* values before and after the test, that is, a value of a change in an a* value was 3 or less was evaluated as A. A sample in which the difference was greater than 3 and 5 or less was evaluated as B. A sample in which the difference was greater than 5 was evaluated as C.

[0185] The surface color (color tone) of the copper alloy to be evaluated in the color fastness test was expressed using a method of measuring an object color according to JIS Z 8722-2009 (Methods of color measurement-Reflecting and transmitting objects) and the L*a*b* color system defined in JIS Z 8729-2004 (Color specification-L*a*b* color system and L*u*v* color system). Specifically, a spectrophotometer CM-700d, produced by Konica Minolta, Inc. was used and the L*a*b* values before and after the test were measured at 3 points by a SCI (including specular reflection light) method.

[0186] The antimicrobial properties (bactericidal properties) were evaluated by a test method referring to JIS Z 2801 (Antimicrobial products-Test for antimicrobial activity and efficacy) and a film contact method, and the test area (film area) and the contact time were changed to conduct evaluation. Escherichia coli (stock No. of strain: NBRC3972) was used as the bacteria for the test. A solution, which was obtained by precultivating (as the preculture method, a method described in 5.6.a of JIS Z 2801 was used) Escherichia coli at 35 C.1 C. and diluting Escherichia coli with 1/500 NB to adjust the number of bacteria to 1.010.sup.6 cells/mL, was used as a test bacterial suspension. In the test method, samples were obtained by cutting from the sheet material after finish rolling, the sample after the high temperature high humidity test at 60 C. and a humidity of 95%, and the sample after the high temperature test at 120 C. for 100 hours into 20 mm20 mm. Each sample was put into a sterilized petri dish, 0.045 mL of the above-described test bacterial suspension (Escherichia coli: 1.010.sup.6 cells/mL) was added dropwise thereto, and the petri dish was covered with a (215 mm film and then covered with a lid. The test bacterial suspension was cultivated for 10 minutes (inoculation time: 10 minutes) in the petri dish in an atmosphere of 35 C.1 C. and a relative humidity of 95%. This cultivated test bacterial suspension was washed away with 10 mL of SCDLP culture medium to obtain a wash-away bacterial suspension. The wash-away bacterial suspension was diluted 10 times with a phosphate buffered saline solution. Standard plate count agar was added to this bacterial suspension, followed by cultivation at 35 C.1 C. for 48 hours. When the number of colonies was more than or equal to 30, the number of colonies was measured to obtain the viable bacterial count (cfu/mL). The number of colonies at the time of inoculation (the bacterial count when the test for antimicrobial properties started; cfu/mL) was set as a criterion.

[0187] First, the viable bacterial count of each sample after the finish rolling was carried out was compared to the viable bacterial count. A case in which the rate was less than 10% was evaluated as A. A case in which the rate was 10% to less than 33% was evaluated as B. A case in which the rate was 33% or more was evaluated as C. For samples which were evaluated as A (that is, the viable bacterial count of the evaluation sample was less than 1/10 of the viable bacterial count at the time of inoculation), antimicrobial properties (bactericidal properties) were evaluated to be excellent, and for samples which were evaluated as B (that is, the viable bacterial count of the evaluation sample was less than of the viable bacterial count at the time of inoculation), antimicrobial properties (bactericidal properties) were evaluated to be satisfactory. The reason why the culture time (inoculation time) at 10 minutes was short is that the immediate activity for antimicrobial properties (bactericidal properties) was evaluated.

[0188] Next, in the evaluation of antimicrobial properties (bactericidal properties), a case in which the relationship between a viable bacterial rate C.sub.H obtained from the samples after the two color fastness tests and a case in which a viable bacterial rate C.sub.0 before the color fastness tests was C.sub.H1.10C.sub.0 was evaluated as A, a case in which the relationship was 1.10C.sub.0<C.sub.H1.25C.sub.0 was evaluated as B, and a case in which the relationship was C.sub.H>1.25C.sub.0 was evaluated as C. That is, when the color of the copper alloy is changed, there is a concern of lowering of antimicrobial performance. In the alloy of the present invention, a slight color change by the severe test at a high temperature and high humidity or at a high temperature is observed and the formation of oxides and the like on the outermost surface layer of the surface is predicted. In these samples whose color is slightly changed, compared to a sample having a clean surface before the tests, the antimicrobial performance of a sample evaluated as A or at least B is not impaired.

[0189] In addition, separately from the above evaluation, antimicrobial properties were evaluated in the following method. As a test piece (container), a material for a seam welded pipe having a thickness of 1 mm was used and the sheet material was punched by a punch to have a hole of 125 mm. The punched sheet material was formed into a cup shape having a bottom surface of 80 mm and a height of 50 mm by metal spinning, and washed and degreased with acetone for about 5 minutes by ultrasonic washing. A total three samples of one test piece which was used after the test piece was formed and two other test pieces of a sample obtained by subjecting a high temperature high humidity test having conditions of a temperature of 60 C. and humidity of 95% to the cup-shaped test piece and a sample obtained by subjecting a high temperature test having conditions of a temperature of 120 C. for 100 hours to the cup-shaped test piece were prepared. Regarding Alloy No. 201 as a comparative material, a material which had been sampled at a stage of 1 mm and has been subjected to a heat treatment at 430 C. for 4 hours was used.

[0190] In the antimicrobial property test, Escherichia coli (NBRC3972) were shake-cultured in 5 mL of a normal broth culture medium for one night at 27 C. and then 1 mL of the culture medium was centrifugally separated to obtain bacterial cells. The bacterial cells were suspended in 1 mL of sterilized saline solution (0.85%) and the suspension was diluted 1,200 times with sterilized water including the normal broth culture medium to a final concentration of 1/500. 200 mL of a suspension of a viable bacterial count of Escherichia coli of about 810.sup.6 cfu/mL was poured into each of the above three kinds of test containers and left at air-conditioned room temperature (about 25 C.). After 4 hours, 0.05 mL of the suspension was collected to 4.95 mL of SCDLP culture medium DAIGO and diluted 10 times with 4 stages. Then, the viable bacterial count in 1 mL of each suspension was measured. When the viable bacterial count before the test was compared to the viable bacterial count after 4 hours, a case in which the rate was less than 3% was evaluated as A. A case in which the rate was 3% to less than 10% was evaluated as B. A case in which the rate was 10% or more was evaluated as C. For samples which were evaluated as A (that is, the viable bacterial count of the evaluation sample was less than 1/33 of the viable bacterial count at the time of inoculation), antimicrobial properties (bactericidal properties) were evaluated to be excellent, and for samples which were evaluated as B (that is, the viable bacterial count of the evaluation sample was less than 1/10 of the viable bacterial count at the time of inoculation), antimicrobial properties (bactericidal properties) were evaluated to be satisfactory. The evaluation of maintaining antimicrobial properties (bactericidal properties) based on color change was carried out using the viable bacterial rate C.sub.H.

