Nickel is the second most important alloy element in stainless steel after chromium. In order to resist the corrosion of reducing acid and alkali medium, it is not enough to contain only nickel in steel. Nickel must be added to steel. Nickel can promote the stability of stainless steel densification film and improve the thermodynamic stability of stainless steel. Therefore, the coexistence of chromium and nickel in stainless steel can significantly enhance the stainless and corrosion resistance of stainless steel. Nickel is beneficial to high temperature oxidation resistance of stainless steel, but harmful to vulcanization resistance. Because the interaction between nickel and sulfur is easy to form low melting point sulfides. The formation of low melting point sulfides can significantly reduce the hot workability of steel.
The combination of nickel and chromium can significantly improve the corrosion resistance of austenitic stainless steel in caustic medium. Although the PRE value of pitting corrosion resistance and crevice corrosion resistance is not affected by nickel, the effect of nickel is beneficial in general chromium-nickel austenitic stainless steel with low chromium and molybdenum content.
Nickel can significantly improve the plasticity and toughness of stainless steel, and make the brittle temperature of some stainless steel with brittle transition temperature lower.
Nickel can improve the cold formability and weldability of some stainless steels and reduce the tendency of cold working and grinding of austenitic stainless steels.