细晶Q420低合金高强钢焊接接头组织性能研究
Study on Microstructure and Properties of Welded Joint of Fine-grained Q420 High Strength Low Alloy Steel
杜宝帅， 张忠文， 李新梅， 彭宪友
点击：3598次 下载：0次
作者单位：（山东电力研究院，山东 济南 250002）
中文关键字：低合金高强钢；焊接；显微组织；力学性能
英文关键字：HSLA steel; welding; microstructure; mechanical properties
中文摘要：采用CO2气体保护焊对细晶Q420低合金高强钢进行焊接，用光学显微镜、扫描电镜分析了焊接接头显微组织及断口形貌，试验测试了焊接接头拉伸、弯曲及冲击性能。结果表明，细晶Q420钢母材由晶粒细小的铁素体和珠光体构成，选用ER55-G焊丝所得焊接接头焊缝金属具有比母材更高的抗拉强度，焊缝及热影响区均具有良好的冲击性能，断口为典型韧窝状延性断裂形态。在所选焊接工艺参数下，其热影响区表现出比焊缝金属更好的冲击性能。
英文摘要：Fine-grained Q420 high strength low alloy steel was welded by CO2 gas shield welding. The optical microscopy and scanning electron microscopy were used to analyze the microstructure and fractographs of the welded joint. The mechanical properties of the joint were also tested. The results show that, the base metal of Q420 steel consists of fine-grained ferrite and pearlite. The welding metal showes higher strength than that of the base metal when ER55-G welding electrode is employed. Both the welding metal and heat affected zone possess good impact toughness. It was found that the ductile fracture with micro-void coalescence appears on the fracture surface. For specimens fabricated using the current welding parameters, the heat affected zone in the fine-grained Q420 steel welded joint exhibits higher impact toughness than that of the welding metal.