Effect of the consumable on the properties of gas metal arc welded EN 1.4003-type stainless steel: the properties of a modified 12% Cr ferritic stainless steel were evaluated when welded with three different consumables

In this study, modified 12% Cr stainless steel with very low carbon level (0.01%) to improve the weldability and mechanical properties, still conforming to EN 1.4003 and UNS S41003 grades, was joined by gas metal arc welding. Plates 12 mm thick were welded with ER309LSi, ER308LSi, and ER316LSi austenitic stainless steel consumables. Several samples extracted from the joints were subjected to mechanical testing by means of tensile, bend, and Charpy impact toughness tests, while tensile fractographs were examined. Toughness after the postweld heat treatment (PWHT) for 30 min at 720 degrees and 750 degrees C was also examined. Microstructural examinations, including macro- and micrographs, grain size analysis, hardness, and ferrite measurements, were conducted. Salt spray and blister tests for corrosion testing were applied. Considering all data obtained, good strength and satisfactory ductility results were determined, while microstructure-property relationship was explained. It can be recommended to use 309 and 316 welding wires for better corrosion resistance compared to 308 welding wires. More encouraging impact toughness properties related with finer grained microstructure were also obtained for the welds produced by 309 and 316 wires. Postweld heat treatment of the GMA weld with ER308LSi showed good improvement for toughness due to the tempering of the martensite at the coarse-grained heat-affected zone. Increasing heat treatment temperature from 720 degrees to 750 degrees C made additional improvements in toughness