High tensile brass alloy and high tensile brass alloy product

Abstract

The present disclosure relates to a high-tensile brass alloy containing 55-65 wt-% copper; 1-2.5 wt-% manganese; 0.7-2 wt % tin; 0.2-1.5 wt % iron; 2-4 wt % nitrogen; 2-5 wt % aluminum; 0.2-2 wt % silicon; 2.0 wt % cobalt maximum; and the remainder zinc together with unavoidable impurities, wherein the sum of the elements manganese and tin is at least 1.7 wt % and at most 4.5 wt.

Claims

1. A high-tensile brass alloy comprising 55-65 wt % Cu; 1-2.5 wt % Mn; 0.7-2 wt % Sn; 0.2-1.5 wt % Fe; 2-4 wt % Ni; 2-5 wt % Al; 0.2-2 wt % Si; 2.0 wt % Co maximum; 0.1 wt % Pb maximum; and the remainder Zn together with unavoidable impurities; wherein the sum of the elements Mn and Sn is at least 1.7 wt % and is at most 4.5 wt %.

2. The high-tensile brass alloy of claim 1, wherein the elements Mn and Sn are present in the alloy in a Mn to Sn ratio between 1.25 and 0.85.

3. The high-tensile brass alloy of claim 2, wherein the ratio of the elements Mn to Sn is between 1.1 and 0.92.

4. The high-tensile brass alloy of claim 3, comprising 59-65 wt % Cu; 1.3-1.65 wt % Mn; 1.3-1.65 wt % Sn; 0.5-1.0 wt % Fe; 2.4-3.4 wt % Ni; 3.1-4.1 wt % Al; 1.0-1.7 wt % Si; 2.0 wt % Co maximum; 0.1 wt % Pb maximum; and the remainder Zn together with unavoidable impurities.

5. The high-tensile brass alloy of claim 1, comprising 59-65 wt % Cu; 1.3-1.65 wt % Mn; 1.3-1.65 wt % Sn; 0.5-1.0 wt % Fe; 2.4-3.4 wt % Ni; 3.1-4.1 wt % Al; 1.0-1.7 wt % Si; 2.0 wt % Co maximum; 0.1 wt % Pb maximum; and the remainder Zn together with unavoidable impurities.

6. The high-tensile brass alloy of claim 5, wherein the Cu content is 59-62 wt %.

7. The high-tensile brass alloy of claim 5, wherein the Co content is 0.9-1.6 wt %, in particular 0.9-1.5 wt %, particularly preferably 0.9-1.1 wt %.

8. A high-tensile brass alloy product manufactured from the high-tensile brass alloy of claim 5, wherein the high-tensile brass alloy product is made up predominantly of the phase.

9. The high-tensile brass alloy product of claim 8, wherein the Cu content is 59-62 wt % and the proportion of the phase is less than 10%.

10. The high-tensile brass alloy product of claim 8, wherein the proportion of the phase is less than 35%.

11. The high-tensile brass alloy product of claim 10, wherein the Co content is 0.9-1.6 wt %.

12. The high-tensile brass alloy product of claim 8, wherein the alloy product is a bearing part, preferably for use in a bearing in an oil environment possibly having acidic conditions.

13. The high-tensile brass alloy product of claim 12, wherein the bearing part is a part for a turbocharger bearing.

14. The high-tensile brass alloy product of claim 8, wherein the proportion of intermetallic phases is between 5 and 9%.

15. A high-tensile brass alloy product manufactured from the high-tensile brass alloy of claim 1, wherein the high-tensile brass alloy product is made up predominantly of the phase.

16. The high-tensile brass alloy product of claim 15, wherein the proportion of intermetallic phases is between 5 and 9%.

17. The high-tensile brass alloy product of claim 15, wherein the electrical conductivity of the high-tensile brass alloy product is <10 MS/m.

18. The high-tensile brass alloy product of claim 17, wherein the electrical conductivity of the high-tensile brass alloy product is <8.2 MS/m.

19. The high-tensile brass alloy product of claim 15, wherein the alloy product is a bearing part, preferably for use in a bearing in an oil environment possibly having acidic conditions.

