摘要
采用光学显微镜及透射电镜对热轧板卷的微观组织进行了观察,并利用电子探针对微观化学成分分布进行了分析,结果表明:中心带状组织是由铁索体及珠光体组成的,珠光体层片平均间距约为0.06-0.1μm,而且指出,热轧碳钢的带状微观组织和锰及硅在该组织中的偏析有关.基于相变动力学理论的模拟结果表明:奥氏体热力学稳定性随着Mn的增加而增加,同时铁素体的生长速率降低.由于Mn在铁素体和珠光体边界处的富集、析出,使溶质扩散越发困难,导致奥氏体的分解.由于在钢中加入Mn降低了奥氏体的活性,有利于非平衡相的形成,如珠光体的退化.讨论了热轧板卷中带状组织的成因.
In the present study, the microstructure of hot rolling strips is examined with optical microscopy and transmission electron microscopy. Electron probe microanalysis is also conducted to determine ferrite and pearlite distribution . The average space between carbon lamellas in pearlite is about 0. 006 ～ 0. 1 μm. It is also show that band structue in hot rolled carbon steel is closely related to the segregation of manganese and silicon into those bands. Based on transformation kinet-. ic, the simulation result indicates that the thermodynamic stability of austenite would increase with increasing Mn content, which leads to a decrease in ferrite growth rate. The effect of Mn on decomposition of austenite is attributed to segregation of Mn atoms along the ferrite/austenite interface which causes a strong solute drag effect. The addition of Mn into steel decreases austenite activity, which is beneficial to the formation of non-equilibrium phase such as degenerate pearlite. The formation of the band structure during hot rolling process is also discussed.
出处
《大连铁道学院学报》
2005年第2期75-79,共5页
Journal of Dalian Railway Institute
关键词
珠光体
铁素体
带状微观组织
热轧板卷
pearlite
ferrite
microstructural banding
hot rolling strip
