Dissimilar Welding between AISI 304 Stainless Steel and AISI 1020 Carbon Steel Plates

This work studied the feasibility of dissimilar welding between AISI 304 stainless steel and AISI 1020 carbon steel plates with the thickness of 15 mm. The processes applied in this work were gas tungsten arc welding (GTAW) and shield metal arc welding (SMAW). Microstructure of weld metal produced by GTAW consists of delta ferrite network in austenite matrix, while the dendrite of delta ferrite finely distributed in austenite matrix was found in the weld produced by SMAW. Hardness values of weld metals produced using these two techniques were superior to those of stainless steel and carbon steel base metals respectively. Weld metals produced by these two processes were qualified under tension and bending. This was justified by the result that the failed part after transverse tensile test was on carbon steel, and no crack was found in weld metal after U-shape bending. Impact test exhibited higher toughness of weld metal produced by GTAW than that produced by SMAW. This might be from microstructure of the former weld as network of delta ferrite in austenite matrix which might help absorb impact energy. Pitting corrosion potential of weld metal produced by GTAW was higher than that produced by SMAW and stainless steel base metal respectively. In the aspect of mechanical and corrosion properties of the weld, GTAW was considered as a promising process that could be used for dissimilar welding between these two metals.