Modeling And Simulating Of Laser Welding For Stainless Steel 304

High power laser welding has been widely used in the industry due to its high productivity and excellent weld quality. The interaction between target material and the high power laser beam is a complex,multi-dimensional, and multi-parameter system. When the power densities are greater than or equal to the order 106/cm2 the target materials are typically used in deep penetration welding, the irradiated surface is molten and subsequently vaporized to form a cavity known as keyhole filled with the laser-induced plasma. This system is characterized by regions with different physical processes, such as phases changing, fluid flowing and solidification. Simultaneous occurrence of melting, vaporization, solidification is the heart of the laser beam welding process. All of these phenomena influence the absorb and reflection of the laser. Up to now there is lack of a suitable mathematic model that might be meet the general laser weld process. An experimental design scheme by using stainless steel 304 was carried out by the method of secondary general rotary regression in this article firstly. Then a high confidence regression equation which uses power, velocity and defocus magnitude as parameters was achieved by analyzing the experiment data with statistic methods. The regularity between the parameters and the shape of welding line was revealed by correlation analysis. Subsequently, with the MATLAB optimization toolbox, an optimized model was created and the best value of every parameter could be calculated to obtain the biggest penetration depth when the penetration width is fixed.Finally, the temperature field of laser welding based on stainless steel 304 was dynamically simulated with the FEA software－ANSYS. In view of the characters of laser welding, a heat source combined the body loads was designed. Considering the high non-linear of the solution and the small focal diameter, a serial of measures were adopted, such as modeling with pyramid, stepped loading and solution. During the load history, an over-measure control method was taken to ensure the precision of nodal selection. It was shown that the simulation results of weld shape were in accordance with the experimental results.