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Copper-based alloy excellent in dezincing resistance

A copper-based alloy and dezincification-resistant technology, applied in the field of copper-based alloys, can solve the problems of poor hot workability, hindering waste sorting and circulation, and difficult to deal with forged products.

Inactive Publication Date: 2004-08-18
DOWA METALTECH CO LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, since Pb-free brass uses Pb-free raw materials and Bi master alloys or Cu-Si master alloys, etc., there is a problem that the price of raw materials has to be high, and there is also a problem that the separation and distribution of waste materials are hindered by the division into two systems.
[0007] In addition, if the lead-free easy-cutting brass of JP-A-2002-3967 does not break the β phase which is poor in dezincification resistance, it is difficult to obtain the dezincification resistance effect. Therefore, the area of ​​the β phase becomes smaller at high temperature, so There is a problem of poor hot workability. In addition, since the dezincification resistance characteristics fluctuate due to the precipitation form and area ratio of the α phase and β phase, heat treatment is required after hot working or wire drawing, and it is difficult to correspond to forging. Products and other heat-processed products without heat treatment

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0036] Table 1 shows the chemical composition (% by weight) of the alloys to be tested. Regardless of which alloys are melted in an induction furnace, they are semi-continuously cast into blanks with a diameter of 80 mm from the liquidus temperature of +100°C, and each blank is kept at 800°C for 30 minutes. Under hot extrusion until the diameter is 30mm, then air cooling. At this stage, necessary test pieces for measurement are collected. In forging, the aforementioned hot extrusion material is forged at a billet temperature of 650-750°C, an upset rate of 30-70%, and a deformation speed of 15mm / sec, and then at a speed of 0.32-5.4°C / sec. cool down.

[0037] For each example, machinability, tensile strength, elongation, hardness, dezincification resistance, hot forgeability, and eluted lead were evaluated together with castability. The results are shown in Tables 2 to 5. Each measurement method is as follows.

[0038] Castability: The depth of surface defects such as surfa...

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Abstract

A copper-based alloy excellent in dezincing resistance comprises, in percentage by weight, Cu: 57-69%, Sn: 0.3-3%, Si: 0.02-1.5%, Bi: 0.5-3%, and Pb: not more than 0.2%, where the ratio of Si / Sn expressed in weight percentage is in the range of 0.05-1 and apparent zinc content as defined by the following formula is in the range of more than 39-50 wt. %, and the balance of unavoidable impurities: Apparent Zn content=[(Zn %+2.0xSn %+10.0xSi %) / (Cu %+Zn %+2.0xSn %+10.0xSi %)]x100. Despite the fact that contains no added environment-unfriendly Pb, the alloy exhibits enhanced cuttability, together with excellent forgeability, dezincing resistance and hot forgeability.

Description

technical field [0001] The present invention relates to a copper-based alloy that does not contain environmentally unfavorable Pb, has excellent corrosion resistance against dezincification corrosion even when used in the presence of a corrosive aqueous solution, and is excellent in hot workability and machinability. Background technique [0002] Among copper-based alloys, brass materials called Cu-Zn-based alloys have been widely used for waterway parts and gas valves since ancient times because they are excellent in hot workability and machinability. Among these, brass rods for forging (JIS C 3771), free-cutting brass rods (JISC 3604), high-strength brass rods (JIS C 6782) and the like are known, but these copper-based alloys, no matter which one All have the characteristics of high lead content which is harmful to the environment. [0003] In addition, these alloys are characterized by very poor dezincification resistance because Zn in the β phase has a strong ionization...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C1/02C22C9/00C22C9/02C22C9/04C22F1/08
CPCC22C9/04C22F1/08
Inventor 山岸义统
Owner DOWA METALTECH CO LTD
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