| In this paper,different thickness stainless steel plate is welded by pulsed Nd:YAG laser,the effect of the welding current, pulse width and frequency of the laser welding on deformation,tensile strength and weld morphology is studied,in addition welding parameters is optimized by orthogonal experiment,finally, the welding process temperature field,stress field, angular deformation through finite element ansys software is simulated.Laser welding experiment shows:the welding deformation increases when the welding current (i.e., laser power) adds,pulse width of laser welding impacts the power density and heat input,so it owns the optimum value for a minimum welding deformation;what’s more,there is an optimal value of the laser frequency which can get the smallest welding deformation.The analysis on welding deformation of different thickness steel plate by using orthogonal experiment range analysis method show that:welding current affectes the laser welding deformation most,the pulse width follows, and the laser frequency affects least;with ensuring the premise of weld strength and small welding deformation,the best welding parameters of0.5mm,0.8mm and1mm stainless steel plates welding are confirmed.that is the best welding parameters of0.5mm,0.8mm and lmm stainless steel plates welding is{I, τ, f}, respectively{85A,7ms,3.5Hz},{124A,8ms,3.5Hz},{160A,11ms,3.5Hz}.Ansys, the finite element software, gives a simulation result which indicates the instantaneous temperature field of welding stainless steel with laser is relatively stable, the center of welding heat source has the highest temperature, the temperature gradually decreases with the distance to the center increasing, the profile of isotherm approximate oval, the contour of isotherm is intensive in front of heat welding and the temperature gradient is large, on the other side, the isotherm profile is sparse and the temperature gradient is small; during welding process, the metal in the center of heat source melt and the volume expansion is bound by the lower temperature metal away from the welding heat source, which produce compressive stress, the metal away from the heat center bears tensile stress to balance compressive stress in the center of heat center; during the process of cooling, as the solidification shrinkage of the molten metal, the molten metal is restrained by the neighbour, after cooling, the weld center and adjacent areas will have larger residual tensile stress, while away from the center of the weld generates residual compressive stress; with the power of laser welding increasing, both the welding deformation zone and the angular distortion increases; the thicker the steel plate is, the higher laser power that the laser welding requires, the larger both the welding deformation and the angular distortion is. |