[0191] That is, when the initial sample of the finish rolled material was evaluated as A and the sample after the severe test was also evaluated as A or at least B, sufficient antimicrobial performance and bactericidal performance were provided in actual used apparatuses and metal fittings. A material suitable for applications such as public-based use such as public facilities, hospitals, welfare facilities, and vehicles, handrails, door handles, door knobs, and door levers, which many people use in a building or the like, medical appliances, medical containers, headboards, footboards, and water supply and drain sanitary facilities and apparatuses such as a drainage tank used in vehicles and the like can be obtained.

[0192] The evaluation results of the sheet materials are shown in Tables 6 to 25. The evaluation results of the seam welded pipes are shown in Table 26. The evaluation results of antimicrobial properties are shown in Tables 27 and 28.

TABLE-US-00006 TABLE 6 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 1 A1-1 1 100 4 17 25 A 340 A B 2 A1-2 100 4 17 26 B 333 A B 3 A1-3 100 4 17 28 B 327 A B 4 A1-4 100 7 17 23 A 334 A B 5 A2-1 100 5 17 25 B 335 A B 6 A2-2 100 5 17 23 A 341 A B 7 A2-3 100 5 17 25 B 336 A B 8 A2-4 100 5 16 A B 9 A2-5 100 6 17 23 A 365 A B 9A A2-6 100 6 17 28 B 344 A B 9B A2-7 100 9 16 24 A 341 A B 9C A2-8 100 30 16 27 B 295 B B 9D A2-10 100 1.5 17 27 B 367 A B 11 B1-1 100 5 17 25 B 335 A B 12 B1-2 100 5 17 27 B 329 A B 13 B1-3 100 5 17 23 A 344 A B 14 B2-1 100 5 17 25 B 343 A B 15 B3-1 100 6 17 26 B 321 A B 15A B3-2 100 6 17 26 B 322 A B

TABLE-US-00007 TABLE 7 Color fastness Direction parallel with Direction orthogonal to High rolling direction rolling direction temperature Tensile Proof Tensile Proof high High strength stress Elon- strength stress Elon- Bending workability humidity temperature Test Production Alloy TS.sub.p YS.sub.p gation TS.sub.o YS.sub.o gation Good Way Bad Way test test No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) (Evaluation) 1 A1-1 1 609 562 15 623 572 12 A A A A 2 A1-2 612 566 14 618 560 11 A A 3 A1-3 618 573 13 622 562 10 A A 4 A1-4 579 539 22 590 546 16 A A 5 A2-1 594 555 18 616 562 11 A A A A 6 A2-2 584 548 18 615 560 12 A A 7 A2-3 596 555 16 622 564 11 A A 8 A2-4 590 549 18 609 526 12 A A A A 9 A2-5 633 586 11 659 598 9 A B 9A A2-6 645 598 10 672 595 7 A B 9B A2-7 600 552 12 622 570 11 A B A A 9C A2-8 538 476 13 576 533 12 A B 9D A2-10 652 601 9 706 656 6 B C 10 A3-1 488 392 42 A A 11 B1-1 595 551 17 615 565 12 A A A A 12 B1-2 604 565 16 618 560 11 A A 13 B1-3 589 550 18 615 567 12 A A 14 B2-1 603 562 16 628 580 11 A A A A 15 B3-1 584 538 20 604 547 13 A A A A 15A B3-2 580 539 19 602 550 13 A A A A

TABLE-US-00008 TABLE 8 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 16 A1-1 2 100 3 15 21 A 366 A A 17 A1-2 100 3 15 22 A 362 A A 18 A1-3 100 3 15 25 B 349 A A 19 A1-4 100 6 15 20 A 352 A A 20 A2-1 100 4 15 21 A 361 A A 21 A2-2 100 4 15 20 A 364 A A 22 A2-3 100 4 15 23 A 354 A A 23 A2-4 100 4 15 A A 24 A2-5 100 6 15 20 A 388 A A 26 B1-1 100 4 15 21 A 361 A A 27 B1-2 100 4 15 23 A 356 A A 28 B1-3 100 4 15 20 A 360 A A 29 B2-1 100 3 15 21 A 366 A A 30 B3-1 100 5 15 22 A 347 A A 30A B3-2 100 5 15 21 A 351 A A

TABLE-US-00009 TABLE 9 Color fastness Direction parallel with Direction orthogonal to High rolling direction rolling direction temperature Tensile Proof Tensile Proof high High strength stress Elon- strength stress Elon- Bending workability humidity temperature Test Production Alloy TS.sub.p YS.sub.p gation TS.sub.o YS.sub.o gation Good Way Bad Way test test No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) (Evaluation) 16 A1-1 2 622 577 15 636 582 11 A A A A 17 A1-2 625 581 13 632 579 10 A A 18 A1-3 632 585 12 638 578 10 A A 19 A1-4 591 550 20 603 550 15 A A 20 A2-1 607 564 17 630 578 11 A A A A 21 A2-2 609 561 17 626 575 11 A A 22 A2-3 615 574 16 632 574 10 A A 23 A2-4 605 563 16 622 541 11 A A A A 24 A2-5 642 602 11 668 612 8 A B 25 A3-1 531 445 36 A A 26 B1-1 604 565 17 626 576 11 A A A A 27 B1-2 617 574 15 626 581 10 A A 28 B1-3 592 554 17 624 572 12 A A 29 B2-1 616 573 15 641 585 10 A A A A 30 B3-1 598 552 18 617 559 12 A A A A 30A B3-2 592 551 18 612 560 12 A A A A

