Components For Drinking Water Pipes, And Method For Manufacturing Same

Abstract

A CuZnSi alloy having low lead content is described, along with components such as plumbing fittings suitable for drinking water pipes, and methods of manufacturing same are described.

Claims

1. A CuZnSi alloy consisting of the following components in weight percent: $11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;0.1\mathrm{Mn}0.2;$ wherein the sum of the weight percentage of Zn, [Zn], and ten times the weight percentage of Si, [Si], amounts to a combined weight percentage Q, where Q=[Zn]+(10[Si]), wherein 36Q48; wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; wherein the CuZnSi alloy comprises no more than 0.03 wt % P; wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and wherein the balance is copper said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more and said alloy having an elongation at fracture of 30% or more as determined in accordance with ISO6892-1:2009.

2. The CuZnSi alloy according to claim 1, wherein the CuZnSi alloy comprises in weight percent: 2.5Si3.5.

3. The CuZnSi alloy according to claim 1, wherein 2.5Si3.2; and where 36Q47.

4. The CuZnSi alloy according to claim 1, wherein 2.7Si3.5; and where 37Q48.

5. The CuZnSi alloy according to claim 1, wherein 11.5Zn13.0.

6. The CuZnSi alloy according to claim 1, wherein said CuZnSi alloy is free of As and/or Sb.

7. A component for drinking-water pipes comprising the CuZnSi alloy as claimed in claim 1.

8. (canceled)

9. The component for drinking-water pipes according to claim 7, wherein said alloy has a density in the range of from 8.0 kg/m.sup.3 to 8.29 kg/m.sup.3.

10. A method for manufacturing a component for drinking-water pipes comprising: (i) providing a CuZnSi alloy consisting of the following in weight percent: $11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;0.1\mathrm{Mn}0.2;$ wherein the sum of the weight percentage of Zn, [Zn], and ten times the weight percentage of Si, [Si], amounts to a combined weight percentage Q, where Q=[Zn]+(10[Si]), wherein 36Q48; wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; wherein the CuZnSi alloy comprises no more than 0.03 wt % P; wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and wherein the balance is copper; said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; and said alloy having an elongation at fracture of 30% or more, as determined in accordance with ISO6892-1:2009; and (ii) processing said alloy to form said component.

11. The method of claim 10, wherein step (ii) includes continuous casting said alloy, and/or wherein step (ii) includes one or more metal forming steps.

12. The method of claim 10, wherein step (ii) includes gravity casting said alloy.

13. The method of claim 10, wherein step (ii) includes one or more metal forming steps.

14. The method of claim 10, wherein step (ii) further includes one or more machining steps.

15. The method of claim 10, wherein the CuZnSi alloy has a tensile strength as determined in accordance with ISO 6892-1:2009 of 350 MPa or more.

16. The method of claim 10, wherein the CuZnSi alloy has a density in the range of from 8.0 kg/m.sup.3 to 8.29 kg/m.sup.3.

Description

DETAILED DESCRIPTION

[0119] As outlined above, disclosed herein is a CuZnSi alloy comprising, consisting essentially of, or consisting of the following components in weight percent:

[00007]$11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;$ [0120] 0.1Mn0.2, such as 0.1Mn0.15, preferably 0.10Mn0.14; [0121] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q, [0122] where Q=[Zn]+(10[Si]), [0123] wherein 36Q48; [0124] wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; [0125] wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; [0126] wherein the CuZnSi alloy comprises no more than 0.03 wt % P; [0127] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0128] wherein the balance is copper, for example, 82.0Cu86.3, preferably 82.0Cu85.0, for example 82.2Cu85.0, or 82.5Cu84.5, such as 83.0Cu84.5; [0129] said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; preferably 400 MPa or more, and [0130] said alloy having an elongation at fracture of 25% or more, preferably 30% or more, more preferably 40% or more as determined in accordance with ISO6892-1:2009.

[0131] The CuZnSi alloy is particularly suitable for manufacture of components such as plumbing fittings, for example, components for drinking water pipes i.e. pipes suitable for conveying drinking water or other media for human consumption for example, coupling parts, angular parts, elbow parts, T-piece parts, distributor parts, fittings and valves. Of course, the components may also be used in other plumbing settings, for example in central heating, ventilation or air-conditioning systems.

[0132] Advantageously, the components are lead free and have low ion migration into media such as drinking water which is conveyed through the components.

