Finite Element Analysis of the Formation Mechanism of Electrode Pitting in Resistance Spot Welding of an Aluminum Alloy

A finite element analysis was conducted to study the roles of temperature and pressure in the formation of electrode pitting in resistance spot welding of an aluminum alloy. The distributions of pressure and temperature were computed at the electrode tip surface. Results showed that the highest temperature is always located at the center of electrode tip surface, while electrode pressure is concentrated mainly at the edge of contact region. The location of the concentrated electrode pressure coincides with that of electrode pitting, which indicates that the pressure concentration plays a more significant role than the temperature in the formation of pitting.