TABLE-US-00010 TABLE 10 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 31 A1-1 3 100 3 40 16 16 A 395 A B 32 A1-2 100 3 40 16 16 A 397 A B 33 A1-3 100 3 40 15 18 A 395 A B 34 A1-4 100 6 50 16 12 A 394 A B 35 A2-1 100 4 40 16 16 A 392 A B 36 A2-2 100 4 35 16 13 A 404 A B 37 A2-3 100 4 35 15 15 A 396 A B 38 A2-4 100 4 40 15 A B 39 A2-5 100 6 60 16 13 A 429 A B 41 B1-1 100 4 40 16 16 A 392 A B 42 B1-2 100 4 30 15 15 A 399 A B 43 B1-3 100 4 30 16 12 A 408 A B 44 B2-1 100 3 35 16 18 A 388 A B 45 B3-1 100 5 60 16 18 A 373 A B 45A B3-2 100 5 55 16 13 A 396 A B

TABLE-US-00011 TABLE 11 Color fastness Direction parallel with Direction orthogonal to High rolling direction rolling direction temperature Tensile Proof Tensile Proof high High strength stress Elon- strength stress Elon- Bending workability humidity temperature Test Production Alloy TS.sub.p YS.sub.p gation TS.sub.o YS.sub.o gation Good Way Bad Way test test No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) (Evaluation) 31 A1-1 3 635 586 13 643 590 10 A B A A 32 A1-2 633 589 13 646 592 10 A B 33 A1-3 640 597 12 662 606 9 A B 34 A1-4 603 556 20 615 562 16 A A 35 A2-1 624 580 16 638 586 11 A B A A 36 A2-2 617 577 17 635 583 12 A A 37 A2-3 621 579 15 640 586 9 A B 38 A2-4 616 580 16 634 552 11 A B A A 39 A2-5 651 611 11 686 622 9 A B 41 B1-1 617 578 16 637 588 11 A B A A 42 B1-2 627 581 15 648 593 10 A B 43 B1-3 613 575 16 638 585 12 A A 44 B2-1 628 587 14 655 597 10 A B A A 45 B3-1 613 566 18 630 570 12 A A A A 45A B3-2 609 563 18 625 574 12 A A A A

TABLE-US-00012 TABLE 12 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 46 A1-1 4 100 3 40 19 19 A 367 A A 47 A1-2 100 3 40 19 19 A 367 A A 48 A1-3 100 3 40 19 22 A 358 A A 49 A1-4 100 6 50 19 15 A 364 A A 50 A2-1 100 4 40 19 19 A 362 A A 51 A2-2 100 4 30 19 16 A 375 A A 52 A2-3 100 4 30 19 18 A 371 A A 53 A2-4 100 4 30 18 A A 54 A2-5 100 6 50 19 14 A 408 A A .sup.54A A2-6 100 6 50 18 19 A 392 A A .sup.54B A2-7 100 8 70 18 16 A 378 A A .sup.55C A2-8 100 30 200 18 26 B 297 A A .sup.55D A2-9 100 12 220 20 28 B 306 A B .sup.56E A2-10 100 1.5 6 19 20 A 404 A A 56 B1-1 100 4 40 19 19 A 364 A A 57 B1-2 100 4 30 18 19 A 366 A A 58 B1-3 100 4 30 18 15 A 378 A A 59 B2-1 100 3 30 19 20 A 366 A A 60 B3-1 100 5 60 19 20 A 348 A A .sup.60A B3-2 100 5 19 16 A 370 A A

TABLE-US-00013 TABLE 13 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 46 A1-1 4 608 564 15 620 570 11 A A A A 47 A1-2 611 566 14 621 568 10 A A 48 A1-3 620 573 13 634 576 9 A A 49 A1-4 577 536 20 588 536 16 A A 50 A2-1 594 552 17 613 565 11 A A A A 51 A2-2 592 555 18 610 561 12 A A 52 A2-3 603 568 17 622 563 10 A A 53 A2-4 590 548 17 609 528 11 A A A A 54 A2-5 630 586 11 662 601 9 A A .sup.54A A2-6 643 598 9 675 611 7 A B .sup.54B A2-7 595 552 12 618 572 10 A A A A 55 A3-1 470 372 41 A A .sup.55C A2-8 533 472 13 574 530 11 A B .sup.55D A2-9 563 500 12 622 562 8 A B .sup.56E A2-10 658 601 9 717 660 6 B C 56 B1-1 594 558 18 616 564 11 A A A A 57 B1-2 601 562 17 620 569 10 A A 58 B1-3 587 548 18 612 563 12 A A 59 B2-1 604 566 15 633 577 10 A A A A 60 B3-1 585 538 19 607 550 13 A A A A .sup.60A B3-2 590 543 18 608 558 12 A A

TABLE-US-00014 TABLE 14 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 61 A2-1 5 100 4 50 21 20 A 351 A A 62 A2-2 100 4 21 15 A 370 A A 63 A2-3 100 4 21 19 A 362 A A 64 A2-4 100 4 20 A A 65 A2-5 100 6 21 14 A 402 A A 67 B1-1 100 4 50 21 20 A 351 A A 68 B1-2 100 4 21 19 A 360 A A 69 B1-3 100 4 21 14 A 375 A A 70 B2-1 100 4 40 21 22 A 348 A A 71 B3-1 100 5 60 21 20 A 342 A A .sup.71A B3-2 100 5 21 16 A 360 A A 72 A2-1 6 100 3 35 18 17 A 379 A A .sup.72A A2-2 100 3 14 A 392 A A 74 B1-1 7 100 4 35 18 15 A 377 A B 75 A2-1 100 4 16 21 A 358 A A 77 B1-1 100 4 17 23 A 345 A A 78 A2-1 8 100 3 35 18 28 B 333 A B .sup.78A A2-2 99.9 4 30 B 321 B B 80 B1-1 100 4 40 18 27 B 327 A B

TABLE-US-00015 TABLE 15 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 61 A2-1 5 580 546 17 601 550 11 A A A B 62 A2-2 579 540 18 596 548 12 A A 63 A2-3 592 561 16 606 556 10 A A 64 A2-4 580 540 17 595 518 11 A A A B 65 A2-5 618 576 12 654 593 9 A A 67 B1-1 580 542 18 603 555 11 A A A B 68 B1-2 590 547 17 613 565 9 A A 69 B1-3 576 538 18 599 553 12 A A 70 B2-1 590 552 16 614 563 10 A A A B 71 B3-1 572 531 19 593 538 12 A A A B .sup.71A B3-2 570 530 19 588 540 12 A A 72 A2-1 6 610 568 16 626 574 11 A A A A .sup.72A A2-2 606 563 16 622 576 11 A A A A 74 B1-1 595 552 19 611 558 13 A A A A 75 A2-1 7 604 564 15 622 569 12 A A A A 77 B1-1 592 553 18 615 566 13 A A A A 78 A2-1 8 618 576 15 640 580 10 A B A A .sup.78A A2-2 614 572 15 635 576 9 A B 80 B1-1 599 556 16 623 563 10 A B A A