20. The high-tensile brass alloy product of claim 19, wherein the bearing part is a part for a turbocharger bearing.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The present disclosure is explained below based on specific exemplary embodiments, with reference to the figures, which show the following:

(2) FIG. 1: shows a light micrograph of the surface of a first test specimen of a first alloy,

(3) FIG. 2: shows light micrographs of samples of the same alloy as the test specimen in FIG. 1, but extruded,

(4) FIG. 3: shows four scanning electron micrographs of the extruded sample in FIG. 2,

(5) FIG. 4: shows the scanning electron micrographs of images 1, 2, and 4 in FIG. 3 with identification of the areas in which EDX analyses were carried out,

(6) FIG. 5: shows a hardening diagram of the sample of the first alloy,

(7) Table 1: shows the EDX analyses of the sample points in FIG. 4,

(8) FIG. 6: shows a micrograph of a sample of the alloy from the preceding figures after carrying out a corrosion test,

(9) FIG. 7: shows micrographs of samples, made of a first comparative alloy, that were subjected to the same corrosion test,

(10) FIG. 8: shows micrographs of samples, made of a second comparative alloy, that were subjected to the same corrosion test,

(11) FIG. 9: shows a light micrograph of the surface of a sample of a second alloy,

(12) FIG. 10: shows light micrographs of samples of the same alloy, but extruded,

(13) FIG. 11: shows four scanning electron micrographs of the extruded sample in FIG. 10,

(14) FIG. 12: shows scanning electron micrographs of the samples in FIG. 11 with identification of the areas in which EDX analyses were carried out,

(15) FIG. 13: shows a hardening diagram of the sample of the second alloy,

(16) FIG. 14: shows micrographs of a sample of the second alloy after carrying out a corrosion test, and

(17) Table 2: shows the EDX analyses of the sample points in FIG. 12.

(18) Before further explaining the depicted embodiments, it is to be understood that the present disclosure is not limited in its application to the details of the particular arrangements shown, since the present disclosure is capable of other embodiments. It is intended that the embodiments and figures disclosed herein are to be considered illustrative rather than limiting. Also, the terminology used herein is for the purposes of description and not limitation.

DETAILED DESCRIPTION

(19) Test 1:

(20) In a first test series, test specimens of an alloy having the following composition were poured and extruded:

(21) TABLE-US-00001 Cu Mn Sn Fe Ni Al Si Zn Sample 1 60.7 1.5 1.5 0.8 3.0 3.8 1.4 Remainder

(22) The light micrograph of the casting sample depicted in FIG. 1 shows the predominance of the phase over the phase. Silicides are discernible. The grain size of the phase is several times larger than that of the phase, which may be indicated with an average grain size of approximately 7-10 m.

(23) The same image, also for the extruded samples of the same alloy, shows that the silicides are stretched as a result of the pressing operation due to the extrusion process at the end of pressing (see right portion of FIG. 2).

(24) The proportion of the intermetallic phases is approximately 6% in both samples. The mixed crystal proportion is 6% maximum. The remainder is determined by the mixed crystal proportion.

(25) The small size of the deposits of much less than 1 m is apparent in the scanning electron micrographs of the extruded sample depicted in FIG. 3.

(26) EDX analyses were performed on images 1, 2, and 4 of the scanning electron micrographs in FIG. 3. The areas in which the EDX analyses were conducted are identified in FIG. 4 and provided in Table 1.

(27) As a result, it can be established that manganese is bound predominantly in the silicides, while tin is dissolved in the phase. Certain quantities of manganese are also dissolved in the phase. This is particularly advantageous because not only is a cover layer-forming agent present, an cover layer-forming agent (containing manganese) is present as well, due to the dissolved tin in the phase.

(28) Hardness tests were conducted on the extruded sample with respect to microhardness and macrohardness. The macrohardness was measured according to Brinell, with a result of 266 HB 2.5/62.5. The microhardness was determined according to Vickers. A Vickers hardness of 254-270 HV 0.01 was determined in the matrix. The intermetallic phases are naturally much harder. Hardness's between 768 and 1047 HV 0.01 were determined here.

