Influence of Operating Parameters on CO_2 Laser Welded Butt Joints of AISI 304 Stainless Steel Thin Sheets

摘要

In this work, experimental studies were carried out to join the thin AISI 304 stainless steel sheets thickness of 1 mm using CO_2 laser. The effect of welding process parameters (i.e. laser power and welding speed) with varying stand-off distance on mechanical properties, temperature distribution and weld induced residual deformation were determined. The microstructures of the fusion zone, heat affected zone, transition zone and base metal were also investigated. The significant effect of welding speed on mechanical properties and weld induced residual deformation was observed. Under laser power of 1500 W, welding speed of 450 mm/min and stand-off distance of 25 mm, maximum tensile strength was achieved about 87.12% of the base metal. Maximum hardness value was obtained in the fusion zone which was about 157.7% of the base material. Fusion zone exhibited the fine equiaxed dendritic structure and grain coarsening was found in heat affected zone. Maximum angular residual deformation (i.e. 0.057°) was observed at laser power of 1500 W, welding speed of 350 mm/min and stand-off distance of 25 mm. It is observed that residual deformation was increased by increasing the laser power and decreasing the welding speed. There was no significant effect of varying stand-off distance on mechanical properties, residual deformation and peak temperature keeping all other parameters constant.