Grain refinement in additively manufactured ferritic stainless steel by in situ inoculation using pre-alloyed powder

For ferritic stainless steels, TiN has effectively been used as an inoculant to produce equiaxed grain structures in casting and welding. However, it is not established whether would be effective additive manufacturing. In this study, the effectiveness of a steel processed by laser powder-bed fusion studied. An alloy without Ti fabricated compared designed form high amount early during solidification. The work shows that presence provides general refinement TiN-covered oxide particles are enabling columnar-to-equiaxed transition certain regions meltpool. applied approach pre-alloying powders with inoculant-forming elements offers straightforward route achieving fine, additively manufactured metallic materials. It also how oxygen present process can utilized nucleate inoculating phases.