Explanation
Heat resistant steel with high chromium content (containing Crl2% -30%) and single-phase ferrite matrix. To improve high-temperature oxidation resistance, small amounts of silicon, aluminum, and rare earth elements can be added. This kind of steel does not have the solid polytype phase transformation of matrix, the thermal conductivity is large, the coefficient of thermal expansion is small, and the surface oxide skin is not easy to peel off, so it has excellent high-temperature oxidation resistance; However, it cannot be strengthened by heat treatment, so its high temperature strength is inferior to that of austenitic heat-resistant steel and martensitic heat resistant steel. In addition, its weld performance is poor, and its room temperature brittleness is large. General ferritic heat-resistant steel is mostly used to manufacture workpieces that need to bear low load but require high oxidation resistance when working at high temperature (that is, it is mainly used as oxidation resistant steel).
Classification
Metals -> Steels -> Alloy steels