Control of Residual Stresses Using Narrow Gap Technique in SMA Welding of Structural Steel

Abstract

Welding of structural steel plate having conventional V-Groove and narrow grooves of different designs has been carried out by GTAW ischolar_main pass followed by SMAW filler passes. The residual stresses of the weld and HAZ have been measured by centre drill hole technique using three-element strain gauge rosette. Effect of narrow gap welding of different groove design on residual stresses of weld joint has been studied. The effect of variation in heat input per pass in the SMAW filler passes of the narrow gap welds on residual stresses of the weld joint also has been studied. The residual stresses along with the microstructure and hardness of the conventional and narrow gap weld joints have been compared. It has been observed that the use of narrow gap welding with comparatively low heat input reduces the residual stresses of weld joint significantly compared to that observed in conventional V-Groove weld. This is primarily attributed to reduction in amount of weld deposit lowering the contraction stresses in narrow gap weld.