LASER IRRADIATED BENDING CHARACTERISTICS OF THE ULTRA-HIGH STRENGTH STEEL SHEETS

Laser forming is an advanced process in sheet metal forming in which a laser heat source is used to shape the metal sheet. This is a new manufacturing technique that forms the metal sheet only by thermal stress. Analyzing the effect of process parameters on the deformation behavior is very important for the application of laser forming process to the real product. In this paper, deformation mechanism and bending behaviors of the ultra-high strength steel sheet SPFC1180Y were investigated numerically and experimentally. Coupled thermo-mechanical FE simulations were firstly conducted to analyze the response related to the bending angle of a square sheet part. The thermo-mechanical behaviors during the straight-line laser irradiated process were presented in terms of temperature, stress and strain. Experiments were then carried out to identify the deformation behaviors with various process parameters such as laser powers, scanning speeds, number of laser irradiations and beam diameters. Results indicate that the bending angle increases with the increase of the laser powers and the absorptivity related to the scanning speeds and number of irradiations. The results also provide a relationship between the bending angle and the line energy imposed on the specimen. The relationship obtained from the paper can be used as a process guide-lines in the laser irradiated bending of SPFC1180Y steel sheets.