AbstractA mathematical model has been constructed to predict the electrode face diameter at various stages of electrode life. The model relates the electrode face evolution process to electrode design and welding parameters such as welding current, electrode force, etc. It requires a minimum amount of experimental data to determine the numerical constant in the model, which characterises electrode wear rate. To validate the model, constant welding current electrode life test data were used. These data were derived from earlier electrode life tests on six different galvannealed steels. The electrode face diameter was continuously recorded by carbon imprint tests at 200 weld intervals throughout the life tests. Excellent agreement between the experimental results and the model predictions has been achieved. Potential applications of the model in selecting electrode design and optimising welding schedules are also discussed.