FINITE-ELEMENT ANALYSIS OF ELECTRODE WEAR MECHANISMS - FACE EXTRUSIONAND PITTING EFFECTS

Resistance spot welding is one of the major joining methods widely use d in automotive body fabrication and assembly. Electrode weal has been a major concern in resistance spot welding of galvanised steel and in this paper advanced finite element techniques were used to simulate t he thermomechanical interactions between the electrode and the workpie ce during welding. First, the coupled electric-thermal-mechanical proc ess associated with nugget formation was studied. The cumulative effec ts on electrode face deformation were then simulated over a large numb er of welds. Electrode face pitting effects were also examined. It was found that welding process parameters, such as holding time and press ure trace, played a key role in electrode face extrusion. Any pitting on the electrode tended to accelerate the face extrusion process.