高速列车不锈钢车体点焊接头疲劳断裂分析及疲劳性能对比研究  

Comparison of fatigue property and analysis on spot welded joint of stainless steel body in high speed train

作　　者：韩晓辉[1] 赵延强[1] 王素环[1] 刘伟[2] 

机构地区：[1]南车青岛四方机车车辆股份有限公司,266000 [2]北京交通大学机械与电子控制工程学院,100044

出　　处：《焊接》2013年第8期33-36,71,共4页Welding & Joining

基　　金：863项目(No.2008AA030702)

摘　　要：选取高速列车不锈钢车体应力集中区域的3组典型点焊接头进行脉动拉伸疲劳试验，对点焊疲劳试样的裂纹起源、断裂方式及裂纹形态进行分析研究，并对高速列车用不同强度级别不锈钢点焊接头的抗疲劳性能进行评定。研究结果表明：点焊试件具有严重结构应力集中，疲劳断裂方式为穿板断裂，疲劳裂纹起源于点焊热影响区根部、两层板接合面处，随着点焊疲劳裂纹扩展，沿着焊点热影响区切线方向向两侧母材厚度方向扩展。冷轧不锈钢板的疲劳极限与其强度等级关系较大，低强度级别的301L—DLT板点焊工艺性好，优质点焊接头的疲劳极限约为静拉剪强度的10％～15％；高强度级别的301L—HT板点焊工艺性较差，疲劳极限不足静拉剪强度的10％。Three group of typical spot welded joints on the stress concentration region were studied by the pulse tensile-fatigue test for stainless steel body in high speed train.The crack origin,fracture mode and crack morphology of the spot welding fatigue specimens were studied and analyzed.Fatigue proerty of spot welded joint of different grades stainless steel were evaluated.The results indicate that there is serious stress concentrationspot welding structure,and the fatigue fracture mode is puncture plate fracture originated from the root of origin heat affected zone(HAZ) and the joint of two plates.With the fatigue crack of spot welding extend along the tangential direction of HAZ to the thickness direction of base metals.There is great difference between fatigue limit and strength grade of cold rolling stainless steel plate,and spot weldability of low strength grade of 301L-DLT plate is good.The fatigue limit of high quality spot welded joint is about 10%-15%of static tensile-shear strength.Spot weldability of high strength grade of 301L-DLT plate is poor,and the fatigue limit is lack of 10%of static tensile-shear strength.

关 键 词：不锈钢 点焊接头 疲劳断裂 疲劳性能 

分 类 号：TG405[金属学及工艺—焊接]