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Patent
San Etsu Metals Co. | Date: 2015-08-28

A copper-base alloy includes 63.5 to 69.0 mass % of Cu, 1.2 to 2.0 mass % of Sn, 0.15 mass % or less of Fe, 0.1 to 2.0 mass % of Pb, 0.01 to 0.2 mass % of Al, 0.06 to 0.15 mass % of Sb, and 0.04 to 0.15 mass % of P when the copper-base alloy includes 63.5 mass % or more and less than 65.0 mass % of Cu, or 0.15 mass % or less of P when the copper-base alloy includes 65.0 to 69.0 mass % of Cu, with the balance being Zn and unavoidable impurities.


Patent
San Etsu Metals Co. | Date: 2010-04-16

A high-strength copper alloy contains 20 to 45% of zinc, 0.3 to 1.5% of iron, 0.3 to 1.5% of chromium, and a balance of copper, based on mass.


Imai H.,Osaka University | Shufeng L.,Osaka University | Atsumi H.,Osaka University | Kosaka Y.,SAN ETSU METALS Co. | And 2 more authors.
Materials Transactions | Year: 2010

The aim of this paper was to produce a lead-free machinable brass dispersed with bismuth and graphite particles by powder metallurgy process. The effect of the machinable elements on the elongation and machinability of extruded materials was investigated. The Cu-40 mass%Zn (Cu-40Zn) brass powder with 0-3.23 mass% bismuth additions were produced by rapid solidification process, having a mean particle size of 150 μm. It was found that bismuth were uniformly dispersed as the island of about 5 μm in the brass powder matrix, and appeared at the brass powder surface after heat treatment over the melting point of bismuth. When 2.2 mass% or more bismuth was added, the quantity of bismuth appearing at the brass powder surface increased because of saturated quantity of bismuth elements in the brass powder. There were bismuth islands of tens of microns in the extruded brass with 2.2 mass% or more bismuth addition. These bismuth islands were depressed the elongation of extruded materials. The graphite particles with mean particle size of 5 μm were also used as raw powder. 0-0.5 mass% graphite particles were mixed with the as- atomized brass powder by dry process. The elongation of the extruded brass alloy with both bismuth and graphite particles additions increased comparing with that of extruded brass with bismuth addition. The extruded brass using the as-atomized brass powder with 2.2 mass% bismuth and 0.5 mass% graphite particles indicated excellent machinability as well as the conventional leaded brass. Synergy effect of bismuth and graphite particles on the improvement of elongation and machinability of brass alloys was much useful compared with the brass containing only bismuth or graphite particles. ©2010 The Japan Institute of Metals. Source


Atsumi H.,Osaka University | Imai H.,Osaka University | Li S.,Osaka University | Kondoh K.,Osaka University | And 2 more authors.
Materials Science and Engineering A | Year: 2011

High-strength, lead-free machinable α-β duplex phase brass (Cu-40Zn) with 0.3mass% chromium, 0.2mass% iron, 0.6mass% tin, and 1-3mass% bismuth (Cu-40Zn-Cr-Fe-Sn-Bi) were prepared using a casting process, and their microstructures, mechanical properties, and machinability were investigated. Cast Cu-40Zn-Cr-Fe-Sn-Bi exhibited α-β duplex phase structures dispersed with Cr-Fe intermetallic compounds (IMCs) and spherical Bi particles that existed in the β-phase. The Bi particle size in this phase was smaller than that of irregularly shaped Bi particles in or around the α-phase; thus, cast specimens with large area fractions of the β-phase had more finely dispersed Bi particles. Furthermore, the additional Bi did not react with the added solid solution strengthening elements of Cr, Fe, and Sn. Conversely, the extruded Cu-40Zn-Cr-Fe-Sn-Bi consisted of fine, uniform α-β duplex phases dispersed with fine, discrete Cr-Fe IMCs, and the Bi particles were also slightly elongated along the extrusion direction. Analysis of back-scattered SEM images determined that the number of Bi particles in the wrought alloy matrix was 1500-3000/mm2 in the transverse cross-section of the extrusion direction. The average yield strength (YS) and average ultimate tensile strength (UTS) of the extruded Cu-40Zn-Cr-Fe-Sn-Bi alloy were 288MPa and 601MPa, respectively. Based on the similar tensile properties of this alloy to those of Cu-40Zn-Cr-Fe-Sn, the main strengthening mechanism in the former alloy was due to solid solution strengthening with elemental additives and the increased area present as the hard β-phase. Furthermore, this extruded alloy exhibited an increase of 29% YS and 40% UTS compared to traditional machinable brass Cu-40Zn with 3.2mass% lead (Cu-40Zn-Pb). The machinability of the extruded Cu-40Zn-Cr-Fe-Sn-Bi was also 25% lower than that of the Cu-40Zn-Pb alloy. © 2011 Elsevier B.V. Source


Li S.,Osaka University | Imai H.,Osaka University | Kondoh K.,Osaka University | Kojima A.,SAN ETSU METALS Co. | And 3 more authors.
Materials Chemistry and Physics | Year: 2012

Effect of Ti and Sn alloying elements on microstructure and mechanical properties of 60/40 brass has been studied via the powder metallurgy (P/M) route. The water-atomized BS40-0.6Sn1.0Ti (Cu40wt%Zn-0.6wt%Sn1.0wt%Ti) pre-alloyed powder was consolidated at various temperatures within range of 400-600°C using spark plasma sintering (SPS) and hot extrusion was carried out at 500°C. Effects of extrusion temperature on microstructure and tensile strength were investigated by employing SEM-EDS/EBSD, TEM, XRD and tensile test. Results indicated that super-saturated solid solution Ti and Sn elements created high chemical potential for a precipitate reaction in rapidly solidified brass powder, which showed significant strengthening effects on the extruded sample consolidated at lower temperature. Solid solubility of Ti in brass matrix decreased with increasing of sintering temperature, thus resulted in degradation of mechanical properties. Consequently, lower hot processing temperature is necessary to obtain excellent mechanical properties for BS40-0.6Sn1.0Ti during sintering and extrusion. An yield strength of 398 MPa and ultimate tensile strength of 615 MPa were achieved, they respectively showed 31.3% and 22.9% higher values than those of extruded Cu40Zn brass. © 2012 Elsevier B.V. All rights reserved. Source

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