以低合金调质高强钢为研究对象，采用Nd:YAG激光器进行激光-电弧复合焊接试验。利用金相显微镜、扫描电子显微镜、X射线衍射仪、显微硬度测试仪、拉伸试验机等设备，对高强钢焊接接头进行微观组织研究、力学性能和断口分析。结果表明，焊缝区、热影响区和母材区均为板条马氏体组织；显微硬度结果显示焊接接头热影响区硬度在480～530 HV之间，焊缝区在470～500 HV之间，软化区硬度低于350 HV。在焊缝区没有缺陷的情况下均在软化区断裂，断裂形式为典型的韧窝断裂，拉伸强度最高达到1 202 MPa。

High-strength steel as the research object was studied, and the laser-arc hybrid welding test was carried out by using Nd:YAG laser. Microstructure, mechanical properties and fracture analysis of high strength steel welded joint were investigated by optical microscope, scanning electron microscope, X-ray diffraction, micro hardness tester and tensile testing machine. The results show that weld zone, heat effected zone and base metal are composed of lath martensite. Micro-hardness results show that the hardness of hot effected zone is between 480～530 HV, the hardness of the weld zone is between 470～500 HV and the hardness of The softening zone is less than 350 HV. The softening zone is broken under the condition of no defect in weld, the fracture mode is the typical ductile fracture and the tensile strength is up to 1 202 MPa.