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Bismuth brass with excellent stress corrosion resistance and preparation method thereof

A stress corrosion-resistant, bismuth-brass technology, applied in the field of copper alloys, can solve the problems of reduced material cutting performance, natural cracking, globe valve cracking, etc., to avoid the risk of later cracking, improve stress corrosion resistance, and improve machinability adverse effects

Active Publication Date: 2021-09-03
JINTIAN COPPER GROUP CORP NINGBO
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

However, the stop valve has entered the service period when it is assembled on the pipeline of the refrigeration equipment. The stress caused by changes, etc., the globe valve is exposed to the atmosphere during its service, and under the action of corrosive media such as trace ammonia and chloride ions in the atmosphere, the globe valve will gradually crack.
[0004] Bi-based free-cutting brass uses Bi element instead of Pb element in lead brass to realize the easy-cutting characteristics of lead-free brass. The existing bismuth brass on the market is mainly Japanese brand C6803, national standard brand HBi59-1, etc., mainly The existing problem is: in the existing Bi-based lead-free brass, the Bi content is high (the Bi content is more than 1.0%). Although the material has excellent cutting performance, due to the high Bi content, Bi is not distributed in the crystal in the form of particles. And on the grain boundary, it is distributed in a thin film. This structural feature aggravates the stress corrosion sensitivity, which makes the brass products with high Bi content prone to natural cracking during service. However, simply reducing the Bi content will reduce the material's corrosion resistance. cutting performance

Method used

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  • Bismuth brass with excellent stress corrosion resistance and preparation method thereof
  • Bismuth brass with excellent stress corrosion resistance and preparation method thereof
  • Bismuth brass with excellent stress corrosion resistance and preparation method thereof

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0033] 1) Smelting: According to the chemical composition of the alloy, the ingredients are prepared, and cathode copper, Sn ingot, zinc ingot, Bi ingot, Ni plate, 50% copper Fe master alloy, 20% copper Si master alloy, 17% copper P master alloy are added to the process. Melt in a frequency induction furnace. After all the raw materials are melted, add a slag cleaning agent to stir to remove the slag, adjust the composition, raise the temperature to 1020-1045°C, let it stand for 5 minutes after spraying fire, then transfer to the holding furnace, add charcoal to cover, and the covering thickness is 70 ~80mm.

[0034] 2) Horizontal continuous casting: When the temperature of the holding furnace reaches the casting temperature of 1020-1030°C, the casting ingot is pulled horizontally. The diameter of the casting ingot is 245mm, and the sawing length is 800mm.

[0035]3) Extrusion: Extrude straight bars on a 3150-ton ingot reverse extrusion machine, extrusion temperature: 670°C, e...

Embodiment 2

[0041] 1) Smelting: According to the chemical composition of the alloy, the ingredients are prepared, and cathode copper, Sn ingot, zinc ingot, Bi ingot, Ni plate, 50% copper Fe master alloy, 20% copper Si master alloy, 17% copper P master alloy are added to the process. Melt in a frequency induction furnace. After all the raw materials are melted, add a slag cleaning agent to stir to remove the slag, adjust the composition, raise the temperature to 1020-1045°C, let it stand for 5 minutes after spraying fire, then transfer to the holding furnace, add charcoal to cover, and the covering thickness is 70 ~80mm.

[0042] 2) Horizontal continuous casting: When the temperature of the holding furnace reaches the casting temperature of 1020-1030°C, the casting ingot is pulled horizontally. The diameter of the casting ingot is 245mm, and the sawing length is 800mm.

[0043] 3) Extrusion: Extrude straight bars on a 3150-ton ingot reverse extrusion machine, extrusion temperature: 700°C, ...

Embodiment 3

[0049] 1) Smelting: According to the chemical composition of the alloy, the ingredients are prepared, and cathode copper, Sn ingot, zinc ingot, Bi ingot, Ni plate, 50% copper Fe master alloy, 20% copper Si master alloy, 17% copper P master alloy are added to the process. Melt in a frequency induction furnace. After all the raw materials are melted, add a slag cleaning agent to stir to remove the slag, adjust the composition, raise the temperature to 1020-1045°C, let it stand for 5 minutes after spraying fire, then transfer to the holding furnace, add charcoal to cover, and the covering thickness is 70 ~80mm.

[0050] 2) Horizontal continuous casting: When the temperature of the holding furnace reaches the casting temperature of 1020-1030°C, the casting ingot is pulled horizontally. The diameter of the casting ingot is 245mm, and the sawing length is 800mm.

[0051] 3) Extrusion: Extrude straight bars on a 3150-ton ingot reverse extrusion machine, extrusion temperature: 690°C, ...

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Abstract

The invention discloses bismuth brass with excellent stress corrosion resistance. The bismuth brass is characterized in that the bismuth brass comprises, by mass percent, 58wt%-60wt% of Cu, 0.5wt%-1.5wt% of Sn, 0.5wt%-1.0wt% of Bi, 0.1wt%-0.5wt% of Si, 0.2wt%-0.8wt% of Ni, 0.02wt%-0.15wt% of P, not larger than 0.01wt% of Pb and the balance Zn and inevitable impurities. According to the bismuth brass, the low-content Bi is added, through combination with adding of Sn, Si, Ni and P, the cutability adverse effect brought by the low-content Bi is reduced, the risk of later cracking is reduced, the stress corrosion resistance of the bismuth brass is improved, and the bismuth brass can be used for machining stop valves used on refrigeration equipment.

Description

technical field [0001] The invention belongs to the technical field of copper alloys, in particular to bismuth brass with excellent stress corrosion resistance and a preparation method thereof. Background technique [0002] Traditional lead brass has good mechanical properties and physical properties, as well as good cold and hot processing properties and cutting properties, and is cheap, so it is widely used in instrumentation, electronics, electrical appliances, daily hardware, drinking water systems and other fields, especially HPb59-1 is used the most. However, the lead contained in drinking water system pipe fittings and other waste electronics and electrical appliances can easily enter the water or soil, and the human body will endanger health after ingestion. Therefore, the United States, Japan, and the European Union have all put forward corresponding restrictions on the lead content of these products. EU RoHS2.0 "Instructions on Restricting the Use of Certain Haza...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C22C9/04C22F1/08
CPCC22C9/04C22F1/08
Inventor 叶东皇郑恩奇傅杰巢国辉
Owner JINTIAN COPPER GROUP CORP NINGBO