电极表面侵蚀对不等厚异种铝合金点焊形核的影响研究OA

This paper made research on spot welding nucleation of 5mm thick 2219 aluminum alloy and 2mm thick 5A06 aluminum alloy under electrode erosion in the case of multiple consecutive spot weld.And this spot welding process is com-monly used for the Long March 7.Finite element simulation and process experiments were conducted to analyze the effect of electrode erosion on spot welding nucleation of heterogeneous aluminum alloys with different thickness.After excluding external factors such as unstable power output of the equipment,poor cooling effect of the equipment,and inappropriate spot welding process parameters,the analysis results indicate that the diameter of the electrode end face increases because of electrode erosion,and the contact area between the electrode and the specimen increases,this leads to the welding current density decreases and heat generation reduces.And The result is that the more severe the wear on the electrode surface,the higher the content of copper aluminum compounds,and the poorer the conductivity.After the surface condition of the elec-trode deteriorates,the electrode end face forms copper aluminum compounds,and the conductivity decreases,these can eas-ily lead to insufficient or impossible nucleation during the spot welding process.The finite element simulation analysis re-sults indicate that severe deformation of the end face curvature after electrode erosion can lead to a significant decrease in current density in the fusion zone.This causes insufficient heat generation,and inability to nucleate.The spot welding tests were conducted again after the working end face of the flat electrode was ground into a spherical surface.The test welding points had no quality problems of detachment.The correctness of spot welding nucleation analysis under electrode erosion was verified through spot welding nucleation tests after grinding the faulty electrode.