TABLE-US-00016 TABLE 16 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 101 C1 11 100 5 17 30 B 319 B B 102 C1 12 100 4 19 26 B 340 B B 103 C1 13 100 4 18 27 B 339 A B 104 C1 14 100 4 30 18 20 A 364 B B 105 C1 15 100 5 17 28 B 321 B B 106 C1 16 100 3 25 20 21 A 355 A B .sup.106A C1A 16 100 3 30 19 17 A 372 A B 107 C1 17 100 4 15 22 A 353 A B 108 C1 18 100 4 20 22 A 342 A A 109 C1 19 100 4 17 23 A 345 A A 110 C1 20 100 4 22 29 B 309 A B 111 C1 21 100 4 14 19 A 362 A A 112 C1 22 100 3 18 15 A 379 A A 113 C1 23 100 5 19 24 A 328 A A 114 C1 24 100 5 22 28 B 308 A A 115 C1 25 100 4 14 23 A 349 A A 116 C1 26 100 5 18 22 A 341 A A 117 C1 27 100 4 18 17 A 366 A A .sup.117A C1A 27 100 4 17 13 A 385 A A

TABLE-US-00017 TABLE 17 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 101 C1 11 602 563 16 636 578 10 A B A A 102 C1 12 612 569 16 643 580 10 A B B B 103 C1 13 623 577 15 643 583 10 A B A B 104 C1 14 607 565 16 631 574 11 A A A A 105 C1 15 598 550 17 621 563 12 A A A A 106 C1 16 604 558 16 624 565 10 A A B B .sup.106A C1A 16 600 555 17 622 565 11 A A A B 107 C1 17 605 560 17 629 571 11 A A A A 108 C1 18 588 543 17 610 554 12 A A A B 109 C1 19 600 557 17 623 564 11 A A A A 110 C1 20 582 550 18 592 537 12 A A B B 111 C1 21 600 554 17 618 563 11 A A A A 112 C1 22 600 552 16 620 564 11 A B A A 113 C1 23 583 534 18 600 545 12 A A A A 114 C1 24 568 526 18 586 544 12 A A B B 115 C1 25 605 563 16 626 571 10 A A A A 116 C1 26 580 541 17 604 551 12 A A A B 117 C1 27 589 540 18 621 563 12 A A A A .sup.117A C1A 27 590 542 19 624 565 12 A A A A

TABLE-US-00018 TABLE 18 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective W Stress Test Production Alloy phase size particle size Conductivity hours hours stress Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 118 C1 28 100 3 20 19 19 A 369 A B 119 C1 29 100 2.5 10 18 21 A 366 A B 120 C1 30 100 3 15 18 19 A 369 A A 121 C1 31 100 3 17 25 A 340 A B 122 C1 32 100 4 16 24 A 341 A B 123 C1 33 100 3 16 17 A 388 B B 124 C1 34 100 4 18 19 A 363 A B 125 C1 35 100 3 17 25 A 341 A B 126 C1 36 100 3 19 19 A 369 A B 127 C1 37 100 4 16 24 A 340 A B 128 C1 38 100 4 16 17 A 384 A A 129 C1 39 100 4 17 25 B 338 A A 130 C1 40 100 4 18 19 A 360 B B 131 C1 41 100 4 15 21 A 362 A A 132 C1 42 100 4 16 24 A 342 A A 133 C1 43 100 5 21 26 B 307 A B 134 C1 44 100 3 18 27 B 334 A B 135 C1 45 100 4 17 20 A 364 A A

TABLE-US-00019 TABLE 19 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 118 C1 28 604 567 17 626 573 10 A A A B 119 C1 29 619 568 16 640 591 10 A B A A 120 C1 30 609 568 16 631 572 10 A A A A 121 C1 31 603 558 16 632 575 10 A A A A 122 C1 32 595 556 17 620 565 11 A A A A 123 C1 33 623 583 15 645 587 10 A B A A 124 C1 34 598 553 18 617 566 12 A A A A 125 C1 35 608 563 16 632 574 11 A A A A 126 C1 36 606 568 16 630 570 11 A A A B 127 C1 37 593 553 18 621 565 12 A A A A 128 C1 38 614 574 16 634 582 11 A B A A 129 C1 39 602 558 17 624 570 11 A A A A 130 C1 40 597 551 19 618 561 11 A A A A 131 C1 41 608 569 17 632 575 11 A A A A 132 C1 42 600 558 17 626 567 12 A A A A 133 C1 43 553 513 17 571 524 13 A A B B 134 C1 44 613 561 15 642 582 11 A B A B 135 C1 45 610 565 16 630 572 11 A A A A

TABLE-US-00020 TABLE 20 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 201 A2-1 101 99.6 4 17 42 C 267 C C 202 A2-2 99.5 4 17 43 C 261 C C 203 A2-3 99.5 4 17 48 C 242 C C 204 A2-4 99.5 4 16 C C 205 A2-5 99.1 4 17 42 C 286 C C 207 B1-1 99.6 4 17 42 C 268 C C 208 B1-2 99.5 4 17 45 C 259 C C 209 B1-3 99.5 4 17 44 C 257 C C 210 B2-1 99.5 3 17 43 C 269 C C 211 B3-1 99.8 5 17 39 C 274 B C 212 A2-1 102 99.7 3 50 19 41 C 273 C B .sup.212A A2-2 99.3 4 44 C 259 C C 214 B1-1 99.8 4 50 19 37 C 287 B C

