Fatigue Resistance and Failure Behavior of Penetration and Non-Penetration Laser Welded Lap Joints

作     者：Xiangzhong Guo Wei Liu Xiqing Li Haowen Shi Zhikun Song Xiangzhong Guo;Wei Liu;Xiqing Li;Haowen Shi;Zhikun Song

作者机构：School of MechanicalElectronic and Control EngineeringBeijing Jiaotong UniversityBeijing 100044China 

出 版 物：《Chinese Journal of Mechanical Engineering》 (中国机械工程学报（英文版）)

年 卷 期：2021年第34卷第2期

页      面：97-106页

核心收录：

学科分类：080503[工学-材料加工工程] 08[工学] 0805[工学-材料科学与工程（可授工学、理学学位）] 0802[工学-机械工程] 080201[工学-机械制造及其自动化] 

基　　金：Supported by Scientific Research and Development Projects of China Railway Corporation(Grant No.2017J011-C) 

主　　题：Laser welded lap joint Penetration and non-penetration Fatigue resistance Fracture behavior 

摘      要：Penetration and non-penetration lap laser welding is the joining method for assembling side facade panels of railway passenger cars,while their fatigue performances and the difference between them are not completely *** this study,the fatigue resistance and failure behavior of penetration 1.5+0.8-P and non-penetration 0.8+1.5-N laser welded lap joints prepared with 0.8 mm and 1.5 mm cold-rolled 301L plates were *** weld beads showed a solidification microstructure of primary ferrite with good thermal cracking resistance,and their hardness was lower than that of the *** 1.5+0.8-P joint exhibited better fatigue resistance to low stress amplitudes,whereas the 0.8+1.5-N joint showed greater resistance to high stress *** failure modes of 0.8+1.5-N and 1.5+0.8-P joints were 1.5 mm and 0.8 mm lower lap plate fracture,respectively,and the primary cracks were initiated at welding fusion lines on the lap *** were long plastic ribs on the penetration plate fracture,but not on the non-penetration plate *** fatigue resistance stresses in the crack initiation area of the penetration and non-penetration plates calculated based on the mean fatigue limits are 408 MPa and 326 MPa,respectively,which can be used as reference stress for the fatigue design of the laser welded *** main reason for the difference in fatigue performance between the two laser welded joints was that the asymmetrical heating in the non-penetration plate thickness resulted in higher residual stress near the welding fusion line.