How to Get Martensite in the Processing of Stainless Steel
The purpose of the solution treatment is to obtain some martensite to increase the hardness of stainless steel. Let's take a look at the solution treatment of stainless steel pipes:
1. Intermediate statute of limitations. Keeping the temperature(760±15) ℃ for 90min after the solution treatment, so that Cr23C6 carbides are precipitated from the austenite, which reduces the content of carbon and alloying elements in the austenitic 904L stainless steel pipe, and increases the Ms point. After reaching 70°C and then cooling to room temperature, martensite + α ferrite + retained austenite will be obtained, and the retained austenite will be decomposed after aging at 510°C.
2. After high temperature adjustment and cryogenic treatment, heat stainless steel to 950℃ for 90min. Due to the increase of the Ms point, a small amount of martensite can be obtained by cooling to room temperature, and get more martensite after cold treatment at -70℃ for 8h.
3. After solution treatment by cold deformation method, cold deformation at room temperature. The amount of martensite formed in the 904L seamless pipe during cold deformation is related to the amount of deformation and the composition of the 904L stainless steel pipe.