An austenitic stainless steel AISI 304 and a low-carbon steel 1018 were laser welded in the vertical-up position to form a dissimilar metal joint, by varying the laser beam alignment, gap between the base metals, and filler metal (AISI 309).
The welds were inspected visually and by optical microscopy, and composition profiles were measured using electron probe microanalysis.
It was found that the laser welding produces a fairly inhomogeneous structure in the weld. This is revealed by both the microstructure and the composition profile. The average dilution was found to vary as a systematic function of laser beam alignment. Undesirable levels of dilution were identified as well as ranges of dilution which would provide acceptable weld metal properties.