DP540双相轮辋钢焊接接头组织特征及其不均匀变形研究  

Investigation on Microstructure Characteristics and Inhomogeneous Deformation of Welded Joint of DP540 Dual-phase Steel for Automotive Wheel Rim

作　　者：霍世宗 潘华 丁凯 赵炳戈 雷鸣[4,5] 高玉来 HUO Shizong;PAN Hua;DING Kai;ZHAO Bingge;LEI Ming;GAO Yulai(State Key Laboratory of Advanced Special Steel,Shanghai 200444,China;Shanghai Key Laboratory of Advanced Ferrometallurgy,Shanghai 200444,China;School of Materials Science and Engineering,Shanghai University,Shanghai 200444,China;Automobile Steel Research Institute,R&D Center,Baoshan Iron&Steel Co.,Ltd.,Shanghai 201900,China;State Key Laboratory of Development and Application Technology of Automotive Steels,Shanghai 201900,China)

机构地区：[1]省部共建高品质特殊钢冶金与制备国家重点实验室,上海200444 [2]上海市钢铁冶金新技术开发应用重点实验室,上海200444 [3]上海大学材料科学与工程学院,上海200444 [4]宝山钢铁股份有限公司研究院汽车用钢研究所,上海201900 [5]汽车用钢开发与应用技术国家重点实验室,上海201900

出　　处：《上海金属》2019年第5期26-31,共6页Shanghai Metals

基　　金：国家自然科学基金(No.U1760102)

摘　　要：利用金相显微镜(OM)和扫描电子显微镜(SEM)研究了DP540双相钢闪光对焊接头各特征区域的组织。利用显微维氏硬度计和万能拉伸试验机测量了焊接接头的硬度和拉伸性能。研究发现:DP540双相钢闪光对焊接头存在5个特征区域,分别为焊接界面区、粗晶区、再结晶区、部分再结晶区和母材,其中界面区的硬度最高。焊接接头的屈服强度为464 MPa,抗拉强度为517 MPa,断后伸长率为21.5%,试样在应变为8.5%时发生缩颈,断裂位置处于粗晶区。利用IPP分析软件统计了焊接接头各特征区铁素体和马氏体两相的比例,结果表明,不同特征区两相比例的差异是造成DP540双相钢焊接接头在拉伸过程中产生不均匀变形的主要原因。Microstructure characteristics of the flash butt welded joints of DP540 dual-phase steel were investigated by optical microscope(OM)and scanning electron microscope(SEM).The hardness and tensile mechanical properties of welded joints were measured with the microhardness tester and universal tensile testing machine.The results showed that there were five characteristic zones in the flash butt welded joint of DP540 dual-phase steel,namely weld interface zone,coarse-grained zone,recrystallization zone,incomplete recrystallization zone and base metal,and the hardness of interface zone was the highest.The welded joint provided yield strength of 464 MPa,tensile strength of 517 MPa and elongation of 21.5%.The specimen necked at 8.5%strain and fractured in the coarse-grained zone.The field proportions of ferrite to martensite in each characteristic zone of welded joint were calculated by using the image-pro plus(IPP)analysis software.The results showed that the difference of the ratio of one phase to another in different characteristic zones was the main cause of the inhomogeneous deformation of the DP540 dual-phase steel welded joint during the tensile process.

关 键 词：闪光对焊 DP540双相钢 焊接特征区 两相比例 不均匀变形 

分 类 号：TG1[金属学及工艺—金属学]