Characteristics of Welding Crack Defects and Failure Mode in Resistance Spot Welding of DP780 Steel

作     者：Xiao-pei WANG Yong-qiang ZHANG Jian-bin JU Jian-qiang ZHANG Jian-wei YANG 

作者机构：Shougang Research Institute of Technology Beijing 100043 China College of ScienceChina University of Petroleum (Beijing) Beijing 102249 China 

出 版 物：《Journal of Iron and Steel Research International》 (钢铁研究学报(英文版))

年 卷 期：2016年第23卷第10期

页      面：1104-1110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] 

主　　题：resistance spot welding mechanical property crack defect failure mode DP780 steel 

摘      要：The mechanical properties of welded joints in resistance spot welding of DP780 steel were tested,and three different types of welding cracks in welded joints were investigated by optical microscopy,scanning electron microscopy and electron back-scattered ***,the failure mode of the welded joints in shear tensile test was *** is found the shear tensile strength of welded joints can be greatly improved by adding preheating current or tempering *** surface crack in welded joint is intergranular fracture,while the inner crack in welded joint is transgranular fracture,and the surface crack on the edge of the electrode imprint can be improved by adding preheating current or tempering *** traditional failure mode criterion advised by American Welding Society is no longer suitable for DP780 spot welds and the critical nugget size suggested by Pouranvari is overestimated.