[0133] The zinc content of 11.0 wt % to 13.0 wt % influences elongation and tensile strength. If the zinc content is lower than about 11 wt %, the elongation is reduced. If the zinc content exceeds about 13 wt % the tensile strength deteriorates. In some embodiments, the zinc content is in the range of from 11.5 wt % to 13.0 wt %, such as from 12.0 wt % to 13.0 wt %.

[0134] The silicon content of 2.5 wt % to 3.7 wt % influences corrosion resistance, castability, and abrasion resistance. The corrosion rate may be between 0.02 and 0.002 mm/year as determined in accordance with ISO 16151:2018. If the silicon content is lower than about 2.5 wt %, these properties are reduced. If the silicon content exceeds about 3.7 wt % these properties deteriorate. In some embodiments, the silicon content is in the range of from 2.5 wt % to 3.5 wt %.

[0135] Importantly, the relationship between the zinc content and the silicon content significantly influences tensile strength and elongation when the alloy is processed under different processing conditions.

[0136] For example, the alloy of the present invention when processed in a continuous casting or metal forming process has an optimal relationship between the amount of zinc and silicon which is defined by Q: [0137] where Q=[Zn]+(10[Si]), and wherein 2.5Si3.5, such as from 2.5Si3.2; and where 36Q47, preferably 38Q42.

[0138] In a continuous casting or metal forming process if Q is less than about 36 a reduction in tensile strength is observed, whereas if Q is greater than about 47, a reduction in elongation is observed. Advantageously when Q is in the range of from about 38 wt % to about 42 wt % optimal tensile strength and elongation are achieved for components as described in the present invention.

[0139] Accordingly, one aspect of the present invention provides components for drinking water pipes, namely valves and fittings for same, manufactured by continuous casting or metal forming a CuZnSi alloy comprising the following components in weight percent:

[00008]$11.\mathrm{Zn}13.2.5\mathrm{Si}3.50.1\mathrm{Fe}0.5$ [0140] 0.1Mn0.2, e.g. 0.1Mn0.15, preferably in the range: 0.10Mn0.14; [0141] wherein the sum of the weight percentage of Zn and ten times the weight percentage of Si amounts to a combined weight percentage Q, [0142] where Q=[Zn]+(10[Si]), [0143] wherein 36Q47, preferably 38Q42, [0144] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0145] wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb, preferably no more than 0.05 wt % Pb; [0146] wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; [0147] wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; [0148] wherein the CuZnSi alloy comprises no more than 0.03 wt % P; [0149] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0150] wherein the balance is copper, for example, 82.0Cu86.3, preferably 82.0Cu85.0, for example 82.2Cu85.0, or 82.5Cu84.5, such as 83.0Cu84.5; [0151] said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; preferably 400 MPa or more, and [0152] said alloy having an elongation at fracture of 25% or more, preferably 30% or more, more preferably 40% or more as determined in accordance with ISO6892-1:2009.

[0153] When the alloy of the present invention is processed in a gravity casting process, the optimal relationship between the amount of zinc and silicon is defined by Q: [0154] where Q=[Zn]+(10[Si]), and wherein 2.7Si3.5, such 2.8Si3.2; and where 37Q48, preferably 40Q46.

[0155] In a gravity casting process, such as a sand casting process or a die casting process, if Q is less than about 37 a reduction in tensile strength is observed, whereas if Q is greater than about 48, a reduction in elongation is observed. Advantageously when Q is in the range of from about 40 wt % to about 46 wt %, optimal elongation and tensile strength is achieved for gravity castings.

[0156] Accordingly, another aspect of the invention provides components for drinking water pipes, namely valves and fittings for same, manufactured by gravity casting, such as sand casting or die casting, a CuZnSi alloy of the present invention comprising the following components in weight percent:

[00009]$11.\mathrm{Zn}13.2.7\mathrm{Si}3.50.1\mathrm{Fe}0.5$ [0157] 0.1Mn0.2, e.g. 0.1Mn0.15, preferably in the range: 0.10Mn0.14; [0158] wherein the sum of the weight percentage of Zn and ten times the weight percentage of Si amounts to a combined weight percentage Q, [0159] where Q=[Zn]+(10[Si]), [0160] wherein 37Q48, preferably 40Q46, [0161] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0162] wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb.

[0163] The CuZnSi alloy of the present invention comprises iron in an amount of from 0.1 wt % to 0.5 wt %. When the amount of iron is lower than about 0.1 wt % cracking proneness when heated increases, ductility reduces and the fine-grained uniform structure is not observed. If the amount of iron is greater than about 0.5 wt % cracking proneness when heated increases, ductility reduces and the fine-grained uniform structure is not observed.