TABLE-US-00021 TABLE 21 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 201 A2-1 101 610 568 15 650 582 8 A C A B 202 A2-2 616 569 15 645 577 8 A C 203 A2-3 623 577 12 655 585 6 B C 204 A2-4 610 566 14 638 550 7 B C B B 205 A2-5 650 581 8 705 653 3 B C 207 B1-1 621 567 14 659 589 8 A C B B 208 B1-2 618 578 14 665 597 7 B C 209 B1-3 608 566 15 643 582 8 A C 210 B2-1 624 579 13 665 600 6 A C B B 211 B3-1 601 554 16 632 569 10 A B B B 212 A2-1 102 620 568 14 663 590 7 A C B B .sup.212A A2-2 624 570 12 675 588 7 B C 214 B1-1 603 557 17 648 580 8 A B B B

TABLE-US-00022 TABLE 22 Stress relaxation Structure observation characteristics Stress corrosion Ratio Average Precipitate 150 C. 120 C. cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle size Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 301 C1 103 100 5 21 43 C 246 C C .sup.301A C1A 103 99.9 5 20 45 C 238 C C 302 C1 104 100 5 23 49 C 214 C C 303 C1 105 100 3 14 36 C 302 C C .sup.303A C1A 105 99.7 3 14 42 C 276 C C 304 C1 106 100 4 13 39 C 291 B C 305 C1 107 99.7 4 14 43 C 269 B B 306 C1 108 100 2 20 35 C 296 B C 307 C1 109 99.7 4 18 40 C 275 B C .sup.307A C1A 109 99 4 18 48 C 240 C C 308 C1 110 99.7 4 17 45 C 247 C C 309 C1 111 100 6 23 48 C 215 B C 310 C1 112 100 4 20 35 C 286 C C 311 C1 113 99.5 4 14 42 C 273 B C 312 C1 114 100 4 18 41 C 268 B B 313 C1 115 100 5 19 47 C 235 C C 314 C1 116 99.5 3 16 41 C 275 C C 315 C1 117 99.2 4 17 54 C 209 C C 316 C1 118 99.4 3 18 50 C 231 C C 317 C1 119 100 6 24 33 B 256 A A 318 C1 120 100 1.5 2 18 28 B 357 B B 319 C1 121 100 1.5 2 17 27 B 359 B B 320 C1 122 100 6 21 49 C 214 B C 321 C1 123 100 8 23 39 C 239 A A 322 C1 124 100 6 23 32 B 269 A A 323 C1 125 100 6 20 34 C 264 A A 324 C1 126 100 2.5 19 29 B 339 A B

TABLE-US-00023 TABLE 23 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 301 C1 103 577 536 17 596 545 11 A A C B .sup.301A C1A 103 582 538 16 608 544 8 A B C B 302 C1 104 560 515 18 588 532 11 A A C C 303 C1 105 628 578 13 672 603 7 A C B B .sup.303A C1A 105 635 582 13 680 607 6 B C B B 304 C1 106 635 583 12 680 610 6 B C B A 305 C1 107 631 580 12 677 601 6 B C B B 306 C1 108 604 556 14 644 581 8 A C B B 307 C1 109 608 560 13 656 584 7 A C C C .sup.307A C1A 109 616 561 10 667 592 6 B C C C 308 C1 110 600 551 14 642 572 8 A C C B 309 C1 111 554 510 18 577 525 13 A A C C 310 C1 112 589 540 17 628 559 9 A C B B 311 C1 113 632 580 12 670 598 7 B C C B 312 C1 114 603 560 13 647 577 7 A C A B 313 C1 115 591 544 15 630 566 7 A C B B 314 C1 116 620 573 13 662 592 6 A C C B 315 C1 117 608 559 14 651 578 7 A C C B 316 C1 118 614 568 13 660 585 6 A C C C 317 C1 119 515 473 19 540 483 14 A A C C 318 C1 120 651 601 13 718 640 5 B C A A 319 C1 121 643 597 14 706 632 6 A C A A 320 C1 122 550 516 18 584 532 12 A A C B 321 C2 123 525 483 18 547 496 13 A A B C 322 C3 124 534 488 16 555 501 12 A A B C 323 C4 125 537 495 17 560 504 13 A A B B 324 C5 126 638 582 12 679 610 8 A C A B

TABLE-US-00024 TABLE 24 Stress relaxation Structure observation characteristics Ratio Average Precipitate 150 C. 120 C. Stress corrosion cracking of grain average 1,000 1,000 Effective Stress Test Production Alloy phase size particle Conductivity hours hours stress W Bending relaxation No. process No. (%) (m) size (nm) (% IACS) (%) (%) (N/mm.sup.2) (Evaluation) (Evaluation) 401 C2 201 100 7 28 85 C 58 C C 402 C2 202 100 6 29 80 C 77 B C 403 C2 203 100 7 31 76 C 91 A B 404 C2 204 100 9 34 72 C 100 A A 405 205 100 12 12 59 C 189 A A

TABLE-US-00025 TABLE 25 Color fastness Direction parallel with Direction orthogonal to High High rolling direction rolling direction temperature temper- Tensile Proof Tensile Proof high ature Produc- strength stress strength stress Bending workability humidity test Test tion Alloy TS.sub.p YS.sub.p Elongation TS.sub.o YS.sub.o Elongation Good Way Bad Way test (Eval- No. process No. (N/mm.sup.2) (N/mm.sup.2) (%) (N/mm.sup.2) (N/mm.sup.2) (%) (Evaluation) (Evaluation) (Evaluation) uation) 401 C2 201 520 478 15 555 490 10 A B C C 402 C2 202 518 480 15 547 487 11 A B C C 403 C2 203 500 472 15 517 473 11 A A C C 404 C2 204 472 445 13 490 450 10 A A C C 405 205 635 564 24 665 591 16 A B C C

TABLE-US-00026 TABLE 26 Structure observation Structure Mechanical strength of the (board) observation (seam seam welded pipe, workability Stress Ratio Average welded pipe) Tensile Proof Flattening Pipe corrosion Produc- of grain strength stress test expansion cracking Test tion Alloy phase size phase phase phase Conductivity TS YS Elongation (Evalu- (Evalu- (Evalu- No. process No. (%) (m) (%) (%) (%) (% IACS) (N/mm.sup.2) (N/mm.sup.2) (%) ation) ation) ation) 10 A3-1 1 100 15 100 0 0 17 488 392 42 A A A 25 A3-1 2 100 12 100 0 0 15 531 445 36 A A A 40 A3-1 3 100 10 100 0 0 16 540 458 37 A A A 55 A3-1 4 100 18 100 0 0 19 470 372 41 A A A 66 A3-1 5 100 15 100 0 0 21 475 366 41 A A A 73 A3-1 6 100 12 100 0 0 18 512 423 40 A A 76 A3-1 7 100 10 100 0 0 16 526 440 38 A A A 79 A3-1 8 100 12 99.8 0.1 0.1 18 520 433 29 A A B 206 A3-1 101 99.6 10 98.9 0.7 0.4 17 540 455 30 C C C 213 A3-1 102 99.6 99.3 0.6 0.1 19 525 441 32 C C C

