Product Code: PIC2008_706

A Comparison of the Pitting Corrosion Behavior of 304L Stainless Steel by Tig, Laser and Laser-Tig Hybrid Welding
Authors:
Jun Yan, Huazhong University of Science and Technology,; Wuhan Peoples Republic of China
Ming Gao, Huazhong University of Science and Technology,; Wuhan Peoples Republic of China
Xiaoyan Zeng, Huazhong University of Science and Technology; Wuhan Peoples Republic of China
Presented at PICALO 2008

Laser-TIG hybrid welding is a technique which develops very rapidly in recent ten years. There have been a lot of reports about the laser-TIG hybrid welding technique and the quality controlling of the welding beads. However, there seems few reports about how the bead shapes and microstructure have been changed for laser-TIG hybrid welding. In this report, 316L stainless steel was welded by Laser-TIG hybrid welding (LTHW), laser beam welding(LBW) and gas tungsten arc (TIG) welding respectively. A series of comparative experiments were carried out to examine the influences of input power (the power of laser or the arc current multiply the arc voltage) on joint morphology, microstructure and hardness. The results showed that with the same input power of 4.5KW, the morphology and hardness of three welded joints had three different characters. The macrostructure of LBW looks like a nail, and the TIG bead looks like a cup, while the LTHW bead has both characters. Furthermore, the TIG welding joint has the largest heat affect zone, in which the size of grains was evidently biggest, while the hardness of LBW was highestand the grain was refined because of its high temperature gradients. The microstructure, composition and micro hardness of the different welding beads were compared, and the concerned mechanisms were discussed. In the end, the corrosion behavior of the three welding beads were investigated.