Stainless Steel (SS) demonstrates remarkable overall mechanical properties and corrosion resistance, rendering it highly applicable in critical sectors such as in chemical processing equipment, aerospace components, and medical devices. Additive manufacturing offers a significant avenue for efficient metal part production, bimetallic structures, and functionally graded materials. It is worth exploring new techniques that can fabricate bimetallic structures and functional graded materials of medium-large format parts made of metals.

Layered stainless steel samples were manufactured using plasma Wire Arc Additive Manufacturing (WAAM) technology with optimized process parameters for a Computer Numerical Control welding machine. A multi-material was fabricated by depositing alternating beads of two dissimilar stainless steels on to an AISI 316L substrate. The selected materials were M430 ferritic and M316L austenitic stainless steels. Comprehensive microstructural characterization in different areas, including interfaces between the two different materials, was achieved through optical metallography and electron backscatter diffraction. Results revealed good weldability among the two steels and on the substrate. Also, a gradient duplex structure was observed mainly at the interfaces, suggesting nuanced blending of austenitic and ferritic properties in the welding zone. To establish a direct correlation with mechanical properties in the observed structures, hardness tests were conducted in similar zones. The macro and microhardness tests evidenced the presence of a harder phase along the weld zone. The microstructural analysis corroborated the presence of those mixed phases in conjunction with some delta ferrite areas and a martensitic structure.