TABLE-US-00027 TABLE 27 Antimicrobial test After high After high Produc- After finish temperature high temperature Test tion Alloy rolling humidity test test No. process No. (Evaluation) (Evaluation) (Evaluation) 5 A2-1 1 A A A 20 A2-1 2 A A A 35 A2-1 3 A A A 50 A2-1 4 A A A 61 A2-1 5 A A A 72 A2-1 6 A A A 75 A2-1 7 A A A 78 A2-1 8 A A A 201 A2-1 101 B B 212 A2-1 102 B A 401 C2 201 A B B

TABLE-US-00028 TABLE 28 Antimicrobial test After high After high Produc- After finish temperature high temperature Test tion Alloy rolling humidity test test No. process No. (Evaluation) (Evaluation) (Evaluation) 10 A3-1 1 A A A 25 A3-1 2 A A A 40 A3-1 3 A A A 55 A3-1 4 A A A 73 A3-1 6 A A A 76 A3-1 7 A A A 206 A3-1 101 B B 402 C2 202 A B B

[0193] From the above evaluation results, regarding the compositions, the composition relational expression and the characteristics, the following was confirmed.

[0194] Due to the fact that all conditions of containing 17 mass % to 34 mass % of Zn, 0.02 mass % to 2.0 mass % of Sn, 1.5 mass % to 5 mass % of Ni, and a balance consisting of Cu and unavoidable impurities, satisfying relationships of 12f130, 10f228, 10f333, 1.2f44 and 1.4f590, and having a metallographic structure in which a ratio of an phase in the constituent phase of the metallographic structure is 99.5% or more by area ratio, and the like were satisfied, a CuZn alloy containing a high concentration of Zn and having excellent color fastness, high strength, good bending workability, satisfactory color fastness, stress relaxation characteristics and stress corrosion cracking resistance at a high temperature and high humidity or at a high temperature was obtained (refer to test Nos. 5, 20, 109, 113 and the like).

[0195] Additionally, when the alloy contains Sb, As, P and Al, color fastness and stress corrosion cracking resistance were further improved (refer to test Nos. 50, 72, 75, 122, 128 to 131 and the like).

[0196] Due to the fact that conditions of containing 18 mass % to 33 mass % of Zn, 0.2 mass % to 1.5 mass % of Sn, 1.5 mass % to 4 mass % of Ni, and a balance consisting of Cu and unavoidable impurities, satisfying relationships of 15f130, 12f228, 10f330, 1.4f43.6 and 1.6f512, and having a metallographic structure composed of an single phase were satisfied, excellent color fastness, high strength, good bending workability, and excellent stress relaxation characteristics were obtained. Therefore, a CuZn alloy containing a high concentration of Zn and having high effective stress in a use environment at a high temperature, and satisfactory stress corrosion cracking resistance in a state in which stress close to the elastic limit of the material was loaded and in a state in which high residual stress was present was obtained (refer to test Nos. 5, 20, 107 and the like).

[0197] Additionally, due to the fact that conditions of containing 0.003 mass % to 0.08 mass % of P and satisfying a relationship of 25[Ni]/[P]750 were satisfied, stress relaxation characteristics were further improved, stress corrosion cracking resistance and color fastness were also improved (refer to test Nos. 35, 50, 72 and the like).

[0198] When the amount of Zn was more than 34 mass %, bending workability was deteriorated and stress relaxation characteristics, stress corrosion cracking resistance and color fastness were deteriorated. When the amount of Zn was less than 17 mass %, strength was lowered and color fastness was also deteriorated (refer to test Nos. 303, 303A, 304, 317 and the like).

[0199] When the amount of Ni was less than 1.5 mass %, stress relaxation characteristics, stress corrosion cracking resistance and color fastness were deteriorated. When the amount of Ni was more than 1.5 mass %, stress relaxation characteristics, stress corrosion cracking resistance and color fastness were improved (refer to test Nos. 301, 301A, 302, 320, 102, 110 and the like).

[0200] When the amount of Sn was less than 0.02 mass %, strength was lowered and stress relaxation characteristics were deteriorated. When the amount of Sn was 0.2 mass % or more, strength was increased and color fastness and stress relaxation characteristics were improved. When the amount of Sn was more than 0.2 mass %, hot workability and bending workability were deteriorated, and stress relaxation characteristics and stress corrosion cracking resistance were deteriorated. When the amount of Sn was 1.5 mass % or less, hot workability and bending workability were impaired, and stress relaxation characteristics and stress corrosion cracking resistance were improved. In Test No. 305, since edge cracking occurred at the time of hot rolling, the cracked portion was removed and then the subsequent process was carried out (refer to test Nos. 110, 101, 104, 130, 305, 309, 321, 322 and the like).

[0201] In the composition relational expression f1=[Zn]+5[Sn]2[Ni], when the value was greater than 30, 0 and phases other than an phase appeared and bending workability, stress relaxation characteristics, stress corrosion cracking resistance, color fastness and antimicrobial properties (bactericidal properties) were deteriorated. In addition, it was found that the value of the composition relational expression f1=[Zn]+5[Sn]2[Ni] was a boundary value for determining whether bending workability, stress relaxation characteristics, stress corrosion cracking resistance and color fastness are good or not (refer to test Nos. 50, 56, 80, 101 to 105, 307, 307A, 308, 314 to 316 and the like).

[0202] In the sheet material, when the ratio of the phase was less than 99.5% or less than 99.8%, bending workability, stress relaxation characteristics, stress corrosion cracking resistance, color fastness and antimicrobial properties were deteriorated. However, when the ratio of the phase was 100%, these characteristics were improved and balance among tensile strength, proof stress and elongation was good. Further, when the ratio of the phase was 100%, in samples collected from directions parallel with and perpendicular to the rolling direction, the ratio of tensile strength in the collection directions, the ratio of proof stress, and the ratio between tensile strength and proof stress in the same collection direction were close to 1 (refer to test Nos. 50, 56, 80, 101 to 105, 307, 307A, 308, 311, 314 to 316, and the like).

