Chromium (Cr): For heat-resistant stainless steel, Cr can maintain its own stability at high temperatures, and will not oxidize and fall off. However, the content of Cr should not be too high. If it is too high, the toughness of the stainless steel itself will also decrease, because Cr is a component that can promote the appearance of α, while suppressing γ, too much α will easily lead to the production of some brittle phases in the material. Therefore, in austenitic stainless steel, we hope that the Cr content will remain moderate, which can not only ensure the properties of the material, but also prevent the appearance of some brittle phases.
Nickel (Ni): Ni is a very important element in heat-resistant austenitic stainless steel, and it plays a very active role in promoting the formation of γ. In the phase diagram, the increase of the Ni element content can lower the transition temperature of γ to α, which can enhance the stability of the austenite of the matrix structure. In addition, proper adjustment of the Ni content in stainless steel can significantly improve the comprehensive mechanical properties of stainless steel and ensure its good welding performance.