[0164] The CuZnSi alloy of the present invention comprises manganese in an amount of 0.1 wt % to 0.2 wt %.

[0165] When the amount of manganese is less than about 0.1 wt % a reduction in corrosion resistance is observed. If the amount of manganese is greater than about 0.2 wt % a reduction in corrosion resistance is observed. The amount of manganese is suitably in the range of from 0.1 wt % to 0.15 wt %, preferably in the range of from 0.1 wt % to 0.14 wt %. Elongation at fracture is advantageously further enhanced when the amount of manganese is within this range.

[0166] Suitably, the content of the four main alloying elements i.e. Zn, Si, Fe and Mn, and excluding copper is between 13.7 and 16.9 wt %, such as from 13.7 and 16.6 wt % for components manufactured using continuous casting or metal forming.

[0167] Suitably, the content of the four main alloying elements i.e. Zn, Si, Fe and Mn, and excluding copper is between 13.9 and 17.3 wt %, such as from 14.1 to 17.3 wt % or 13.9 and 17.2 wt % for components manufactured using gravity casting, such as sand casting or die casting.

[0168] The components of the invention are CuZnSi alloy casting components, such as CuZnSi alloy: continuous castings, gravity castings, sand castings, or die castings.

[0169] Suitably, the methods described herein may include one or more annealing steps. Advantageously, such annealing can enhance the ductility of the CuZnSi alloy, and components made therefrom. For example, the CuZnSi alloy may be annealed by heating to a temperature in the range of from 700 to 900 C.

[0170] For the purpose of clarity and concise description, features are described herein as part of the same or separate embodiments, however, it will be appreciated that the scope of the invention may include embodiments having combinations of all or some of the features described.

[0171] It is appreciated that the weight of the components of the alloys of the invention add up to 100 wt %, thus for example, when a composition specifies the balance is copper, this means that the remainder of the composition to make up 100 wt % is copper i.e. the balance is copper up to 100 wt %.

[0172] The invention will be more readily appreciated by a review of the examples, which follow. The examples are not limiting on the scope of the invention, which is defined in the claims.

EMBODIMENTS

1. Components for drinking-water pipes, namely valves and fittings for same, manufactured from a CuZnSi alloy comprising the following components in weight percent: [0173] 80Cu88, preferably 81.0Cu86.5

[00010]$11.\mathrm{Zn}13.2.4\mathrm{Si}4.10.1\mathrm{Fe}0.5$ [0174] optionally, 0.1Mn0.2; [0175] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q, [0176] where Q=[Zn]+(10[Si]), [0177] wherein 35Q52; [0178] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0179] wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb.
2. A method for manufacturing components for drinking-water pipes, namely valves and fittings for same, comprising: [0180] (i) Providing a CuZnSi alloy comprising the following components in weight percent: [0181] 80Cu88, preferably 81.0Cu86.5,

[00011]$11.\mathrm{Zn}13.2.4\mathrm{Si}4.10.1\mathrm{Fe}0.5$ [0182] optionally, 0.1Mn0.2; [0183] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q: [0184] where Q=[Zn]+(10[Si]) [0185] wherein 35Q52; and [0186] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0187] wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0188] (ii) processing said alloy to form said components.
3. The method of embodiment 2, wherein step (ii) includes continuous casting said alloy, and/or wherein step (ii) includes one or more metal forming steps.
4. The method of embodiment 2, wherein step (ii) includes gravity casting said alloy, for example sand casting or die casting said alloy.
5. The method of embodiment 2, wherein step (ii) includes one or more metal forming steps, for example forging or rolling said alloy.
6. The method of any one of embodiment 2 to 5, wherein step (ii) further includes one or more machining steps.
7. The method of any one of embodiments 2 to 6, wherein the CuZnSi alloy comprises in weight percent:

[00012]$80.5\mathrm{Cu}87,$ [0189] preferably 81.0Cu86.5, [0190] more preferably 81.5Cu86.3, [0191] even more preferably 82.0Cu86.0, such as 82.0Cu85.0.
8. The method of any one of embodiments 2 to 7, wherein the CuZnSi alloy comprises in weight percent: [0192] 2.5Si3.7, preferably 2.5Si3.5.
9. The method of any one of embodiments 2 to 8, wherein step (ii) involves heating the CuZnSi alloy to a temperature in the range of from 800 to 1300 C., in one or more processing steps.
10. The method of embodiment 3, wherein the CuZnSi alloy comprises in weight percent: [0193] 2.5Si3.5, such as from 2.5Si3.2; and [0194] where 36Q47, preferably 38Q45, such as from 38Q42.
11. The method of embodiment 4, wherein the CuZnSi alloy comprises in weight percent: [0195] 2.5Si3.7, such as from 2.7Si3.5; and [0196] where 37Q480, preferably 40Q46.
12. The method of any one of embodiments 2 to 11, wherein the CuZnSi alloy has a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more, preferably 350 MPa or more, even more preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more.
13. The method of any one of embodiments 2 to 12, wherein the CuZnSi alloy has an elongation of 25% or more as determined in accordance with ISO 6892-1:2009.
14. The method of any one of embodiments 2 to 13, wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni.
15. The method of any one of embodiments 2 to 14, wherein the CuZnSi alloy comprises up to 0.2 wt % Al.
16. The method of any one of embodiments 2 to 15, wherein the CuZnSi alloy comprises up to 0.03 wt % P.
17. The method of any one of embodiments 2 to 16, wherein the CuZnSi alloy is free of As, Sb.
18. A CuZnSi alloy comprising, consisting essentially of, or consisting of the following components in weight percent:

[00013]$11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;$ [0197] 0.1Mn0.2, e.g. 0.1Mn0.15, preferably in the range: 0.10Mn0.14; [0198] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q, [0199] where Q=[Zn]+(10[Si]), [0200] wherein 36Q48; [0201] wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; [0202] wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; [0203] wherein the CuZnSi alloy comprises no more than 0.03 wt % P; [0204] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0205] wherein the balance is copper, for example, 82.0Cu86.3, suitably 82.0Cu86.0, such as 82.0Cu85.8, preferably 82.0Cu85.0, for example 82.2Cu85.0, or 82.5Cu84.5, such as 83.0Cu84.5; [0206] said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; preferably 400 MPa or more, and [0207] said alloy having an elongation at fracture of 25% or more, preferably 30% or more, more preferably 40% or more as determined in accordance with IS06892-1:2009.
19. The CuZnSi alloy according to claim 18, wherein the CuZnSi alloy comprises in weight percent:

[00014]$2.5\mathrm{Si}3.5.$

20. The CuZnSi alloy according to claim 19, wherein 2.5Si3.2; and [0208] where 36Q47, preferably 38Q45, such as from 38Q42.
21. The CuZnSi alloy according to claim 19, wherein 2.7Si3.5; and [0209] where 37Q48, preferably 40Q46, such as from 40Q44.
22. The CuZnSi alloy according to any one of embodiments 18 to 21, wherein 11.5Zn13.0, such as 12.0Zn13.0.
23. The CuZnSi alloy according to any one of embodiments 18 to 22, wherein said CuZnSi alloy is free of As and/or Sb.
24. Components for drinking-water pipes, namely valves and fittings for same, manufactured from a CuZnSi alloy comprising, consisting essentially of or consisting of the following in weight percent:

[00015]$11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;$ [0210] 0.1Mn0.2 e.g. 0.1Mn0.15, preferably 0.10Mn0.14; [0211] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q, [0212] where Q=[Zn]+(10[Si]), [0213] wherein 36Q48; [0214] wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; [0215] wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; [0216] wherein the CuZnSi alloy comprises no more than 0.03 wt % P; [0217] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0218] wherein the balance is copper, for example, 82.0Cu86.3, suitably 82.0Cu86.0, such as 82.0Cu85.8, preferably 82.0Cu85.0, for example 82.2Cu85.0, or 82.5Cu84.5, such as 83.0Cu84.5; [0219] said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; and [0220] said alloy having an elongation at fracture of 25% or more, preferably 30% or more, more preferably 40% or more as determined in accordance with ISO6892-1:2009.
25. Components for drinking-water pipes according to embodiment 24, wherein said components are manufactured from the CuZnSi alloy according to any one of claims 2 to 6.
26. Components for drinking-water pipes according to embodiment 24 or 25, wherein said alloy has a true solid state density in the range of from 8.0 kg/m.sup.3 to 8.29 kg/m.sup.3, preferably from 8.0 to 8.28 kg/m.sup.3, suitably from 8.18 to 8.28 kg/m.sup.3.
27. A method for manufacturing components for drinking-water pipes, namely valves and fittings for same, comprising: [0221] (i) Providing a CuZnSi alloy comprising, consisting essentially of, or consisting of the following in weight percent:

[00016]$11.\mathrm{Zn}13.;2.5\mathrm{Si}3.7;0.1\mathrm{Fe}0.5;$ [0222] 0.1Mn0.2, e.g. 0.1Mn0.15, preferably 0.1Mn0.14; [0223] wherein the sum of the weight percentage of Zn ([Zn]) and ten times the weight percentage of Si ([Si]) amounts to a combined weight percentage Q, [0224] where Q=[Zn]+(10[Si]), [0225] wherein 36Q48; [0226] wherein the CuZnSi alloy comprises in weight percent no more than 0.05% Ni; [0227] wherein the CuZnSi alloy comprises no more than 0.2 wt % Al; [0228] wherein the CuZnSi alloy comprises no more than 0.03 wt % P; [0229] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, wherein said impurities contain no more than 0.2 wt % Sn, and no more than 0.06 wt % Pb; and [0230] wherein the balance is copper, for example, 82.0Cu86.3, suitably 82.0Cu86.0, such as 82.0Cu85.8, preferably 82.0Cu85.0, for example 82.2Cu85.0, or 82.5Cu84.5, such as 83.0Cu84.5; [0231] said CuZnSi alloy having a tensile strength as determined in accordance with ISO 6892-1:2009 of 300 MPa or more; and [0232] said alloy having an elongation at fracture of 25% or more, preferably 30% or more, more preferably 40% or more as determined in accordance with ISO6892-1:2009; and [0233] (ii) Processing said alloy to form said components.
28. The method of embodiment 27, wherein step (ii) includes continuous casting said alloy, and/or wherein step (ii) includes one or more metal forming steps.
29. The method of embodiment 27, wherein step (ii) includes gravity casting said alloy, for example sand casting or die casting said alloy.
30. The method of embodiment 27, wherein step (ii) includes one or more metal forming steps, for example forging or rolling said alloy.
31. The method of any one of embodiments 27 to 30, wherein step (ii) further includes one or more machining steps.
32. The method of any one of embodiments 27 to 31, wherein the CuZnSi alloy has a tensile strength as determined in accordance with ISO 6892-1:2009 of 350 MPa or more, preferably 380 MPa or more, even more preferably 400 MPa or more, such as 450 MPa or more.
33. The method of any one of claims 27 to 32, wherein the CuZnSi alloy has a true solid state density in the range of from 8.0 kg/m.sup.3 to 8.29 kg/m.sup.3, preferably from 8.0 to 8.28 kg/m.sup.3, suitably from 8.18 to 8.28 kg/m.sup.3, when determined in accordance with BS ISO 12154.

EXAMPLES

Example 1

[0234] A rod was continuously cast from a CuZnSi alloy of the present invention comprising:

[00017]$81.\mathrm{Cu}86.511.5\mathrm{Zn}13.2.9\mathrm{Si}3.40.1\mathrm{Fe}0.50.1\mathrm{Mn}0.2;$ [0235] wherein 42Q47; [0236] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0237] wherein said impurities contain no more than 0.06 wt % Sn, and no more than 0.06 wt % Pb.

[0238] The composition of Example 1 contained 0.010Ni0.025

[0239] The composition of Example 1 was free of Bi, Ag, Te and As.

[0240] The amount of copper was in the range of from 82.0 to 85.0 wt % based on the total weight of the alloy.

[0241] Ingots having an alloy composition as specified above, were loaded into a furnace capable of smelting and casting. The alloy was heated to a temperature in the range of from 1000 to 1200 C., and the smelt is cast through graphite dies with copper coolers. The liquid metal is cooled and drawn as a continuous rod or tube. The tubes are cut to size and are conveyed to a stamping station and/or a machining station.

[0242] For a stamping process, the continuously cast rod is cut into billets of a particular size (size varies depending on the amount of material required to manufacture the end component part). The billets may then be heated and forged. After forging the stamp is cooled and trimmed. The stamp may optionally be annealed, for example by heating to a temperature in the range of from 700 to 900 C. The stamp is cleaned and then sent to a machining station.

[0243] The continuously cast CuZnSi alloy of Example 1 was employed to manufacture components for drinking water pipes in a process involving stamping and machining steps.

