Effect of rare-earth element Cerium on microstructure and properties of stainless steel for precision die

In order to improve the performance of stainless steel for precision corrosion-resistant die, rare earth element Ce with mass fraction of 0.002% was added to 3Cr13 martensitic stainless steel. After quenching and tempering, the effects of rare earth element on the microstructure and mechanical properties of 3Cr13 martensitic stainless steel were studied by means of metallographic observation, SEM, tensile test, impact test and hardness test. The results show that rare earth element can refine the martensite microstructure after quenching and tempering, make its grain size tend to be consistent, and the distribution of "white block area" martensite is more uniform. In terms of mechanical properties, an appropriate amount of rare earth element increased the yield strength and tensile strength of the test steel by more than 100 MPa, the low-temperature impact toughness at 0 ℃ by 62 J/cm², and the hardness value by 48 HV₁₀. At the same time, rare earth element changes the fracture morphology of the low-temperature impact sample of the test steel, reduces the "hole" defects caused by inclusions, hinders the crack propagation, and improves the low-temperature impact toughness of the test steels.