Experimental and Numerical Investigation on Laser Welding of 2205 Duplex Stainless Steel

Abstract

Laser Welding is extensively used in many applications including aerospace, automotive, ship building, electronics, home appliance etc., due to its advantage of very low heat input to the weld, resulting in minimum distortion and the ability to weld heat sensitive materials. In this paper, an experimental investigation on laser welding of 2205 Duplex stainless steel has been carried out using a pulsed Nd: YAG laser source. The objective of the present research is to study the effects of welding speed and other parameters such as laser power and pulse width kept as constant on the quality of the butt weld. The quality of butt joints along with base material have been characterized in terms of microstructure and tensile properties. The effect of the welding speed on laser melt pool geometry i.e. penetration depth and bead width is simulated by anisotropic enhanced thermal conductivity approach and those are compared with experimental results. The study reveals that the weld strength increases with scanning speed up to a certain level, and thereafter it starts to reduce. It is also observed that the depth of penetration and bead width decreases with the increase in scanning speed. Moreover, all welded samples contains ferrite content is relatively higher and subsequently, austenite content is lower due to higher cooling rate. The Vickers micro hardness tests across the base material and butt joint samples have been carried out. The results show that the microhardness continuously decreasing from the fusion zone to the base material due to changes in metallurgical phase constituents due to higher cooling rate.