钛合金激光-TIG复合焊接保护状态对焊缝成形及性能影响

Effect of protection condition on forming and performance of weld in titanium alloy laser-TIG hybrid welding

关键词:  激光-TIG复合焊  钛合金  接头性能  接头保护

Key words:  laser-TIG hybrid welding  titanium alloy  weld seam performance  weld protection

摘要:

用激光-TIG复合热源对2.5 mm厚TA15钛合金进行对接焊试验.利用万能力学拉伸机、红外热成像仪、电子探针（EPMA）、扫描电镜（SEM）等分析手段对焊接接头进行测试分析，并与单TIG焊进行对比.分析焊接工艺参数和接头保护时间对焊接接头形貌和性能的影响.结果表明，实现2.5 mm厚钛合金全熔透焊接时，激光-TIG复合焊比单TIG焊速度更快、热输入更低，焊缝和热影响区更窄，晶粒更细；相同保护条件下，激光-TIG复合焊接头比单TIG焊接头具有更高的强度、塑性和更好的疲劳性能；激光-TIG复合焊缝冷却速率高于单TIG焊，获得良好的保护状态时所需保护时间更短.

Abstract:

Laser-TIG hybrid experiments were carried out for butt weld of the TA15 titanium alloy sheets with 2.5 mm thick. Multifunction tensile testing machine, infrared thermometer, EPMA and SEM were used to analyze the weld joints, and a comparison with single TIG was made. Welding process, joint performance and weld protection were investigated. Results show that compared with single TIG welding, when full penetration welding of Ti alloy with 2.5 mm thick is realized, laser-TIG hybrid welding possesses faster welding speed and lower heat input, which leads to a narrower and a finer microstructure.Laser-TIG hybrid welding produces weld joints with higher strength, plasticity and better fatigue performance. And because the cooling rate of laser-TIG hybrid welding is higher than that of single TIG, it needs shorter time of protection to achieve good results.