用Nd:YAG脉冲激光作为焊接热源,对殷钢材料Invar36分别进行了平板单道焊接试验和对焊试验,分析了工艺参数(激光功率、焊接速度、脉冲宽度和离焦量)变化对焊缝的表面形貌、熔宽以及熔透性的影响。检测了0.85 mm厚的殷钢薄板对焊接头的硬度、成分以及拉伸强度。结果表明:激光功率和脉宽是影响焊缝熔深、熔宽和热影响区面积的主要因素;扫描速度对焊缝表面的鱼鳞状条纹间距影响尤为明显;离焦量主要影响焊缝的宽度和熔透性;合理匹配工艺参数能够实现0.85 mm厚度薄板的对焊,并且获得形貌良好的焊缝。焊缝的组织成分没有发生明显变化,拉伸强度和基体强度相当,显微硬度略低于基体硬度。

A plate-welding test and a butt-welding test for Invar 36 alloy were carried out using Nd:YAG pulsed laser as welding heat source. The effects of process parameters(laser power,welding speed,pulse duration and defocus distance) on the morphology of welding joint,welding width and the penetration were analyzed and the hardness,composition and tensile strength of the fusion zone for butt-welding of 0.85 mm thick Invar sheets were tested. The results indicated that the main factors affecting the weld bead penetration, weld width and Heat Affect Zone(HAZ) are laser power and pulse duration. Moreover,the welding speed effects on the fish-scale spacing and the defocus distance on the weld bead penetration and weld width mainly. Experimental results also indicate that selecting appropriate process parameters can realize the butt-weld for the 0.85 mm thick Invar sheets in good welding modality.The composition of the welding-line has no obviously change, its tensile strength is equal to the base body and its hardness is appreciably lower than that of the base body.