Cast austenitic stainless steel (CASS) often contains high contents of silicon, phosphorus, and sulfur to prompt low melting phases to form in the welds. As a result, welding defects can be induced to degrade the welds. This study's purpose was to investigate the effects of electromagnetic stirring (EMS) on the CASS weldments. The results showed that the ferrites in the heat affected zone (HAZ) had tortuous grain boundaries, while those that were close to the fusion lines had transformed austenites. EMS could reduce the influence of the welding heat to make the grain boundaries less tortuous and the transformed austenites smaller. Although their temperature profiles were almost the same, the gas-tungsten-arc-welding (GTAW) weld had smaller grains with massive ferrite colonies and more precipitates, while the GTAW+EMS weld had denser ferrite colonies with multi-orientations, but fewer precipitates. The hardness of the base metals and HAZs were typically higher than that of the welds. For both of the welds, the root was the region with the highest hardness. The hardness decreased from the root to the cap regions along the thickness direction. The GTAW weld had a higher hardness than the GTAW+EMS weld. At room temperature, the GTAW+EMS weld had a higher notched tensile strength and elongation than the GTAW weld. This could be attributed to the observation that the GTAW+EMS weld had dense and intersecting dendrites and that more austenites were deformed during tensile testing.

The purpose of this study was to evaluate the temperature fluctuation induced by electromagnetic stirring (EMS) and to investigate the influence of temperature fluctuation on the appearance and microstructure of the stainless steel welds. CF8A and 308L were used for the base metal and weld metal, respectively. Bead-on-plate welding (BOP) was conducted with a linear welding machine of gas tungsten arc welding (GTAW) with EMS. The experimental results show that EMS could prompt temperature alteration rates (TARs) to fluctuate between positive and negative, and enlarge the max/min ratios. Smaller ripples and surface roughness would be induced on the welds, while the dilution and the depth-to-width ratios both decreased. As a result, the ferritic and austenitic grains become more isotropic and their grain sizes become smaller.