stainless steel pipe 420 heat treatment process
Stainless steel pipe 420 heat treatment process
To ensure high strength, high wear resistance and high corrosion resistance, martensitic stainless steel pipe 420 is subjected to have heat treatment which includes softening treatment, quenching and tempering.
By air cooling after forging rolling martensite can be obtained. In order to reduce the hardness, improve its cutting performance, meanwhile in order to eliminate the stress and prevent cracking, the softening treatment should be conducted. Normally have two methods. One is high temperature tempering. The forging is heated to 700-800 ℃, insulation 2- 6 h then air-cooled, the martensite transform to sorbitic, the hardness reduced. After treated the hardness of stainless steel pipe 410 is 170一200 HBS. Stainless steel pipe 420 will be 200-230 HBS. The another one is fully annealed which means heat the forging to 840一900℃, insulation 2-4h, cooling down to 600℃ with the speed greater than or equal to 25℃/h, then air-cooled. The hardness of stainless steel pipe 420 will be reduced to below 170HBS and stainless steel pipe 430 will be reduced to below 217HBS.
Quench of martensitic stainless steel pipe 420: carbides dissolved gradually accompany with the quench temperature rise. Corresponding increases in hardness after quenching. For 3Crl3 & 4Cr13 the temperature should be higher to ensure full dissolution of carbides because of higher carbon content. Normally the heat range is 1000一1050`C. For stainless steel pipe 420 the lower range and for stainless steel pipe 430 high range.
2 Comments so far:Posted by: steve Li on May 31, 2014
Tags: 420 stainless steel