[0244] The tensile strength and elongation of the CuZnSi alloy was assessed in accordance with ISO 6892-1:2009 on a Hounsfield tensometer:

Measurement Parameters:

[0245] Elongation sensor type: extensometer

[0246] Measuring length of extensometer (Le): 50 mm

[0247] Force measuring range: 50 kN

Environmental Monitoring:

[0248] Humidity: 50.0%

[0249] Temperature: 22.0 C.

Sample Data:

[0250] Sample initial dimensionsD0: 9.50 mm S0: 70.88 mm.sup.2

[0251] Initial measuring length (L0): 50.00 mm

[0252] Parallel part length (Lc): 55.00 mm

Sample Results:

[0253] Tensile strength Rm: 488.2 MPa

[0254] % Elongation at fracture (Agt): 51,214%

[0255] A cross section of the continuously cast rod of Example 1 is shown in FIG. 1.

[0256] FIG. 2 shows a magnified image of FIG. 1. Captured using 5XJP-6A Metallurgical Microscope20 lens Microscope camera DLT-Cam PRO with samples from a 26 rod in an Acid mixture: HCl (20%): H.sub.2NO.sub.3 (20%): H.sub.2SO.sub.4 (20%)1: 2.

[0257] FIG. 3 shows the ends of the continuously cast CuZnSi alloy rod of example 1 having been extended to break in the extensometer.

Example 2

[0258] A rod was continuously cast from a CuZnSi alloy of the present invention having the following composition:

[00018]$82\mathrm{Cu}86.512.\mathrm{Zn}13.2.7\mathrm{Si}3.10.1\mathrm{Fe}0.50.1\mathrm{Mn}0.2;$ [0259] wherein 38Q44; [0260] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0261] wherein said impurities contain no more than 0.06 wt % Sn, and no more than 0.05 wt % Pb.

[0262] The composition of Example 2 contained 0.010Ni0.025.

[0263] The composition of Example 2 was free of Bi, Ag, Te and As.

[0264] The amount of copper was in the range of from 82.0 to 85.0 wt % based on the total weight of the alloy.

[0265] The continuously cast rod was processed as descried in Example 1.

[0266] The tensile strength and elongation of a continuously cast CuZnSi alloy from Example 2 was assessed in accordance with ISO 6892-1:2009 on a Hounsfield tensometer:

Measurement Parameters:

[0267] Elongation sensor type: extensometer

[0268] Measuring length of the extensometer (Le): 50 mm

[0269] Force measuring range: 50 kN

Environmental Monitoring:

[0270] Humidity: 50.0%

[0271] Temperature: 20.0 C.

Sample Data

[0272] Sample initial dimensionsD0: 9.48 mm S0: 70.58 mm2

[0273] Initial measuring length (L0): 50.00 mm

[0274] Parallel part length (Lc): 55.00 mm

Sample Results:

[0275] Tensile strength (Rm): 454.0 MPa

[0276] % Elongation at fracture (Agt): 43,036%

[0277] FIG. 4 shows a cross section of a continuously cast rod according to Example 2.

[0278] It was surprisingly found that the CuZnSi alloy of the invention when continuously cast, had significantly superior tensile strengths and elongation at fracture properties in comparison to prior art continuous castings. For example, continuous castings had a tensile strength of 380 MPa or more, preferably 400 MPa or more, even more preferably 450 MPa or more as determined in accordance with ISO 6892-1:2009. In addition, continuous castings of the present invention had a percentage elongation at fracture of 25% or more, preferably 30% or more, even more preferably 40% or more as determined in accordance with ISO 6892-1:2009. For example, continuous castings had a percentage elongation at fracture in the range of 25% to 65%, such as from 35% to 60% as determined in accordance with ISO 6892-1:2009. Suitably, the CuZnSi alloy of the present invention and continuous castings made therefrom, have a tensile strength of 380 MPa or more, and an elongation at fracture in the range of from 25% to 65%, preferably, the tensile strength is in the range of from 380 MPa to 650 MPa, preferably from 400 MPa to 600, such as from 450 MPa to 600 MPa, and the elongation at fracture is 25% to 65%, such as 35% to 60% as determined in accordance with ISO 6892-1:2009.

Example 3

[0279] A rod was gravity die cast from a CuZnSi alloy of the present invention having the following composition:

[00019]$82.5\mathrm{Cu}84.511.5\mathrm{Zn}12.33.3\mathrm{Si}3.50.1\mathrm{Fe}0.50.1\mathrm{Mn}0.2;$ [0280] wherein 40Q44; [0281] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0282] wherein said impurities contain no more than 0.06 wt % Sn, and no more than 0.06 wt % Pb.

