Fiber laser welding of thick AISI 304 plate in a horizontal (2G) butt joint configuration

Publication date: 15 March 2017
Source:Materials & Design, Volume 118
Author(s): Junhao Sun, Kai Feng, Ke Zhang, Baochao Guo, En Jiang, Pulin Nie, Jian Huang, Zhuguo Li
An innovative laser technique has been developed for welding 16mm thick 304L stainless steel in the horizontal (2G) butt joint configuration. Autogenous laser welding (ALW) was applied to join the thick plate with a square groove and zero air gap, and laser welding assisted with a cold wire (LWACW) was used to fill the unfilled joint. The dimension of the square groove was optimized to achieve full penetration joint with smooth reinforcement at the back side. The wire feed process was also optimized to produce a sound weld appearance. The microstructure and mechanical properties were observed and evaluated by optical microscope, electron backscatter diffraction, microhardness measurement and tensile test. The results showed that the square groove contributed to produce a joint with deeper penetration and narrower width. The relative position of weld wire with respect to the laser spot had a great influence on the weld appearance. Sound appearance with defect-free joint was successfully produced for the 16mm thick plate in the horizontal position. The microstructure and microhardness of the top and middle samples are different, resulting in the different tensile strength and fractured location.

Graphical abstract

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