EH40船板钢奥氏体晶粒长大及连续冷却相变规律  

Austenite grain growth and continuous cooling phase transformation of EH40 ship plate steel

作　　者：厉文墨 刘芳芳 王佳骥 蒋健博 江坤 Li Wenmo;Liu Fangfang;Wang Jiaj;Jiang Jianbo;Jiang Kun(State Key Laboratory of Metal Material for Marine Equipment and Application,Anshan Liaoning 114009,China;Ansteel Beijing Research Institute,Beijing 102209,China)

机构地区：[1]海洋装备用金属材料及其应用国家重点实验室,辽宁鞍山114009 [2]鞍钢集团北京研究院,北京102209

出　　处：《金属热处理》2023年第12期189-193,共5页Heat Treatment of Metals

基　　金：鞍钢股份项目(2022BJB-02GF)。

摘　　要：采用Gleeble-3800热模拟试验机对EH40船板钢进行热模拟试验,通过金相显微镜(OM)、维氏硬度计等设备,分析了奥氏体晶粒尺寸随加热温度升高的粗化行为及不同冷却速度下EH40钢的组织演变与硬度变化。结果表明,奥氏体粗化温度在1200℃以上,奥氏体经950℃保温后冷却,未变形时,在0.5~1℃/s的冷速范围内,组织主要由铁素体与珠光体构成;当冷速达到2℃/s后,组织中开始出现粒状贝氏体与板条贝氏体;随着冷速持续增大,板条贝氏体比例逐渐上升并均匀化,板条形貌逐渐细化,基体硬度由157 HV5提高至214 HV5;经60%变形后,与未变形时相比,EH40钢的晶粒发生明显细化,钢中铁素体相变区扩大,基体硬度由164 HV5提高至234 HV5。Gleeble-3800 testing machine was used to conduct thermal simulation tests on EH40 ship plate steel. The coarsening behavior of austenite grain and the microstructure evolution at different heating temperatures were observed by metallographic microscope(OM). The hardness change of EH40 steel at different cooling rates was analyzed using Vickers hardness tester. The results show that the coarsening temperature of austenite is above 1200 ℃. The microstructure of austenite at 950 ℃ and undeformation is mainly composed of ferrite and pearlite in the cooling rate range of 0.5-1 ℃/s without deformation after holding at 950 ℃. When the cooling rate reaches 2 ℃/s, granular bainite and lath bainite are observed in the microstructure. With the increase of cooling rate, the lath bainite proportion gradually increases and is homogenized, the morphology of lath gradually refines, and the matrix hardness increases from 157 HV5 to 214 HV5. After 60% deformation, the grain of EH40 steel is finer than that of the undeformed steel, the ferritic phase transformation zone is enlarged, and the matrix hardness is increased from 164 HV5 to 234 HV5.

关 键 词：冷却速度 EH40钢 组织演变 硬度 奥氏体晶粒长大 

分 类 号：TG161[金属学及工艺—热处理]