Si in CA6NM martensitic stainless steel

Si is a strong ferrite stabilizing element in martensitic stainless steel. Si can suppress temper embrittlement and the decomposition of retained austenite during tempering. At high temperature or in a strong oxidizing medium adding a certain amount of Si to the surface to form a layer of Si02 oxide layer. As a result, it improves the oxidation resistance or corrosion resistance of steel. At the same time adding Si may inhibit the pitting corrosion of stainless steel in Cl. But, if the content of Si exceeds 4% there will improve the brittleness of steels.