研究了不同稀土含量对20Mn钢等温相变及组织形态的影响。随钢中稀土含量的增加,先共析铁素体析出的孕育期缩短,完成珠光体相变所需时间延长;针状铁素体量减少直至消失;珠光体片间距变密且相对转变量减少;粒状贝氏体中碳化物易于偏聚。稀土减小原奥氏体晶界能和相界面能,稀土原子偏聚在相界面上阻碍碳原子的扩散,以及可能形成高熔点稀土碳化物而减少奥氏体中碳的固溶量,是产生上述结果的主要原因。 The effects of different RE content on isothermal transformation and microstructure of 20Mn steel were studied. With the increase of rare earth content in the steel, the incubation period of the pro-eutectoid ferrite is shortened, the time required to complete the pearlite transformation is prolonged, the amount of acicular ferrite decreases until it disappears, and the spacing of the pearlite pieces becomes dense and the relative transformation amount Reduce; granular bainite carbides prone to segregation. Rare earth reduce the original austenite grain boundary energy and phase interface energy, rare earth atoms segregate in the phase interface impede the diffusion of carbon atoms, as well as the possible formation of high melting point rare earth carbide and reduce the amount of carbon in austenite solid solution is The main reason for the above results.