Microstructure and properties of rotating magnetic field-assisted laser welded 304 stainless steel joints

This study introduces an innovative magnetic eddy current-assisted laser welding approach to enhance the integrated performance of laser-welded 304 stainless steel joints. Experimental findings reveal that magnetically driven eddy current stirring effectively modulates molten pool temperature gradients, suppresses columnar grain coarsening, and induces significant grain refinement, from 260.12 μm 2 to 143.73 μm 2 , while notably increasing the fractions of high-angle grain boundaries (HAGBs) and ∑3 twin boundaries, reaching 87.31 % and 44.90 % respectively. Moreover, centrifugal effects from rotating magnetic fields enable uniform elemental distribution within the molten pool. Compared to conventional laser welding, the resultant joints fabricated via magnetic eddy current-assisted laser welding show substantial enhancements in both mechanical properties and intergranular corrosion (IGC) resistance, the tensile strength of the joints reached 725 MPa, and the elongation reached 92.12 % of the base material.