The use of conventional strain gauges evaluation for measurements of residual stresses in welded joints

Abstract

Residual stresses (RS) can reach significant values in a welded joint, committing the quality of the parts since they affect their resistance to fatigue causing cracks and corrosion under stress. The use of strain gauges positioned in specific zones of welded parts, as a way of mapping the RS values from the welding processes, has a great technological interest. The method proposed in this paper defines strategic positions for strain gauges along ASTM A36 steel plates in butt-welded joints using Gas Tungsten Arc Welding. Helped by a signal conditioner, RS values were collected and registered after welding process. The results are the readings of RS imposed by the welding operation, taking into account thermal process effects and the material properties. Experimental results were compared with numerical analysis, via Finite Element Method which showed the potential use of strain gauges for measuring RS from the welding process.