No abstract

Abstract. Established dissimilar metal iron and nickel resistance spot welding nugget formation temperature field mathematical model for the discretization of the finite difference method, using TFRSW numerical analysis software, data processing module based on MATLAB language, study the dissimilar metal welding nugget formation in the process of resistance spot welding, the size of the develop and change. Put forward the dissimilar conductive metal welding process, the heat transfer effect simulation method and the analysis method of contact resistance. Design the corresponding experiment, verify the correctness of the results of numerical simulation, and analysis in dissimilar metal in the resistance spot welding specification for welding quality are studied.Resistance spot welding thermal process directly determine the formation and growth of spot welding nugget and the crystallization process, the final decision molten nuclear shape and size. So spot welding thermal process research has a guiding significance to the actual production process analysis. Spot welding nugget formation thermal process mathematical modelThe establishment of the model Spot welding system discretization as shown in figure 1, a total of 1301 nodes, each node are numbered. Fig.1 Discretization model of spot welding system Due to the different area of the spot welding system electrical, thermal, mechanical and performance parameters, such as change is uneven, so using non-uniform grid. Electrode and the workpiece welding area and the area around the grid is populated, and then in turn become sparse.This model features below [1] : At the same time, considering the whole system voltage field and temperature field and the coupling effect. Resistance heat is a major cause of welding nugget melting, boundary expand. Material coefficient of thermal physical properties with temperature changes in calculated value according to the temperature distribution to each step of the way. Consider the workpiece and the electrode surface by convection and radiation to surrounding heat loss. Dissimilar materials welding numerical simulation include dissimilar materials thermal physical properties of the nonlinear and boundary nonlinear problem. Solving process and the result is affected International Forum on Energy, Environment and Sustainable Development (IFEESD 2016)