(29) FIG. 5 shows the hardening behavior during annealing of the sample made from this alloy. It is apparent that a hardness maximum is present between 250 and 300 C. In addition, these samples showed no, or only negligible, softening at elevated temperatures.

(30) This sample was subsequently tested for various strength parameters. The following results were obtained:

(31) TABLE-US-00002 Rp0.2 Rm A [N/mm.sup.2] [N/mm.sup.2] [%] Hardness 670 840 3.7% 266 HB 2.5/62.5

(32) These results were verifiable with further test specimens. The following strength values were obtained for an extruded and annealed sample having the same composition as that previously described:

(33) TABLE-US-00003 Rp0.2 Rm A [N/mm.sup.2] [N/mm.sup.2] [%] Hardness 592 727 3.5% 261 HB 2.5/62.5

(34) These samples showed a very fine structure and high strength and hardness overall.

(35) The first-mentioned sample together with reference samples was subjected to corrosion testing.

(36) For purposes of the corrosion testing, the samples were halfway immersed in a mixture of motor oil, 20% bioethanol E85 (85% ethanol), and sulfuric acid. The pH was adjusted to 2.6. The tests were carried out at 60 C. The sample was kept in this mixture for two days, then removed and evaluated by light microscopy.

(37) FIG. 6 shows the portion of the sample subjected to corrosion testing. The light micrograph in FIG. 6 shows that there is only a slight corrosion attack, and therefore deeper areas of material remain effectively protected from corrosion. The formation of a cover layer that protects the deeper areas from corrosion was observed in this sample. The cover layer is marked with respect to its thickness in the figure. The measurement was performed in a slight surface indentation. The cover layer is indicated by a dashed line in FIG. 6 for better identification. As shown by the tests, this cover layer has good adherence. It is emphasized that not only the phase, but also the grain boundaries and the phase are corrosion-resistant.

(38) FIG. 7 shows the result for a comparative sample made of the alloy CuZn37Mn3Al2PbSi, which was produced and tested for corrosion using the same parameters. Localized layer formation is clearly apparent, in the image on the left.

(39) A reference sample made of the alloy CuZn36 was also produced and tested for corrosion using the same parameters. Formation of corrosion cracks and development of plugs were observed in this sample.

(40) The image on the right in the bottom row was additionally treated in pure, highly concentrated sulfuric acid.

(41) The electrical conductivity of this sample was 7.8 MS/m, and therefore is at the same level as the electrical conductivity of the comparative alloy CuZn37Mn3Al2PbSi. It is thus shown that the electrical conductivity did not increase, or in any case did not increase appreciably, compared to the reference sample because of the corrosion-increasing measures. The electrical conductivity of the other reference alloy was 15.5 MS/m.

(42) Test 2:

(43) In a second test series, test specimens of an alloy having the following composition were poured and extruded:

(44) TABLE-US-00004 Cu Mn Sn Fe Ni Al Si Co Zn Sample 1 61.2 1.5 1.5 0.8 3.0 3.8 1.4 1.2 Remainder

(45) The light micrograph of the casting sample depicted in FIG. 9 shows the predominance of the phase over the phase. Silicides having grain sizes of approximately 5-7 m are discernible. Compared to the alloy in Test 1, the grains of the phase in this alloy are much larger than those of the phase.

(46) The same image, also for the extruded samples of the same alloy, shows that the silicides are stretched as a result of the pressing operation due to the extrusion process at the end of pressing (see right portion of FIG. 10).

(47) The proportion of the intermetallic phases is approximately 7% in the samples. The mixed crystal proportion is 30% maximum. The remainder is determined by the mixed crystal proportion. The alloy is particularly well suited for cold finishing due its high a proportion.

(48) The small size of the deposits is apparent in the scanning electron micrographs of the extruded sample depicted in FIG. 11.

(49) FIG. 12 shows scanning electron micrographs in areas of the samples in FIG. 11. The areas in which the EDX analyses were conducted are identified in FIG. 12 and provided in Table 2.

