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对8.0mm厚低合金高强钢采用激光-MAG复合焊接,取5组不同比例保护气体(CO2+Ar),研究焊接工艺特性,对接头硬度、拉伸、弯曲、冲击性能进行分析,并从断口特征方面对其断裂原因和机制进行研究。结果表明,保护气体对工艺特性及硬度影响较大。焊接接头拉伸强度足够,均在母材处拉断,拉伸断口形貌为较为粗大的韧窝。正弯断口大多为细小韧窝,背弯断口大多为粗大韧窝和部分解理面。焊缝区冲击功低于热影响区,保护气体比例和冲击温度对接头冲击韧性影响较大。
The laser-MAG composite welding of 8.0mm thick low-alloy high-strength steel was carried out. Five different proportions of protective gas (CO2 + Ar) were used to study the welding process characteristics. The joint hardness, tensile, bending and impact properties were analyzed. Characteristics of its fracture causes and mechanisms for research. The results show that the protective gas has a great influence on the process characteristics and hardness. Tensile strength welded joints are sufficient, are broken off at the parent material, tensile fracture appearance of the larger dimples. Are bending the mouth mostly small dimples, most of the back bend bend dimples and part of the cleavage plane. The impact energy of weld zone is lower than that of heat affected zone, and the ratio of protective gas and impact temperature have a greater impact on the impact toughness of joint.