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Pros and cons of the role of alloying elements in stainless steel

Sep 12, 2019

    Iron (Fe): is the basic metal element of stainless steel;

    Chromium (Cr): It is the main ferrite forming element. The combination of chromium and oxygen can form a corrosion-resistant Cr2O3 passivation film, which is one of the basic elements of stainless steel to maintain corrosion resistance. The increase of chromium content can improve the passivation film repair of steel. Capacity, generally the chromium content in stainless steel must be above 12%;

    Carbon (C): is a strong austenite forming element, which can significantly increase the strength of steel, and carbon also has an adverse effect on corrosion resistance;

    Nickel (Ni): is the main austenite forming element, which can slow down the corrosion phenomenon of steel and the growth of crystal grains during heating;

    Molybdenum (Mo): It is a carbide forming element. The formed carbide is extremely stable. It can prevent grain growth when austenite is heated and reduce the heat sensitivity of steel. In addition, molybdenum can make the passivation film more dense. Firm, thus effectively improving the resistance of stainless steel to Cl-corrosion;

    Niobium, titanium (Nb, Ti): is a strong carbide forming element, which can improve the resistance of steel to intergranular corrosion. However, titanium carbide has an adverse effect on the surface quality of stainless steel. Therefore, in stainless steel with high surface requirements, the addition of niobium is generally used to improve the performance.

    Nitrogen (N): is a strong austenite forming element that can significantly increase the strength of steel. However, the effect of ageing cracking on stainless steel is large, so the nitrogen content should be strictly controlled in stainless steel for stamping purposes.

    Phosphorus, sulfur (P, S): is a harmful element in stainless steel, which will adversely affect the corrosion resistance and stamping properties of stainless steel.