Lead-free free-cutting magnesium brass alloy and its manufacturing method

a free-cutting, magnesium brass technology, applied in the field of magnesium brass alloys, can solve the problems of unavoidable pb contamination of drinking water, more harmful to the human body and the environment, and the contamination of the drinking water by pb

US20090311127A1Inactive Publication Date: 2009-12-17XU CHUANKAI +2
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Patent Information

Authority / Receiving Office
US · United States
Current Assignee / Owner
Publication Date
2009-12-17
Estimated Expiration
Not applicable · inactive patent

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Abstract

A lead-free free-cutting magnesium brass alloy comprises 56.0 to 64.0 wt % Cu, 0.6 to 2.5 wt % Mg, 0.15 to 0.4 wt % P and other elements 0.002 to 0.9 wt % which comprise at least two elements selected from the group consisting of Al, Si, Sb, Sn, Re, Ti and B and the balance being Zn and unavoidable impurities. The process for producing such alloy is also proposed. The invented alloy is excellent in cuttability, castability, hot and cold workability, corrosion resistance, mechanical properties and weldability and particularly applicable in spare parts, forging and castings which need cutting, grinding and electroplating process. The cost of necessary metal materials of the invented alloy is lower than lead-free free-cutting bismuth and antimony brass alloy and is equivalent to lead-contained brass alloy.
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Description

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation of U.S. patent application Ser. No. 12 / 207,136 filed on Sep. 9, 2008, which claims priority from Chinese Patent Application No. 200810110818.3 filed Jun. 11, 2008.FIELD OF THE INVENTION

[0002] The present invention generally relates to a magnesium brass alloy, especially a lead-free free-cutting magnesium brass alloy which is applicable in spare parts for a water supply system.BACKGROUND OF THE INVENTION

[0003] It is well-known that lead-containing brass alloys such as CuZn40Pb1, C36000, C3604 and C3771 usually contain 1.0-3.7 wt % Pb for ensuring excellent free-cuttability.

[0004] Lead-containing brass alloys are still widely used in the manufacture of many products due to their excellent cuttability and low cost. However, Pb-contaminated steam produced by the process of smelting and casting lead-contained brass alloy and Pb-contaminated dust produced in the process of cutting and grinding the lead-contained ...

Examples

examples

[0030]The alloy composition in examples is shown in Table 1. Some alloy ingot is extruded at the temperature ranging from 580° C. to 700° C. with an elongation coefficient of greater than 30 into bar materials. Some alloy ingot is forged at the temperature ranging from 590° C. to 710° C. to be spare parts with a complex structure for a water supply system. Some alloy ingot is remelted at the temperature among 990 to 1015° C. to make faucets by low pressure die casting.

TABLE 1Composition of lead-free free-cutting magnesium brass alloy (wt %)ExamplesCuMgPSbSiAlSnTiBReZn159.250.580.290.210.380.200.040.0004—Balance259.200.610.260.400.210.250.030.0003—Balance358.630.700.280.250.360.170.200.0030.00030.005Balance459.800.890.200.160.330.150.030.0003—Balance559.760.940.150.110.350.100.020.0002—Balance658.890.970.180.310.200.020.0002—Balance760.211.350.150.120.200.170.010.0001—Balance860.401.600.190.140.230.150.010.0001—Balance960.402.110.150.160.100.220.010.0001—Balance

[0031]The lead-free br...