摘要
为了探讨铸坯表层粗大奥氏体晶粒的形成机制,研究了奥氏体晶粒在不同保温条件下的粗化行为。发现由于析出相的影响,高温保温时不同钢种间晶粒生长规律存在差异,且晶粒的进一步粗化在1250℃以下难以有效进行。在此基础上,为了明确装炉温度对加热后奥氏体晶粒结构的影响,对模拟热装再加热过程中的晶粒结构演变进行了试验探究。结果表明,高于珠光体形成温度热装时,轧前奥氏体晶粒结构与冷却前一致;而低于此温度热装时,在奥氏体化后出现大量的新生细小晶粒。后者得到的混晶结构在继续加热至均热温度的过程中发生反常晶粒生长,导致最终组织较冷却前更为粗大。
In order to reveal the evolution of austenite grain structure in continuous casting procedure,the coarsening behavior of austenite grains was studied through the thermal experiments.Due to the influence of precipitates,it was found that the grain growth behaviors of different steel grades are different in high temperature insulation,and the grain size changes little below 1250℃.On this basis,the evolution of austenite grain structure during the reheating process was investigated to reveal the effect of charging temperature on austenite grain structure after slab reheating.The result shows that the grain structure of pre-rolling austenite is consistent with that of pre-cooling when the charging temperature is higher than the pearlite formation temperature.However,when the charging temperature was lower than that,a large number of new fine grains appears after the phase transition.For the latter,abnormal grain growth occurs in the process of continuous reheating,resulting in the eventually larger structure than before cooling.
作者
郑宏光
刘华松
ZHENG Hong-guang;LIU Hua-song(I.Central Research Institute,Baoshan Iron and Steel Co.,Ltd.,Shanghai 201900,China;School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China)
出处
《连铸》
2020年第2期45-51,共7页
Continuous Casting
关键词
连铸
奥氏体
晶粒生长
相变
热装
continuous casting
austenite
grain growth
phase transformation
hot charging
