摘要
采用光学显微镜、扫描显微镜、维氏硬度仪、微拉伸试验机和低温冲击试验机对水电钢07MnCrMoVR焊接接头的组织和性能进行了研究.结果表明:焊缝处的金相显微组织为先共析铁素体+针状铁素体+贝氏体,维氏显微硬度值较低;热影响粗晶区存在粗大的粒状贝氏体,具有较高的显微硬度,热影响细晶区组织为多边形铁素体和针状铁素体,显微硬度值低于热影响粗晶区.热影响粗晶区的微拉伸强度最高,-20℃低温冲击韧性最差,主要是因为热影响粗晶区存在的粗大粒状贝氏体组织,其高硬度的M/A岛在承受低温冲击时成为裂纹扩展的源头,可能导致焊接接头出现脆断的现象,实际生产中应尽量避免热影响粗晶区出现粗大的粒状贝氏体.
The weld-joint microstructure and properties of hydropower steel 07MnCrMoVR were studied in this paper by using optical microscope,scanning electron microscope,Vickers hardness tester,micro-tensile tester and low-temperature impact toughness tester.The results showed that the microstructure of weld seam consists of proeutectoid ferrite,acicular ferrite and bainite with low Vickers hardness.Coarser bainite with high Vickers hardness exists in the coarse grain heat affected zone.The fine grain heat affected zone mainly consists of polygonal ferrite and acicular ferrite,and the micro-hardness is lower,compared with the coarse grain zone.The coarse grain heat affected zone has the highest tensile strength and the worst-20℃low temperature impact toughness.This is possibly related to the coarse bainite in the coarse grain heat affected zone,where hard M/A islands behaves as crack source under low-temperature impact,causing brittle fracture.Therefore,the coarse bainite should be avoided as far as possible in the coarse grain heat affected zone during industrial production.
作者
冯路路
刘玲
乔文玮
鲁修宇
Feng Lulu;Liu Ling;Qiao Wenwei;Lu Xiuyu(School of Mechanical Engineering,Jing Chu University of Technology,Jingmen 448000,Hubei,China;Collaborative Innovation Center for Advanced Steels,Wuhan University of Science and Technology,Wuhan 430081,China;Jiangsu Huaneng Cable Co.Ltd.Gaoyou 225613,Jiangsu,China;Research Institute of Wuhan Iron&Steel Group,Wuhan 430080,Hubei,China)
出处
《材料与冶金学报》
CAS
北大核心
2020年第3期222-226,共5页
Journal of Materials and Metallurgy
基金
荆楚理工学院校级科学研究项目(YB201902,PY202004)
高压科学与先进超硬复合材料科研团队(TD201906).
