What is the role of heat resistant steel

The formation of chromium, aluminum and silicon elements, at high temperature can promote the formation of a dense metal surface oxide film, to prevent further oxidation, is to improve the oxidation resistance of steel and high temperature gas corrosion of the main elements. However, the high content of aluminum and silicon will cause serious deterioration of the room temperature plasticity and thermal plasticity. Chromium can significantly improve the recrystallization temperature of low alloy steel, and the effect is best when the content is 2%.

Nickel and manganese can form and stabilize austenite. Nickel can improve the high temperature strength of austenitic steel and improve the resistance to carburizing. Although manganese can form austenite, the oxidation resistance of heat resistant steel is impaired.

Vanadium, titanium and niobium are strong carbide forming elements, which can form fine dispersed carbide and increase the high temperature strength of steel. The combination of titanium and niobium with carbon can prevent the corrosion of austenitic steel at high temperature or after welding.

Carbon and nitrogen can expand and stabilize austenite, so as to increase the high temperature strength of heat resistant steel. Steel containing chromium and manganese is large, can significantly improve the solubility of nitrogen, and available nitrogen alloying to replace expensive nickel.

Boron and rare earth are trace elements in heat resistant steel. Boron dissolved in solid solution in the crystal lattice distortion, and can prevent the grain boundary of the boron element diffusion and grain boundary migration, so as to improve the high-temperature strength of steel; rare earth elements can significantly improve the oxidation resistance of steel, improve the thermoplastic.