2011 Volume 29 Issue 3 Pages 234-240
In order to elucidate welding distortion and residual stress generated by laser-arc hybrid welding for high strength steel (HT780), a series of experiments and analyses were carried out. A bead-on-plate welding was carried out by using a fiber laser and CO2 MAG arc welding. For simulating the laser-arc hybrid welding by thermal elastic-plastic analysis, a method for heat input was proposed by considering the penetration shape by laser and arc separately. With using this model and the idealized mechanical properties by considering the phase transformation in cooling stage, welding distortion and residual stress obtained by the experiment were simulated. Synthetically evaluating the results obtained from the proposed heat input model for laser-arc hybrid welding, it was verified that the experimental result could be accurately simulated by the analysis. Even though the dual heat source was used in welding, it was known that welding distortion and residual stress generated by laser-arc hybrid welding for HT780 and their production mechanisms were basically the same as those by laser beam welding.