(50) As a result, it can be established that manganese is bound predominantly in the silicides, while tin is dissolved in the phase. Certain quantities of manganese are also dissolved in the phase. This is particularly advantageous because not only is a cover layer-forming agent present, an cover layer-forming agent (containing manganese) is present as well, due to the tin that is dissolved in the phase.

(51) Hardness tests were conducted on the extruded sample with respect to microhardness and macrohardness. The macrohardness was measured according to Brinell, with a result of 204-225 2.5/62.5. The microhardness was determined according to Vickers. A Vickers hardness of 129-172 HV 0.01 was determined in the matrix, and 240-305 HV 0.01 in the phase. The intermetallic phases are naturally much harder. Hardness's between 826 and 961 HV 0.01 were determined here.

(52) FIG. 13 shows the hardening behavior during annealing of the sample made from this alloy. It is apparent that a hardness maximum is present at approximately 300 C. Marked softening was determinable above 450 C. During annealing above 600 C., an increase in hardness was observed due to conversion of the phase portions to phase portions.

(53) This sample was subsequently tested for various strength parameters. The following results were obtained:

(54) TABLE-US-00005 Rp0.2 Rm A [N/mm.sup.2] [N/mm.sup.2] [%] Hardness 455 680 4.7 44HB 2.5/62.5

(55) These samples showed a very fine structure and high strength and hardness overall.

(56) The sample together with reference samples was subjected to corrosion testing. The corrosion tests were carried out as previously described. The same reference samples were used as in Test 1. In this regard, reference is made to FIGS. 7 and 8 and the accompanying discussion.

(57) FIG. 14 shows two light micrographs of the sample of the second alloy after the corrosion treatment. Formation of a cover layer was observed. Thus, deeper areas of material remain effectively protected from corrosion. In addition to the phase, also the grain boundaries and the phase are corrosion-resistant for this sample.

(58) The electrical conductivity of this sample was 6.8 MS/m and is thus even lower than the electrical conductivity of the reference alloy CuZn37Mn3Al2PbSi.

(59) Based on a comparison of the results obtained with the alloy of Test 1 to those of the alloy of Test 2, it is apparent that the alloy according to Test 1, which contains no cobalt, tends toward much stronger deposit hardening and deposit solidification. In the alloy according to Test 2, which contains cobalt, this element favors the formation of fairly coarse primary grains as secondary deposits of the silicides. The results show that cobalt influences the kinetics of the silicide formation. If a higher level of silicide involvement is desired, the alloy is designed without cobalt, or with only a small proportion of cobalt. The differences in the formation of the phase are likewise attributable to the incorporation of cobalt. Cobalt has a stabilizing effect on the phase.

(60) The present disclosure was described based on exemplary embodiments. A person skilled in the art will derive numerous embodiments for implementing the present disclosure without departing from the scope of the present claims. While a number of aspects and embodiments have been discussed above, those of skill in the art will recognize certain modifications, permutations, additions and sub-combinations therefore. It is therefore intended that the following appended claims hereinafter introduced are interpreted to include all such modifications, permutations, additions and sub-combinations, which are within their true spirit and scope. Each embodiment described herein has numerous equivalents.

(61) The terms and expressions which have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the present disclosure claimed. Thus, it should be understood that although the present disclosure has been specifically disclosed by preferred embodiments and optional features, modification and variation of the concepts herein disclosed may be resorted to by those skilled in the art, and that such modifications and variations are considered to be within the scope of this present disclosure as defined by the appended claims. Whenever a range is given in the specification, all intermediate ranges and subranges, as well as all individual values included in the ranges given are intended to be included in the disclosure. When a Markush group or other grouping is used herein, all individual members of the group and all combinations and sub-combinations possible of the group are intended to be individually included in the disclosure.

(62) In general, the terms and phrases used herein have their art-recognized meaning, which can be found by reference to standard texts, journal references and contexts known to those skilled in the art. The above definitions are provided to clarify their specific use in the context of the present disclosure.