The hard nickel casting will contain its nickel and chromium alloy elements in the process of production. The addition of nickel can effectively improve its hardenability during operation. In this way, the metal matrix with martensite as the main body can be obtained.The addition of chromium prevents the precipitation of graphite and produces high - hardness carbide.
The heat treatment process for hard nickel casting
Nickel hard casting can be heated to 275 ℃ when made, insulation 12 ~ 24 h, and then air cooling, thus as-cast organization of retained austenite into bainite or martensite, the as-cast martensite have been tempered in the organization, and thus improve the hardness and impact fatigue life of nickel and iron.
Heated to 450 ℃, nickel hard casting insulation 4 h, then USES the air cooling or furnace cooling to room temperature, also can use double heat treatment process in operation, the nickel iron heating to 450%, thermal insulation, 4 h, and then to 275 ℃ cold insulation 4 ~ 16 h air cooling.This double heat treatment process can reduce the carbon content of retained austenite in the structure of nickel hard iron and make it change into martensite in the subsequent cooling process.In the 275 ℃ heat preservation purpose is to make the new get tempered martensite, at the same time make the austenite into martensite.The impact fatigue life of hard nickel iron is higher than that of simple heat treatment.http://www.wuxiorient.com/