ISSN: 1003-6326
CN: 43-1239/TG

Vol. 27    No. 1    January 2017

Stitch welding of Ti-6Al-4V titanium alloy by fiber laser
Cui LI1, Bin LI2, Ze-feng WU1, Xiao-yong QI1, Bing YE1, Ai-hua WANG1,2
(1. Hubei Provincial Key Laboratory of Laser Advanced Manufacturing Technology,
Wuhan Huagong Laser Engineering Co., Ltd., Wuhan 430223, China;
2. School of Mechanical Science and Engineering,
Huazhong University of Science and Technology, Wuhan 430074, China
Abstract: Stitch welding of plate covered skeleton structure of Ti-6Al-4V titanium alloys has a variety of applications in aerospace vehicle manufacture. The laser stitch welding of Ti-6Al-4V titanium alloys was carried out by a 4 kW ROFIN fiber laser. Influences of laser welding parameters on the macroscopic geometry, porosity, microstructure and mechanical properties of the stitch welded seams were investigated by digital microscope, optical microscope, scanning electron microscope and universal tensile testing machine. The results showed that the three-pipe nozzle with gas flow rate larger than 5 L/min could avoid oxidization, presenting better shielding effect in comparison with the single-pipe nozzle. Porosity formation could be suppressed with the gap between plate and skeleton less than 0.1 mm, while the existing porosity can be reduced with remelting. The maximum shear strength of stitch welding joint with minimal porosity was obtained by employing laser power of 1700 W, welding speed of 1.5 m/min and defocusing distance of +8 mm.
Key words: Ti-6Al-4V titanium alloy; fiber laser; stitch welding; welding parameter; porosity
Superintended by The China Association for Science and Technology (CAST)
Sponsored by The Nonferrous Metals Society of China (NFSOC)
Managed by Central South University (CSU)