摘要
本文采用热模拟实验、光学显微镜、透射电镜等技术研究了12CrlMoV耐热钢的热装温度和变形对其组织和析出的影响。通过对实验钢的热膨胀曲线和金相分析发现,在650-800℃的热装温度下,一次冷却和保温的过程中,部分奥氏体相变成为铁素体和贝氏体,保温结束后的组织为铁素体+贝氏体+未转变奥氏体。在随后的二次奥氏体化的过程中,铁素体和贝氏体逆转变形成尺寸较小的奥氏体晶粒;原先未转变的奥氏体则继续长大,形成尺寸较大的奥氏体晶粒,从而出现奥氏体晶粒大小不均匀的“奥氏体混晶”现象。并且在此温度区间出现了大量的V、Ti大尺寸析出物,从而大幅降低后续轧制过程中的韧塑性。因此12CrlMoV钢的热装温度应尽量避开此温度区间。
In this paper,thermal simulation experiments,optical microscopy(OM),transmission electron microscopy(TEM)and other techniques are used to study the effects of hot charging temperature and deformation of 12Cr1MoV heat-resistant steel on its structure and precipitation.Through the analysis of the thermal expansion curve and metallography of the experimental steel,the results show that at the hot charging temperature of 650-800 C,part of the austenite phase transforms into ferrite and bainite during the primary cooling and heat holding process.The microstructure of ferrite+bainite+untransformed austenite is formed at the end of heat holding.Inthe process of secondary austenitization,ferrite and bainite reversely transform to smaller austenite grains;The untransformed austenite continues to grow,forming larger austenite grains,resultingin a phenomenon of"austenite mixed grains"with uneven grain sizes.And a large number of large-sized precipitates of V and Ti appear in this temperature range,which greatly reduces the ductility and plasticity in the subsequent rolling process.Therefore,the hot charging temperature of 12CrlMoV steel should be set up bypass this temperature range.
作者
韩永锋
梁亮
何冠军
徐光
邓想涛
HAN Yongfeng;LIANG Liang;HE Guanjun;XU Guang;DENG Xiangtao(Hunan Valin Lianyuan Iron&Steel Co.,Ltd.,Loudi 417009,China;The State Key Laboratory of Rolling and Automation,Northeastern University,Shenyang 110819,China;College of Materials and Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,China)
出处
《金属材料与冶金工程》
CAS
2022年第1期47-54,共8页
Metal Materials and Metallurgy Engineering
关键词
耐热钢
热装温度
奥氏体组织均匀性
析出
heat-resistant steel
hot charging temperature
uniformity of austenite structure
precipitation
