Spectroscopic, energetic and metallographic investigations of the laser lap welding of AISI 304 using the response surface methodology

• Published in: Optics and lasers in engineering 2011-07, Vol.49 (7), p.892-898
• Main Authors: Rizzi, Domenico, Sibillano, Teresa, Pietro Calabrese, Paolo, Ancona, Antonio, Mario Lugarà, Pietro
• Format: Article
• Language: English
• Subjects: Austenitic stainless steels; Electron temperature; Laser beam welding; Laser welding; Mathematical models; Optical spectroscopy; Penetration depth; Regression; Response surface methodology; Spectroscopy; Stainless steel
• ISSN: 0143-8166; 1873-0302
• DOI: 10.1016/j.optlaseng.2011.02.014

Spectroscopic signals originated by the laser-induced plasma optical emission have been simultaneously investigated together with energetic and metallographic analyses of CO 2 laser welded stainless steel lap joint, using the Response Surface Methodology. This statistical approach allowed us to study the influence of the laser beam power and the laser welding speed on the following response parameters: plasma plume electron temperature, joint penetration depth and melted area. A clear correlation has been found between all the investigated response parameters. The results have been shown to be consistent with quantitative considerations on the energy supplied to the workpiece as far as the laser power and travel speed were varied. The regression model obtained in this way could be a valuable starting point to develop a closed loop control of the weld penetration depth and the melted area in the investigated process window. ► Laser power is the most influent parameter on all the investigated response variables. ► Higher power or lower speed produce higher keyhole but lower electron temperature. ► A same quantity of energy given by higher speed and power results in deeper keyhole. ► The obtained results could be useful to develop a closed loop control system.