稀土元素铈对精密模具用不锈钢组织性能的影响

为了提高精密模具用不锈钢的性能，在3Cr13马氏体不锈钢中添加质量分数为0.002%的稀土元素铈（Ce），经淬火+回火处理后，采用金相观察、SEM、拉伸试验、冲击试验和硬度测试等方法，研究了Ce对3Cr13马氏体不锈钢组织及力学性能的影响。结果表明:Ce能细化淬火+回火后的马氏体组织，使其晶粒大小趋于一致，“白块区”马氏体分布更加均匀，使试验钢屈服强度和抗拉强度提高了100 MPa以上，0 ℃低温冲击韧性提高了62 J/cm2，HV₁₀硬度值提高了48。同时Ce改变了试验钢低温冲击试样的断口形貌，减少了夹杂物引起的“孔洞”缺陷，阻碍了裂纹的扩展，提高了试验钢的低温冲击韧性。 

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.