| 304 stainless steel has smooth surface,strong corrosion resistance,non-magnetic and other characteristics.It is widely used in industrial production.When using traditional arc welding technology to weld sheet stainless steel,the weld forming is bad and the deformation is serious.In this paper,the resistance welding technology of sheet stainless steel sandwich is studied by means of simulation and experiments,so as to optimize the welding technology and improve the quality of the resistance welding of sheet stainless steel.By this way,we can solve the problem of unattractive surface forming of sheet stainless steel after welding and realize no paint and no grinding after welding.In this paper,1mm 304 stainless steel was taken as the research object,firstly,the temperature field of 304 stainless steel sandwich resistance spot welding was simulated by MSC.Marc simulation software,and the change rule of welding temperature field was obtained.The results show that the cold air flow in the weld center is slow,and the heat dissipation rate is slower than other parts of the base material.The temperature is highest.When the highest temperature is 1568 ?,gradually decreases towards both ends.The welding temperature field is symmetrical distributed with the symmetry axis of the weld center in both transverse and longitudinal directions.However,because the longitudinal point is close to the weld center,the temperature change tends to be stable.The time distribution of temperature at different moments in each part from large to small is : 100ms?130ms?160ms?70ms?50ms?20ms.Secondly,according to the previous experiments and simulation results,the sandwich resistance spot welding process of 304 stainless steel sheet was carried out the influence of welding current,welding time,welding pressure and foil composition on welding quality was studied by adding foil interlayer auxiliary resistance welding mode.At the same time,the response surface method was used for date collection and statistical analysis to obtain the influence of current,time and pressure on the tensile shear strength.The conclusion is that excellent strength performance can be obtained by the interaction of parameters when t he welding current is 20 k A?25k A,welding time is 77ms?130ms and welding pressure is0.13 MPa ? 0.22 MPa for 1mm thickness sheet 304 stainless steel foil solder resistance welding.When the welding current is 22.5k A,the welding time is 101 ms and the welding pressure is 0.16 MPa,the tensile strength of the joint is higher than that of the base material.In the range of better welding process parameters obtained by the test,welding current has the greatest influence on mechanical properties and appearance quality of joint,while welding time has the least effect.On the whole,304 stainless steel sheet sandwich resistance spot welding weldment has no deformation and the appearance of welded joint is smooth and flat without discoloration after welding,but the base metal is polluted due to the melting of the foil interlayer,and even blackened in the severe cases,in addition,because of rough edge and other problems,the workload of post welding treatment is increased. |
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