稀土元素对中碳钢组织、力学性能和渗氮的影响

在一种中碳钢中通过添加微量稀土元素,研究稀土微合金化对钢的微观组织、力学性能以及在渗氮热处理条件下对渗层的影响.结果表明,添加稀土后,长条状的MnS夹杂和粗大块状的A12O3转变成小球状的稀土硫氧化物夹杂;铁素体的含量降低,并促进细小片层结构的珠光体形成;冲击性能提升126％以及塑性提高10％;渗氮处理后,添加稀土能显...

Effect of Rare Earth Addition on Microstructure,Mechanical Property and Nitriding Performance of a Medium Carbon Steel

Effect of rare earth microalloying on the microstructure and mechanical property of a medium carbon steel have been investigated, focusing on the influence of rare earth on the formed surface layer after nitriding heat treatment. The results indicate that by adding rare earth elements into the test steel: the original inclusions of long strips of MnS and the coarse Al2O3 convert into the small spherical inclusions of complex rare earth sulfur oxide; the ferrite volume content is reduced ,while more finer lamellar pearlites are formed; the impact energy increases by 126% and the plasticity increases by 10%. After nitriding heat treatment, it is found that the addition of rare earth elements can significantly improve the surface hardness and nitride case depth, as well as improving the vein-like structure of the nitriding layer.