Simulation of thin metal deformation by laser welding

Abstract

It is said that the laser welding can weld with low distortion. However, there is few data of numerical value of the deformation in laser welding. For a highly accurate welding with sheet metal by the laser, thermal deformation is very important factor and it is necessary to understand the distortion caused by thermal processing. At first, bead-on-plate by the moving heat source with continuous wave oscillations on the thin metal plate was done.The bead-on-plate where it assumed that the gap not exist in the butt welding means the ideal state in the butt joint. It considers the criterion to understand the deformation by the thermal stress of laser heat source. In the first stage of this study, the welding model was assumed as a bead-on-plate, and calculated it in an ideal state of butt welding without gap. By using these experimental data, the amount of the deformation were measured and calculated. At the same time, the calculation by computer simulation was done to confirm the experimental results. However, there is a gap in the actual welding by all means. Therefore, it is necessary to consider the gap for a calculation. The correct method of calculation is not yet established now. A new computational method was established to clarify these, and the influence of the gap on the welding deformation was examined when an actual butt welding was done. In the butt welding with a gap, the focal positions and energy distributions to the surface of material and joint surface in the butt weld are relating respectively.Deformation in the butt welding included not only thermal stress, but also thermal expansion of melting zone of metal. As a result, using the simulation a welding phenomenon and various behavior of the deformation that happened by laser butt welding was clarified. A new computational calculation method was tried in the present study to clarify these.It is said that the laser welding can weld with low distortion. However, there is few data of numerical value of the deformation in laser welding. For a highly accurate welding with sheet metal by the laser, thermal deformation is very important factor and it is necessary to understand the distortion caused by thermal processing. At first, bead-on-plate by the moving heat source with continuous wave oscillations on the thin metal plate was done.The bead-on-plate where it assumed that the gap not exist in the butt welding means the ideal state in the butt joint. It considers the criterion to understand the deformation by the thermal stress of laser heat source. In the first stage of this study, the welding model was assumed as a bead-on-plate, and calculated it in an ideal state of butt welding without gap. By using these experimental data, the amount of the deformation were measured and calculated. At the same time, the calculation by computer simulation was done to confirm the experimental results. Howev...