For Al-Zn alloy, due to the high solubility of Zn in Al, the strength of the alloy can be significantly improved when the mass fraction of Zn is more than 10% in Al. Although this kind of alloy natural aging tendency is large, do not need heat treatment can get high strength, but the disadvantage of this kind of alloy is poor corrosion resistance, high density, easy to produce hot crack when casting. So this kind of alloy is mainly used in manufacturing die casting instrument housing parts. The characteristics and application of common cast Al-Zn alloy are as follows:
(1) ZL401 alloy casting performance is medium, shrinkage cavity and hot crack tendency is small, has good welding performance and cutting performance, high strength as cast, but low plasticity, high density, poor corrosion resistance, ZL401 alloy is mainly used for a variety of pressure casting parts, Automobile and aircraft parts of complex structure and shape with operating temperature not exceeding 200 degrees Celsius.
(2) ZL402 alloy ZL402 alloy casting performance is medium, good fluidity, medium air tightness resistance to hot cracking, good cutting performance, mechanical properties and high impact toughness as cast, but the density is large, the smelting process is complex, Mainly used in agricultural equipment, machine tools, Marine castings, radio devices, oxygen regulators, rotary wheels and air compressor piston, etc.