Effects of absorptivity, shielding gas speed, and contact media on sheet metal laser welding

A three-dimensional quasi-steady state heat conduction model is developed f or laser welding of sheet metals. The heat flux at the surface of the workp iece is considered to be due to a moving Gaussian laser beam. An analytical expression is obtained for the temperature distribution by solving the con duction problem using the Fourier integral transform technique. this expres sion is used to locate the melting temperature isotherm, and thereby determ ine the weld depth and width. Experimental and theoretical results for the weld depths and widths are illustrated for different welding parameters suc h as the laser power absorptivity, welding speed, and shielding gas speed. The theory and experiment are found to agree reasonably well. The effects o f absorptivity, shielding gas speed, and heat loss due to different contact media at the bottom surface of the workpiece are also investigated, and ar e found to be significant for thin metal laser welding.