Environmentally-friendly lead-free free-machining zinc white copper and preparation method thereof

Abstract

The invention discloses an environmentally-friendly lead-free free-machining zinc white copper and a preparation method thereof. The zinc white copper comprises the following components in percentage by weight: 27.0-44.0% of zinc, 6.0-25.0% of nickel, 0.05-2.5% of silicon, 0.03-0.1% of cerium, 0.03-1.5% of phosphorus and the balance of copper and inevitable impurity, wherein lead content in the impurity is less than 0.01%. The preparation method comprises the steps of smelting, horizontal continuous casting, cold machining, heat treating and the like. The copper alloy of the invention also has high strength (sigma b=700-750 MPa) and favorable machining performance which is more than 70% of lead brass C36000. Hot extrusion shaping and horizontal continuous casting shaping can be adopted; the zinc white copper has favourable cold and hot pressure processing performance, is an environmentally-friendly novel material, can completely replace lead and zinc white copper to prepare various free-machining elements, can be processed into copper alloy products, such as lines, rods, plates, strips, sections, tubes, cast and the like, can be widely applied to the manufacturing industry, such as pen points, eyeglass accessories, instrument accessories and the like and is an ideal substitute for lead and zinc white copper.

Description

technical field [0001] The invention relates to an environment-friendly lead-free free-cutting zinc-nickel-nickel alloy, in particular to a free-cutting zinc-nickel-nickel alloy with excellent mechanical properties, cutting performance and excellent cold and hot processing performance and a preparation method thereof. Background technique [0002] Lead-zinc cupronickel (such as the German standard Cu43Ni12Zn38Mn5Pb2 alloy) is widely used in the manufacturing industries of nibs, glasses accessories and instrument parts because of its excellent mechanical properties, cutting properties and chemical properties. The amount of lead-zinc cupronickel used in domestic and foreign markets is relatively large . As we all know, lead-containing parts will cause serious environmental pollution and endanger human health during production or use. The United States and the European Union have successively issued relevant laws and regulations to control the lead content in parts. At present...

AI Technical Summary

Problems solved by technology

However, the alloy contains antimony. Due to the large solid-liquid temperature range during the crystallization of zinc white copper, and the poor interdiffusion ability between atoms, the addition of antimony is easy to produce grain boundary segregation, which reduces the grain boundary energy of the copper alloy and makes the grain boundary segregation. The bonding of boundary atoms is weakened, and it is easy to produce a strong tendency of grain boundary embrittlement

Therefore, the addition of antimony element to zinc-nickel-nickel copper requires a high process cost to prevent embrittlement caused by grain boundary segregation, and the raw material price of antimony is higher than that of silicon and other elements, so the overall cost of the alloy is relatively high, and the competitiveness is not high. powerful

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