Evaluation of Corrosion Resistance and Weldability of Dissimilar Joint Between Duplex Stainless Steel SAF 2205 and Austenitic Stainless Steel AISI 316L Welded by GTAW Process Using Welding Wires with Codes ER 347 and ER 309L

In this study, the influence of gas tungsten arc welding (GTAW) on microstructure, strength and corrosion resistance of dissimilar weld joint between stainless steel SAF 2205 and stainless steel AISI 316L was investigated. Welding was accomplished by two different types of welding wires with codes ER 347 and ER 309L at the same conditions. To verify soundness of produced welded samples, nondestructive tests including visual inspection, liquid penetrant and radiography were performed. Metallographic samples were prepared from cross-section areas of weld joints to study microstructure of different regions of weld joints by optical microscopy and scanning electron microscopy. The strength of weld joints was determined by tensile tests. Corrosion resistance of weld joints was evaluated by electrochemical polarization and electrochemical impedance tests. In the weld metal which was produced by welding wire with code ER 347, the brittle sigma phase was created resulted in decreasing corrosion resistance of weld joint. According to the results of metallurgical investigations and corrosion tests, it was founded that for produced weld joints, welding wire with code ER 309L causing more strength and more corrosion resistance than welding wire with code ER 347.