[0203] In the seam welded pipe, when the ratio of the a phase in the constituent phase of the metallographic structure of the original sheet material was less than 99.8%, the ratio of the phase in the metallographic structure of the seam welded pipe was less than 99.5%, and in a flattening test and a pipe expansion test for the seam welded pipe, cracking occurred. In addition, stress corrosion cracking resistance was also deteriorated. When the ratio of the phase was 100%, workability and stress corrosion cracking resistance were improved and tensile strength, proof stress and elongation each had high values (refer to test Nos. 10, 25, 40, 55, 66, 73, 76, 206, 213 and the like).

[0204] In the seam welded pipe, even when the ratio of the phase in the constituent phase of the metallographic structure of the original sheet material was 100%, the ratio of the phase in the metallographic structure of the seam welded pipe was not 100% in some cases. When the ratio of the phase in the metallographic structure of the seam welded pipe was 99.5% or more, and 02()+()0.7, and a metallographic structure in which a phase having an area ratio of 0% to 0.3% and a phase having an area ratio of 0% to 0.5% are dispsersed in the a phase matrix is provided, in a flattening test and a pipe expansion test for the seam welded pipe, cracking did not occur. Also, in the seam welded pipe, the composition relational expression f1=[Zn]+5[Sn]2[Ni] was important and the composition relational expression f1=30 had one threshold (refer to test Nos. 73, 79, 206, 213 or the like).

[0205] When the value of the composition relational expression f2=[Zn]0.5[Sn]3[Ni] was greater than 28, stress corrosion cracking resistance were deteriorated. The composition relational expression f2=28 was a boundary value for determining whether the material could endure stress corrosion cracking in a severe environment, and as the numerical value decreased, stress corrosion cracking resistance was improved (refer to test Nos. 56, 80, 101, 102, 104, 105, 310, 313 and the like). In the CuZn alloys shown in Comparative Examples (Test No. 401 to 404), stress corrosion cracking was dependent on the amount of Zn. The amount of Zn of about 25 mass % was a boundary content for determining whether the material could endure stress corrosion cracking in a severe environment. As a result, the amount of Zn was almost equal to the value of the composition relational expression f2 of 28.

[0206] When the value of the composition relational expression f3 was less than 10, stress relaxation characteristics were deteriorated. The composition relational expression f3=10 was a boundary value for determining whether stress relaxation characteristics were good or not. The value of the composition relational expression f3 was in a range from 10 to 20, as the value increased. Stress relaxation characteristics were further improved and effective stress at a high temperature was more than 300 N/mm.sup.2 (refer to test Nos. 56, 80, 101 to 104, 106, 106A, 108, 307, 307A, 315 and the like).

[0207] While color fastness was improved due to the effect of incorporation of Ni and Sn, the value of the composition relational expression f4=0.7[Ni]+[Sn] was less than 1.2, and color fastness and stress relaxation characteristics were deteriorated. When the value of the composition relational expression f4 was 1.2 or greater or 1.4 or greater, color fastness and stress relaxation characteristics were further improved (refer to test Nos. 56, 110, 302, 309, 310 and the like).

[0208] When the value of the composition relational expression f5=[Ni]/[Sn] was less than 1.4, stress relaxation characteristics were deteriorated and bending workability was also deteriorated. When the value of the composition relational expression f5 was 1.6 or greater, stress relaxation characteristics were improved and when the value was 1.8 or greater, stress relaxation characteristics were further improved. It was thought that the composition relational expression f5=1.6 had one threshold for determining whether stress relaxation characteristics were good or not (refer to test Nos. 312, 103, 67 and the like). In addition, when the value of the f5=[Ni]/[Sn] was greater than 90, stress relaxation characteristics and color fastness were deteriorated and also strength was lowered. When the value of the f5=[Ni]/[Sn] was less than 12, stress relaxation characteristics and color fastness were improved and strength was increased (refer to test Nos. 110, 133, 321, 322 and the like).

[0209] In the case of incorporation of P, when the value of the composition relational expression f6=[Ni]/[P] satisfied 25f6750, or 30f6500, stress relaxation characteristics were further improved, bending workability was not impaired, and stress corrosion cracking resistance was improved (refer to test Nos. 56, 112, 108, 109, 128, 123, 134, 135, 306 and the like).

[0210] In addition, precipitates mainly composed of Ni and P, that is, compounds were formed and the average particle size of the precipitates was 10 nm to 70 nm. Slightly fine grains were formed (refer to test Nos. 46 to 60, 118 and the like).

[0211] When 0.0005 mass % or more and 0.2 mass % or less in total of at least one or more selected from Fe, Co, Mg, Mn, Ti, Zr, Cr, Si, Pb and rare earth elements, each contained in an amount of 0.0005 mass % or more and 0.05 mass % or less were incorporated, fine grains were obtained and strength was slightly increased (refer to test Nos. 118 to 127, 132 and the like). Particularly, even when the contents of Fe and Co were 0.001 mass %, fine precipitates were obtained, the average grain size was reduced, and tensile strength and proof stress were improved.

[0212] When the amount of Fe or Co of more than 0.05 mass % was incorporated, the particle size of the precipitates was smaller than 3 nm and the average grain size was smaller than 2 m. Thus, strength was increased, bending workability was deteriorated, and stress relaxation characteristics were slightly deteriorated (refer to test Nos. 318, 319 and the like).

[0213] As shown in Tables 27 and 28, regarding the antimicrobial properties of the alloys of the invention, when each additive element was within the composition range of the specification and each relational expressions were satisfied, excellent antimicrobial performance was exhibited. Further, the test pieces after the high temperature high humidity test at 60 C. and a humidity of 95% and the test pieces after the high temperature test at 120 maintained excellent antimicrobial performance. When the alloys were used for portions of a door knob or the like, touched by hands, and containers or the like, excellent antimicrobial properties (bactericidal properties) were achieved.

[0214] In addition, from the above evaluation results, regarding production processes and characteristics, the following was confirmed.

[0215] In actual production facilities, even when the number of annealing times including final annealing was 2 or 3 (processes A1-2, A2-2 and the like) or the method of annealing was a continuous annealing method or a batch type method (processes A2-1, A2-2 and the like), and the recovery heat treatment was a batch type method carried out in the laboratory or a continuous annealing method (processes A1-1, A1-2 and the like), strength, bending workability, color fastness, stress relaxation characteristics and stress corrosion cracking resistance, which are desired in the specification, were obtained.

