420 MPa级轮辋用钢焊接变形失效原因浅析  

Brief Analysis on Deformation Failure of Welding for 420 MPa Grade Steel for Rim

作　　者：张智刚 宿成[1] 杨维宇[1] 李鹏[1] Zhang Zhi-gang;Su Cheng;Yang Wei-yu;Li Peng(Technical Center of Inner Mongolia Baotou Steel Union Co.,Ltd.,Baotou 014010,Inner Mongolia Autonomous Region,China)

机构地区：[1]内蒙古包钢钢联股份有限公司技术中心,内蒙古包头014010

出　　处：《包钢科技》2023年第5期61-65,共5页Science & Technology of Baotou Steel

摘　　要：某车轮厂冬季采购一批420CL钢加工汽车轮辋过程中保留钢卷“轧制圆边”的轮辋边缘发生焊接变形开裂。使用金相显微镜和显微硬度计检测轮辋开裂边缘和对应未开裂边缘的金相组织和显微硬度,分析开裂原因。保留钢卷“轧制圆边”的轮辋边缘的焊缝、热影响粗晶区、热影响细晶区以及母材显微硬度分别为217、215、223、150,没有钢卷“轧制圆边”的轮辋边缘的焊缝、热影响粗晶区、热影响细晶区以及母材的硬度分别为222、230、235和220,发生开裂的轮辋边部焊接热影响区与母材显微硬度相差约70,这是导致轮辋开裂的主要原因。闪光对焊后,沿轮辋边缘焊接热影响细晶区与未受焊接热影响的材料硬度相差太大,破坏了轮辋边缘变形协调能力,在结合处产生应力集中引发开裂。During the process of manufacturing automobile rims by purchased 420CL steel of one wheel plant in the winter,there is welding deformation cracking at edge of the rims with remained“rolled round edge”of steel coils.The metallographic structure and microhardness of edges with and without cracking of rim are detected with metalloscope and microhardness tester respectively as well as the causes of cracking are analyzed.The values of microhardness of weld seam,coarse grain heat affected zone,fine grain heat affected zone and parent metal at edge of the rims with remained“rolled round edge”of steel coils are 217,215,223 and 150 respectively,while those without“rolled round edge”of steel coils are 222,230,235 and 220 respectively.The difference of microhardness for welding heat affected zone and parent metal at edge of the rim with cracking is about 70,this is the main cause for cracking of rim.After flash butt welding,the difference of material hardness for welding fine grain heat affected zone and without welding heat effect along edge of rim is too large so that the deformation coordination ability at edge of rim is destroyed and the stress concentration is generated at juncture to cause cracking.

关 键 词：420CL钢 闪光对焊 变形开裂 显微硬度 金相组织 

分 类 号：TG457.11[金属学及工艺—焊接]