[0283] The composition of Example 3 contained 0.010Ni0.025.

[0284] The composition of Example 3 was free of Bi, Ag and As.

[0285] Ingots having an alloy composition as specified above, were loaded into a furnace capable of smelting and casting. The alloy was heated to a temperature in the range offrom 1000 to 1300 C., suitably between 115 and 1300 C.

[0286] In this step chemical composition may be monitored and controlled to ensure the composition is maintained. For example should some elements (e.g. Zn and P) evaporate or go to slag, they must be replaced to keep the required composition of the present invention. The smelted metal is transported and poured into a holding furnace, and subsequently cast into a die casting. The liquid metal is cooled in the die (for example with air cooling or water cooling) and once solidified the die is opened and the rod is released. Advantageously, the CuZnSi alloy of the present invention has enhanced tensile strength and elongation properties in comparison to prior art CuZnSi alloys. The enhanced properties increase the processing ease of the alloy.

[0287] The properties of the die casting were assessed in accordance with ISO 6892-1:2009 on a Hounsfield tensometer, as outlined above for Examples 1 and 2.

[0288] The casting had a tensile strength of >380 MPa, and an elongation at fracture of >25% as determined in accordance with ISO 6892-1:2009.

[0289] Advantageously, the CuZnSi alloys of the examples had a manganese content in the range: 0.10Mn0.14; the alloys of the invention advantageously have even further enhanced elongation when the amount of manganese is in this preferred range.

[0290] Advantageously, the true solid state density of the CuZnSi alloys of the examples described herein was in the range of from 8.18 to 8.28 Kg/m.sup.3 as measured in accordance with BS ISO 12154. BS ISO 12154 defines true solid state density as the ratio of the sample mass to the volume of the compact solid skeleton of the sample which excludes the volume of open and closed pores or internal voids and also interparticle voids as in the case of granulated or highly dispersed samples.

COMPARATIVE EXAMPLES

[0291] A rod was cast from a CuZnSi alloy having the following compositions:

TABLE-US-00003 CE1 CE2 CE3 Element wt % Element wt % Element wt % Cu 82.060 Cu 85.620 Cu 82.730 Sn 0.038 Sn 0.043 Sn 0.082 Zn 14.137 Zn 9.792 Zn 12.353 Pb 0.136 Pb 0.073 Pb 0.095 Ni 0.012 Ni 0.016 Ni 0.015 Sb 0.026 Sb 0.066 Sb 0.058 Al. 0.008 Al. 0.007 Al. 0.005 As 0.006 As 0.006 As 0.001 Fe 0.118 Fe 0.124 Fe 0.269 Mn 0.092 Mn 0.092 Mn 0.153 P 0.002 P 0.000 P 0.002 S 0.004 S 0.006 S 0.003 Si 3.359 Si 4.157 Si 4.227 Bi 0.001 Bi 0.000 Bi 0.006 Ag 0.000 Ag 0.000 Ag 0.000 Q (wt %) 47.7 Q (wt %) 51.36 Q (wt %) 54.6 Tensile 134.1 Tensile 322.7 Tensile 391.9 strength strength strength (MPa) (MPa) (MPa) % 6.05 % % 7.28 Elongation Elongation Elongation at fracture at fracture at fracture

[0292] CE1 comprises >13 wt % Zn, and despite containing 0.136 wt % Pb, has low tensile strength and low.

[0293] CE2 comprises <11 wt % Zn, >4.1 wt % Si and had an excellent tensile strength. However, the alloy was very brittle (see FIG. 7). Hence, suitable the alloy of CE2 did not have suitable elongation properties.

[0294] CE3 comprises >4.1 wt % Si and has a Q of >52 wt %. The tensile strength was excellent however, the elongation was not suitable.

Comparative Example 4 (CE4)

[0295] A rod was gravity die cast from a CuZnSi alloy of the present invention having the following composition:

[00020]$82\mathrm{Cu}86.511.5\mathrm{Zn}12.33.6\mathrm{Si}4.10.1\mathrm{Fe}0.50.1\mathrm{Mn}0.2;$ [0296] wherein 48Q51; [0297] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0298] wherein said impurities contain no more than 0.06 wt % Sn, and no more than 0.06 wt % Pb.

[0299] The composition of Example 3 contained 0.010Ni0.025.

[0300] The composition of Example 3 was free of Bi, Ag and As.

