Weld-bead profile and costs optimisation of the CO2 dissimilar laser welding process of low carbon steel and austenitic steel AISI316

The dissimilar full depth laser-butt welding of low carbon steel and austenitic steel AISI 316 was investigated using CW 1.5 kW CO2 laser. The effect of laser power (1.1–1.43 kW), welding speed (25–75 cm/min) and focal point position (−0.8 to −0.2 mm) on the weld-bead geometry (i.e. weld-bead area, A; upper width, Wu; lower width, Wl and middle width, Wm) and on the operating cost C was investigated using response surface methodology (RSM). The experimental plan was based on Box–Behnken design; linear and quadratic polynomial equations for predicting the weld-bead widthness references were developed. The results indicate that the proposed models predict the responses adequately within the limits of welding parameters being used. The regression equations were used to find optimum welding conditions for the desired geometric criteria.