超薄钛壳激光焊接工艺参数对焊缝成形影响研究

Study on Effects of Process Parameters on Laser Seal Welding for Ultra Thin Titanium Shell

受加工工艺、热变形等因素影响,超薄钛壳的密封焊接存在较大的困难。采用Nd:YAG脉冲激光器对0.3mm厚的钛壳进行激光密封焊接,详细研究了激光焊接过程中脉冲激光波形、激光功率、焊接速度、离焦量、侧吹气体流量等工艺参数对焊接成形质量的影响,随后对0.3mm厚的搭接接头进行了显微硬度测量与显微组织分析,最后采用氦质谱检漏对焊接样品进行了漏率测量。试验结果表明:平稳的焊接波形是获得优质密封焊接效果的良好选择;激光功率和焊接速度的合理匹配是保证焊接质量的必要条件;当采用侧吹气体流量为15L/min时,气体保护效果良好。通过一系列的工艺试验,总结出超薄钛壳的工艺焊接规程,为实际工程应用和优化密封焊接过程提供参考。

Due to the effects of manufacture techniques on specimen and heat distortion during welding,seal welding for ultra thin titanium shell is quite difficult.An Nd： YAG pulse laser system was used to seal 0.3mm thick medical titanium implant herein.The effects of process parameters including pulse wave shape,laser power,welding speed,defocusing amount,and shielding gas were investigated.Besides,tests of micro-hardness and micro-structure analyses on overlapped weld joint were discussed.Finally,parts of the welded specimens were analyzed by helium mass spectrum leakage detector.The experimental results show that flat wave shape is optimum choice for seal welding,reasonable collocation of laser power and welding speed guarantees the welding quality,and the weld bead color is good when the shielding gas flow rate is at 15 L/minute.The welding specification for sealing ultra thin titanium shell was confirmed through a serial of technique experiments.It provides reference for engineering applications and optimization of the seal welding further.