Full Penetration Laser Welding Heat Source Numerical Model And Parameter Research

As an advanced materials processing technology, laser welding is applied more and more widely in manufacturing industry with the advantage of high energy density, deep-penetrating, high-precision and strong adaptability. Laser welding process contains a series of complex physical and chemical reaction phenomena. Its essence is the existence of keyhole and plasma effect. And numerical simulation is an important research method in the field of material processing today.The paper combines laser welding with numerical simulation and simulates laser welding temperature field with finite element analysis software ANSYS. Proceeding from the macroscopic heat transfer process, suitable heat source distribution model is established to reflect the impact of keyhole. Formation of keyhole is not involved. Keyhole impact of heat and force is reflected on appropriate volume heat source distribution model. Through the establishment of three-dimensional transient model to simulate laser welding process, the corresponding temperature field distribution and size of weld seam are got to reflect the actual welding process.By making a test plan, laser welding experiment of three different thickness plates is carried out. The effect of different laser power and welding speed is observed and researched. Weld seam forming regularity is studied by weld morphology statistics. Heat source model parameter sensitivity is discussed when cone-shaped heat source model is selected. Then effect of parameters variation on temperature field simulation results is obtained. According to the results of laser welding experimental, heat source model parameters of three different thickness plates are found with orthogonal experimental principle. Calculation results show that the cone-shaped heat source model can better accord with the experimental results and effectively reflect the actual laser welding process.Conception of the energy required to melt unit volume of material is raised. Under the condition of full penetration welding, the conclusion that the energy required to melt unit volume of material is almost the same is got when size of weld cross section area is derived from the measurements of experiment results. Thus for determined welding power and speed, if melting width in upper surface is known, melting width in down surface can be roughly estimated.Further, when melting width in upper and down surface is known, heat source model parameters can be sought out by inversion method, combining with numerical simulation. Consequently, in a certain welding technology condition, a method is given to determine cone-shaped heat source model parameters and facilitate the simulation and projection of laser welding temperature field.