Numerical Simulation Study Of Dissimilar Steel Magnetron Arc And Welding Process Law

There are a large number of different materials of steel welding structural parts in shipbuilding,petrochemical industry,bridge construction and other engineering fields.Compared with the welding of the same kind of steel,the welding of dissimilar steels has better mechanical properties in practical applications,such as corrosion resistance and excellent biocompatibility.At the same time,since the cost of it is lower,it is widely used.However there are great technical difficulties in welding of dissimilar steels.Due to the large differences in the thermophysical properties of the base materials of dissimilar steels,the welding temperature field often presents an uneven distribution,which intensifies the stress and deformation of the welding workpiece itself.The quality of welded joints is poor,so traditional welding methods need to be improved.Considering that the welding heat input is the main reason that directly affects the welded joints,the article proposes to introduce a non-contact external magnetic field to control the arc deflection during the welding of dissimilar steels,and then adjust the energy distribution of the welding heat input in the workpiece,and finally obtain a good dissimilar steel welded joints.Therefore,it is necessary to conduct in-depth exploration on the welding of magnetically controlled dissimilar steels to obtain the basic law of action,so as to provide a certain theoretical basis for the welding of magnetic controlled dissimilar steels.Since the welding process involves a large number of complex physical processes,it is difficult to conduct in-depth analysis and research on it through experiments alone.Therefore,this paper analyzes the welding process of dissimilar steels and combines related theories to establish a two-dimensional simulation software based on COMSOL Multiphysics.Steady state magnetic controlled arc dissimilar steel welding model and three-dimensional transient magnetic controlled dissimilar steel welding model.Calculate the workpiece temperature field of the two models under different welding currents and excitation current intensities,and verify the coupling of the calculation results of the molten pool of the two models.At the same time,the corresponding parameters are tested,and the simulation is compared with the arc in the test results.The shape and welding deformation of the workpiece were verified,which proved the reliability and accuracy of the simulation model.On the basis of the above-built model,the post-welding workpiece deformation and arc temperature field and shape under different welding currents and excitation current strengths are calculated,and compared with the test results,it is found that: 1.Welding The current has no obvious effect on the arc shape,but as the welding current increases,the energy density and temperature gradient inside the arc will also increase,and the heat action area of the arc will become larger;the deformation of the workpiece after welding is positively correlated with the welding current.2.The direction and magnitude of the exciting current play a decisive role in the arc shape and deflection.When the magnitude of the excitation current is the same,the opposite excitation current will make the arc reverse deflection,and the deflection amplitude and direction are almost symmetrical about the weld.When the direction of the excitation current is the same,as the excitation current increases,the degree of arc deflection gradually increases;from the deformation of the workpiece after welding,it can be intuitively seen that the excitation currents of different directions and magnitudes cause different deflection of the arc.The contact surface and heat conduction path between the arc and the workpiece are changed,that is,the welding heat input distribution in the welding process is changed.Therefore,when welding dissimilar steels,according to the material of the workpiece,an external magnetic field should be used to control the arc for proper deflection,and the heat input of the workpiece should be controlled reasonably,so as to obtain better weld quality.