- The role of alloying elements in martensitic stainless steel CA6NM: Cr
- 1. The role of alloy element in martensitic stainless steel CA6NM: Cr
- Cr——one of major alloying elements in martensitic stainless steel CA6NM. It plays a decisive role in corrosion resistance. With Cr in the steell the corrosion resistance of stainless steel in the corrosive medium will increase accordingly. Cr can effectively reduce the sensitivity of steel to pitting corrosion. There will improve pitting corrosion resistance when steels contain Mo at the same time. Also Cr is a strong ferrite formation element. It can greatly reduce the austenite phase in the phase diagram. The content of Cr in martensitic stainless steel is generally between 10.5~18%.
Cr is a typical ferrite formation element. Excessive Cr can promote δ ferrite formation. Therefore after solution treatment it will not get full martensite. There is part of delta ferrite. Thereby it’ll affect the steel toughness and stress corrosion resistance. Therefore, the Cr content of super martensitic stainless steel should be strictly controlled between 12% and 13%.