The role of alloying elements in martensitic stainless steel
- 2. The role of Ni in martensitic stainless steel
Ni—— the alloying element has no strengthening effect on the matrix of martensitic stainless steel CA6NM. According to the known Cr will promote the formation of ferrite. Therefore a proper amount of Ni (4~6, wt%) should be added to the 13Cr super martensitic stainless steel CA6NM. Thus will enlarge the γ region and will ensure the formation of martensite structure in the cooling process after solution treatment. Amd that will not producing a single ferrite or other phase.
Alloying element Ni has a positive effect on improving the toughness of steel. When the steel contains some amount of Ni, it will not fully carry out the martensite transformation at room temperature after solid solution treatment. There will be a small amount of residual austenite which is soft. Thus improve the toughness of the martensitic stainless steel CA6NM. Therefore, the appropriate content of Ni is especially important for the mechanical properties of steel.
In addition, Ni can also effectively increase the passivation tendency of Fe-Cr alloy in reduction medium. And also improve the corrosion resistance of steel.