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Gas Tungsten Arc Welding of Copper and Mild Steel

Daniel T, Timotius P, Maziar R

In this paper, copper and mild steel were welded using a gas tungsten arc welding (GTAW) process. To determine the weldablity factor, tests are needed to provide information on mechanical strength, potential defects in structure, and nature of failure. Mechanical testing included transverse tensile tests, micro hardness tests, and bend tests. The results for the transverse tensile test revealed failure occurred at the copper heat affected zone (HAZ) with an ultimate tensile strength of 220MPa. The weld metal produced the highest average hardness value of 173HV. The bend tests revealed small cracks on the surfaces of each bend and the nature of the bend, bent around the copper HAZ. Metallography revealed ferrite (α) and copper (ε) cellular and dendritic shaped microstructure in the weld metal. Post weld heat treatment (PWHT) was attempted to observe if any improvements on strength could be achieved. Tensile and micro hardness tests revealed the copper base metal increased in ductility significantly and in the weld metal slightly increased in ductility