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在中碳锰钒钢中加入稀土元素。研究了稀土对钢连续冷却转变的影响。研究发现,稀土增加了过冷奥氏体的稳定性,使CCT曲线右移,延长了先共析铁素体、珠光体、上贝氏体转变的孕育期。但对下贝氏体转变没有影响。稀土影响了正火后钢的组织形态,抑制了铁素体—珠光体反应,产生了粒状贝氏体,并影响了正火时碳化物的析出。研究认为,固溶于钢中的稀土元素处于内吸附状态,阻碍了新相在晶界处的形核过程,因而提高了过冷奥氏体的稳定性。
In the carbon-manganese vanadium steel by adding rare earth elements. The effect of rare earth on continuous cooling transformation was studied. The results show that rare earth increases the stability of supercooled austenite and shifts the CCT curve to the right, which prolongs the incubation periods of proeutectoid ferrite, pearlite and upper bainite. But has no effect on the lower bainite transformation. Rare earth affects the morphology of the steel after normalizing, suppresses the ferrite-pearlite reaction, produces granular bainite and affects the precipitation of carbides during normalizing. The results show that rare earth elements dissolved in steel are in adsorption state, which hinders the nucleation process of new phase at the grain boundary, which improves the stability of undercooled austenite.