New friction law for the modelling of continuous drive friction welding: Applications to 1045 steel welds

This paper presents the results of a combined experimental and numerical study of continuous drive friction welding of 1045 steel. A new friction law is proposed for the estimation of the apparent coefficient of friction during direct drive friction welding. The temperature distributions are empirically and numerically predicted in the heat affected zone that is formed during the direct drive friction welding of 1045 steel to 1045 steel. Microstructures of the heat-affected zone are presented along with microhardness profiles for the similar and dissimilar welds. Temperature measurements were made at different locations using thermocouples. A finite element model was used to determine the appropriate coefficient of friction to fit the experimental data. A multiparameter regression analysis was then performed to determine the functional dependence of the friction coefficient on process parameters such as temperature, pressure, and sliding velocity. Predictions of the coefficient of friction were in close agreement with the experimental results obtained from the direct drive friction welding trials on 1045 steel. The current results suggest that the new friction law may be used to determine the effects of friction welding parameters on friction coefficients in other material systems.