[0216] The characteristics obtained from the actual production facilities were the almost the same as the characteristics of the process B of forming small pieces prepared in a laboratory (processes A2-1, B1-1 and the like).

[0217] In the laboratory test of small pieces, when final annealing or a recovery heat treatment was a continuous annealing method or a batch type method (processes B1-1 and B1-3), strength, bending workability, color fastness, stress relaxation characteristics and stress corrosion cracking resistance, which are desired in the specification, were obtained.

[0218] In the small sample pieces of the process B, the characteristics of the alloys of the invention prepared by carrying out annealing one time, carrying out only final annealing without annealing, or repeatedly carrying out annealing and cold rolling without a hot rolling process were almost the same (processes B1-1, B2-1 and B3-1).

[0219] In addition, when the recovery heat treatment was carried out, stress relaxation characteristics were improved and the ratio of proof stress/tensile strength was increased and the value was close to 1.0 (processes A2-2, A2-4 and the like).

[0220] The processes C1 and C1A were carried out by carrying out melting and casting in a laboratory using facilities of the laboratory, and the final heat treatment was a batch type method and a continuous heat treatment method. In the alloys of the invention prepared in both processes, for stress relaxation characteristics, a continuous annealing method was more effective but for the other characteristics were almost the same.

[0221] Under the conditions of a heat treatment (300 C.0.07 minutes) and (250 C.0.15 minutes) on the assumption of molten Sn plating or the like, compared to conditions for other recovery heat treatments including a recovery heat treatment in an actual apparatus, strength was lightly high, and the value of elongation was low, and the values of stress relaxation characteristics and effective stress at 150 C. were deteriorated. The target characteristics could be achieved. This heat treatment can be replaced by the recovery heat treatment by carrying out molten Sn plating or the like, or the recovery heat treatment can be omitted.

[0222] The value of the heat treatment conditional expression It1 was high, the final working rate was 25% in the processes A2-5 and 2-6, and strength was slightly high. However, bending workability and stress corrosion cracking resistance were maintained and were satisfactory.

[0223] Regarding stress relaxation characteristics, the case in which final annealing was carried out by a continuous high temperature short time annealing method was better compared to the case in which a batch type annealing method was carried out. Particularly, in the case of incorporation of P, when annealing was carried out by a high temperature short time annealing method, good stress relaxation characteristics were obtained. In addition, when the index It1 was slightly high, satisfactory stress relaxation characteristics were obtained (processes A1-4, A2-2, A2-5 and A2-7). It was thought that the stress relaxation characteristics were affected by balance between Ni and P in the solid solution state and precipitates of Ni and P.

[0224] In the process A2-7 in which the value of It1 was close to the upper limit, irrespective of a high rolling reduction, compared to the process A2-2, strength was the same or lowered, and stress relaxation characteristics were saturated. Bending workability was slightly deteriorated. In the process A2-8 in which the value of It1 was greater than the upper limit, the average grain size was large and irrespective of a high rolling reduction, strength was low and the orientation of material strength was generated. Thus, bending workability, stress relaxation characteristics and stress corrosion cracking resistance were deteriorated. In the process A2-9, when the temperature was excessively raised by batch type annealing, the grains were enlarged and remarkable mixed grains were formed. Therefore, bending workability was deteriorated, the orientation of material strength, that is, the values of YS.sub.P/TS.sub.P and YS.sub.P/YS.sub.O were smaller than 0.9, and stress relaxation characteristics and stress corrosion cracking resistance were deteriorated. In the process A2-10, since the value of It1 was smaller than a predetermined value, a metallographic structure including uncrystallized portions was formed. Thus, although strength was high, bending workability, stress relaxation characteristics and stress corrosion cracking resistance were deteriorated.

[0225] There was almost no difference in the recovery heat treatment under batch type conditions (300 C., holding time: 30 minutes) and continuous high temperature short time conditions (450 C.0.05 minutes) (processes A2-1, A2-2, A1-1, A1-2 and the like).

[0226] As described above, when an element such as Ni or Sn are suitably or most suitably contained in the copper alloy containing a high concentration of Zn, the alloy can be formed into a sheet material and a seam welded pipe having excellent color fastness, high strength, good bending workability, satisfactory color fastness, stress relaxation characteristics, stress corrosion cracking resistance at a high temperature and high humidity or at a high temperature, and high antimicrobial performance. Accordingly, excellent cost performance, a reduction in thickness and a compact body, which are required in these days, can be obtained, and a severe environment including a final product that endures a high temperature and a high humidity, further, a multi-functional final product with high performance and high functionality can be obtained. Particularly, when plating is carried out to solve color change or stress corrosion problems, the plating can be omitted and high conductivity or antimicrobial and bactericidal performance of a copper alloy can be continuously exhibited. Specifically, since strength is high, stress relaxation characteristics are excellent, and the alloy can endure a severe use environment, the alloy is suitable for connectors, terminals, relays, switches, springs, sockets and the like used in electronic and electric apparatus components and automobile components. In addition, since strength is high, the alloy can endure a severe use environment, antimicrobial performance is high, and the high antimicrobial properties can be maintained, the alloy is a suitable material for construction metal fittings and members such as handrails, door handles, inner wall materials or the like, medical appliances and containers, water supply and drain facilities, apparatuses and containers, decoration members, and the like.

[0227] Further, when conductivity is 14% IACS or more and 25% IACS or less and the metallographic structure is composed of an phase, further excellent strength and balance between strength and bending workability are obtained and stress relaxation characteristics, particularly, effective stress at 150 C. is increased. Thus, the alloy is a more suitable material for connectors, terminals, relays, switches, springs, sockets and the like used in electronic and electric apparatus components and automobile components used in a severe environment.

INDUSTRIAL APPLICABILITY

[0228] According to the copper alloys of the present invention, excellent cost performance, a small density, and a conductivity higher than the conductivity of phosphorus bronze or nickel silver can be provided and high strength, balance between strength and elongation and bending workability, stress relaxation characteristics, stress corrosion cracking resistance, color fastness, and antimicrobial properties can be improved.

COPPER ALLOY

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C21D8/0263

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C22C9/04

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Abstract

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