Numerical Simulation And Technology Of Single-sided Resistance Spot Welding Parameter Optimization Research

Resistance welding is a form of welded joints with stable quality,high production efficiency,easy to realize mechanization and automatic connection methods.It is widely used in automotive,aerospace,electronics,household appliances and other fields.Due to the short welding process time,it is difficult to directly observe the formation of nuggets,therefore,it is necessary to carry out numerical simulation on the process of resistance spot welding in order to obtain the most suitable process parameters for resistance spot welding.In this paper,a numerical simulation of Q235 single-sided resistance spot welding is performed,the pressure distribution under different preloads during the preload phase was obtained.And the different welding time,welding current,temperature field distribution and welding nugget formation in the welding process.It can be obtained through the finite element simulation analysis in the preloading stage,at the end of pre-compression,the forces on the electrode and the workpiece are axial compressive stresses,the axial compressive stress in the welding area is the largest.As the distance from the welding area becomes longer,the axial compressive stress gradually decreases.During the preloading process,both the electrode and the workpiece undergo elastoplastic deformation.The area where the electrode undergoes the largest elastoplastic deformation is inside the electrode,and the area where the workpiece undergoes the greatest elastoplastic deformation is at the contact portion of the welding zone.After the simulation of the preloading phase is finished,the coupling simulation of the spot welding process is performed according to the contact situation obtained at the end of the preloading phase,when performing the electro-thermal coupling simulation,a layer of solid elements is added between the contact surfaces as the contact resistance.The obtained temperature field is applied as a load to the thermo-mechanical coupling model and the final result is obtained.The numerical simulation of the spot welding electric heating process is completed.The numerical simulation of the spot welding process under different process parameters can obtain the distribution of the temperature field during the welding process under different welding currents,welding time,and electrode pressure,thesimulation is verified by welding experiments and metallographic experiments.The results show that the effect of welding current and welding time on the spot welding process is similar and has a large impact.When it is too large,it will cause splashing or deep surface indentation.When the electrode pressure is too small,due to insufficient plastic deformation range and degree of deformation,it will cause spattering,which will cause the nugget diameter to be smaller.When the electrode pressure is too large,it will cause deeper indentation.Therefore,in the actual welding process,it is necessary to select appropriate welding process parameters.