In the rail vehicle industry

resistance spot welding is mainly used to weld stainless steel carbody structure whose thickness is less than 5 mm. However

in the stainless steel body structure

the thickness of the bottom frame side beam and the reinforcing beam plate are both 6 mm. It is of practical significance if resistance spot welding can be used to reduce the welding distortion. Double sided single point resistance spot welding for SUS301 L-DLT stainless steel of 6 mm is carried out. The resistance spot welding process is determined through appearance test

smoothness test

section test and tensile shear test. The results show that under the reasonable parameter conditions

the nugget diameter of SUS301 L-DLT stainless steel of 6 mm can reach to φ12.2 mm

and the results of tensile shear test meet standard requirements. The increasing of electrode pressure can effectively avoid the appearance of shrinkage defects.However

the electrode pressure should not be too large

otherwise it may easily cause indentation too deep and nugget diameter too short.