SMA490BW钢激光-MAG复合焊T型接头疲劳性能  

Fatigue performance of laser-MAG hybrid welding T joint on SMA490BW steel

作　　者：饶清鹏[1] 吴向阳[2] 陶传琦[2] 齐维闯[2] 徐良[3] 史春元[1] 杜兵[3] 

机构地区：[1]大连交通大学材料科学与工程学院,辽宁大连116028 [2]南车青岛四方机车车辆股份有限公司技术工程部,山东青岛266111 [3]机械科学研究总院哈尔滨焊接研究所,黑龙江哈尔滨150080

出　　处：《电焊机》2014年第10期158-163,共6页Electric Welding Machine

摘　　要：对激光-MAG复合焊和MAG焊T型接头进行了四点弯曲疲劳试验,采用最小二乘法拟合疲劳S-N曲线,估算了两种焊接方法 T型接头循环寿命为107时的疲劳强度。试验结果表明,当循环基数为107次时,激光-MAG复合焊接头的疲劳强度较常规MAG焊接头提高17.5%。观察两种焊接方法的疲劳断口发现,断口位置在熔合区的焊趾处,裂纹扩展区疲劳辉纹明暗相交,既短又不连续,呈韧性疲劳断口特征。但激光-MAG复合焊疲劳裂纹扩展区撕裂棱凸出较大,裂纹扩展时所需的动力更大,断裂韧性更高。分析发现,焊趾处圆滑过渡和细小的熔合区微观组织导致激光-MAG复合焊T型接头的疲劳强度高于MAG焊。Based on T joint four-point bending fatigue experiment of Laser-MAG hybrid welding and MAG welding process,the fatigue strength under cycle life of 107 were calculated respectively by the least square method and S-N curves were drawn.The results indicate that the fatigue strength of Laser-MAG hybrid welding is higher by 17.5% than that of conventional MAG welding when the cycle life is 107.The fatigue fracture analysis revealed that fatigue crack is located welding toe of bond area and toughness fatigue fracture characteristics were observed because fatigue striations of crack propagation region were found short and discontinuous. However,the toru edges bulge of Laser-MAG hybrid welding is larger than that of MAG welding.This shows the crack extension of Laser-MAG hybrid welding is more difficult and the crack toughness is higher. Due to the smooth transition of welding toe and small microstructure of bond area,the T joint fatigue strength of Laser-MAG hybrid welding is higher than that of MAG welding.

关 键 词：激光-MAG复合焊 疲劳强度 应力集中系数 疲劳断口分析 

分 类 号：TG456.7[金属学及工艺—焊接]