High strength, but poor plasticity and weldability. The commonly used grades of martensitic stainless steels are 1Cr13, 3Cr13, etc., because of the high carbon content, they have high strength, hardness and wear resistance, but the corrosion resistance is slightly poor, which is used for high mechanical properties and corrosion resistance. General parts are required, such as springs, steam turbine blades, hydraulic valve valves, etc. This type of steel is used after quenching and tempering. Annealing and annealing are required after stamping.