12Cr1MoV耐热钢热装热送过程相变行为及组织研究

Study on the transformation behavior and microstructure during hot-charging rolling process in a 12Cr1MoV heat-resistance steel

连铸坯热装热送轧制工艺是一种有效的节能减排工艺,该工艺生产时偶尔出现表面质量问题,导致轧制过程中钢板表面开裂。针对这一问题,采用热模拟试验机模拟了12Cr1MoV耐热钢热装热送加热轧制生产工艺,利用金相法来观察试样组织。结果表明,当热装温度在两相区温度以下或以上时,最终组织中有较多铁素体和较少粒状贝氏体+M/A;当热装温度在两相区温度区间内时,最终组织为少量铁素体和大量粒状贝氏体+M/A。此外,在两相区热装后,经二次高温奥氏体化形成'奥氏体混晶'不均匀,在变形时容易产生应力集中,容易导致裂纹的萌发。

The hot-charging rolling process of continuous casting billets is an effective process of steel production for energy saving and emission reduction.In actual production,there are problems such as poor surface quality and cracks during rolling.In the present investigation,the hot-charging rolling process of 12Cr1MoV heat-resistance steel was simulated.The thermal simulation experiment was conductedon a thermal simulator,and the microstructure was observed by metallographic method.The results show that when the charging temperature was below and abovethe intercritical region,the microstructure consisted of more ferrite and less bainite+M/A.When the charging temperature was in the intercritical region,the microstructure consisted of less ferrite and more bainite+M/A.In addition,the'austenitic mixed crystal'formed by secondary high temperature austenitization were not uniform,and the stress concentration tended to occur during deformation,resulting in cracks on the surface of the rolled steels.