[0301] The properties of the die casting were assessed in accordance with ISO 6892-1:2009 on a Hounsfield tensometer, as outlined above for Examples 1 and 2.

[0302] The CuZnSi alloy of comparative example 4 had a tensile strength of 363.6 MPa, and an elongation at fracture of 16%. The CuZnSi alloy of comparative example 4 had a Q of approximately 50.

[0303] FIG. 5 shows a cross section of the rod cast in Comparative Example 4. Advantageously, the grain is uniform/homogenous, however, the elongation of the rod cast in comparative example 4, was 16%. FIG. 6 shows the ends of the die cast CuZnSi alloy rod of comparative example 4 having been extended to break in the extensometer.

[0304] Thus while the alloy of comparative example 4 had excellent tensile strength, the elongation at fracture was less than 25%. Advantageously, CuZnSi alloys according to the invention which have Q in the range: 36Q48, and for gravity cast CuZnSi alloys of the invention preferably 40Q46, and for continuous cast CuZnSi alloys of the invention preferably 38Q45, have elongation at fracture of 25% or more as determined in accordance with ISO6892-1:2009.

Example 4

[0305] A rod was continuously cast from a CuZnSi alloy of the present invention as described in Examples 1 and 2, the CuZnSi alloy of example 4 had the following composition:

[00021]$82.5\mathrm{Cu}84.512.5\mathrm{Zn}13.2.6\mathrm{Si}2.90.1\mathrm{Fe}0.50.1\mathrm{Mn}0.15;$ [0306] wherein 38.5Q42; [0307] wherein the alloy includes unavoidable impurities in an amount of 0.53 wt % or less, [0308] wherein said impurities contain no more than 0.06 wt % Sn, and no more than 0.06 wt % Pb.

[0309] The composition of Example 4 contained 0.010Ni0.025

[0310] The composition of Example 1 was free of Bi, Ag, Te and As.

[0311] A comparison of the mechanical properties of a CuZnSi alloy of the present invention versus (Example 4) and C87800 is provided in Table 1:

TABLE-US-00004 TABLE 1 Mechanical Properties Tensile Elongation Hardness strength at break Brinell C87800 460 Mpa 25% 134 CuZnSi alloy (Example 4) 450 Mpa 40% 107

[0312] Advantageously, the CuZnSi alloy of the present invention has greater ductility, and in particular has a greater elongation at fracture as determined in accordance with IS06892-1:2009.

[0313] A comparison of the physical properties of a CuZnSi of the present invention and C87800 is provided in Table 2:

TABLE-US-00005 TABLE 2 Physical Properties Melting Melting Thermal Specific Point- Point- Conductivity Heat Liquidus Solidus [W m.sup.1 [J kg.sup.1 Density C. C. C..sup.1] C..sup.1] [kg m.sup.3] C87800 915 821 27.67 398.86 8,304 CuZnSi alloy** 961 831 43.45 376.80 8,250

[0314] Advantageously, the alloy of the present invention has a lower density than the prior art alloy. Thus, the alloy of the present invention is a lighter weight alloy, but has the similar tensile strength performance, and greater elongation properties than the prior art alloy. Moreover, being a lighter material, the alloy of the present invention, will have less distribution cost, per metre cubed, and from an environmental standpoint, will be more economical to transport per metre. It is particularly desirable that the alloy of the present invention has a true solid state density in the range of from 8.0 kg/m.sup.3 to 8.29 kg/m.sup.3, preferably from 8.0 to 8.28 kg/m.sup.3, suitably from 8.18 to 8.28 kg/m.sup.3. In contrast the alloys of the comparative examples have a true solid state density of 8.30 kg/m.sup.3 or higher.

[0315] A comparison of the performance of CuZnSi of the present invention and C87800 in various fabrication processes is provided in Table 3:

TABLE-US-00006 TABLE 3 Fabrication processes ASTM Temper CuZnSi Code C87800 alloy** Sand mould cast M01 No Yes Die cast M04 Yes Yes Permanent mould cast M05 Yes Yes Continuous cast M07 No Yes Hot forged and air cooled M10 No Yes Hot forged and quenched M11 No Yes

[0316] Advantageously, the alloy of the present invention may be processed in each of the fabrication processes described above, whereas the prior art C87800 alloy is not suitable for sand mould casting, continuous casting, hot forged and air cooled processes, or hot forged and quenched processes.

[0317] The words comprises/comprising and the words having/including when used herein with reference to the present invention are used to specify the presence of stated features, integers, steps or components but do not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0318] It is appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.