Effect of material properties and mechanical tensioning load on residual stress formation in GTA 304-A36 dissimilar weld

Abstract

Using a finite element analysis (FEA) model, the residual stress (RS) formation in an autogenous GTA dissimilar weld between austenitic stainless steel (304) and low carbon steel (A36) are analyzed. The effect of material properties on RS formation was determined by first considering a similar weld of 304 plates, and then changing only a selected mechanical property of the 304 plate on one side of weld to that corresponding to an A36 plate. Enforcing one set of mechanical property to be different at a time helped to isolate the role of these individual properties on the RS formation in the dissimilar weld. The effect of mechanical tensioning on dissimilar welds is then investigated. Results show that the longitudinal RS in both the similar and dissimilar welds can be reduced in the weld zone (WZ) by an amount equal to the stress corresponding to the applied mechanical tensioning load, as the tensioning load is removed after cooling. The mechanism of RS formation in dissimilar weld, and its mitigation by mechanical tensioning are determined by comparing the longitudinal stress evolution on a cross-section of the dissimilar weld plates under the mechanically tensioned and free conditions.