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本文研究了原始组织分别为“回火马氏体”和“回火冷轧马氏体”的10Mn CrNi Mo V钢亚温退火过程中奥氏体的形成。研究结果表明:奥氏体形成是形核和长大的过程。奥氏体优先在位于铁素体晶界和铁素体板条界上的碳化物处形核。奥氏体长大,在较低的亚温退火温度下,由晶界扩散控制,而在较高的亚温退火温度下,则由体积扩散所控制。亚温退火过程中发生锰的再分配,在奥氏体/铁素体界面上锰浓度有极大值,而在邻近的铁素体中的锰浓度有极小值,它减慢奥氏体的长大速度并控制显微组织的均匀化。奥氏体形态对原始组织很敏感,当原始组织为“回火马氏体”时,奥氏体为纤维状和半网状的混合形态;当原始组织为“回火冷轧马氏体”时,奥氏体为等轴状。
In this paper, the formation of austenite during the sub-temperature annealing of 10Mn CrNiMov steel with “Ti-tempered martensite” and “tempered martensite” respectively was studied. The results show that the formation of austenite is the process of nucleation and growth. Austenite preferentially nucleates at the carbide located on the boundary between ferrite grain boundaries and ferrite slabs. Austenitic growth is controlled by grain boundary diffusion at lower sub-temperature annealing temperatures and by volume diffusion at higher sub-temperature annealing temperatures. Manganese redistribution occurs in the subwarm anneal, with a maximum manganese concentration at the austenite / ferrite interface and a minimum in the adjacent ferrite, which slows austenite The growth rate and control the microstructure homogenization. Austenitic morphology is very sensitive to the original organization, when the original organization is “tempered martensite”, austenite is a mixed morphology of fibrous and semi-meshed; when the original organization is “tempered cold-rolled martensite” Austenite is equiaxed.