Residual strain and hardness as predictors of the fatigue ranking of steel welds

This work has investigated the potential of information contained in the microhardness and residual transverse strain profiles just below the weld toe and at mid-depth in the plate, to predict the fatigue performance ranking for a series of 12 MIG welds made in RQT701 steel under different conditions. The experimental matrix included two plate thicknesses, two heat inputs and three types of filler metal. Results have demonstrated that there is significant potential to predict the fatigue performance of welds using parameters that characterise the residual strain/stress and hardness/mechanical property profiles across the weld zone. This type of information would allow a more analytical interpretation to be developed of process–property–performance relationships than has been possible in the past and would assist in process optimisation for service performance under dynamic loading.