Assessment of the joint configuration and welding parameters for the dissimilar joining of AISI 304 L and AISI 410S stainless steels by friction stir welding

The FSW process parameters for dissimilar welding of AISI 410S and 304L stainless steels were meticulously varied to achieve a combination of excellent surface finish, zero voids, and complete tool penetration. These crucial findings have far-reaching practical implications, providing valuable guidance for the welding industry to attain optimal results. In-depth preliminary tests were conducted to determine the precise positioning of the steels between the advancing and retreating sides. During welding, axial forces ranging from 25 to 40 kN were rigorously applied while maintaining a constant rotational speed of 450 rpm and welding speed of 1 mm/s. Considering the welded steels' distinct physical and chemical properties, positioning AISI 410S ferritic stainless steel on the advancing side resulted in a noticeable reduction in flash production and void formation in the stir zone. It was observed that as the axial force increased, there was a proportional rise in flash production, particularly accentuated on the advancing side compared to the retreating side. Nonetheless, this increase in axial force led to a reduction in material insertion size, effectively eliminating flaws at the joints' roots. The research demonstrates the feasibility of producing dissimilar joints between AISI 410S and 304L stainless steels via the FSW process, yielding exceptional surface finish and defect-free stir zones."