The structure and mechanical and corrosion properties of stainless steel obtained by WAAM from a developed flux-cored wire

Wire arc additive manufacturing (WAAM) is an additive technology in which a metal wire is melted with an electric arc, and the parts are formed layer by layer. Austenitic stainless steel wires are promising materials in the manufacture of parts via WAAM. Austenitic steels have good ductility and corrosion resistance, but low strength. Nitrogen alloying, which leads to solid-solution hardening, can increase strength. In addition, austenitic stainless steels are sensitive to the formation of hot cracks during welding, which can be corrected by the low content of δ-ferrite in the structure of such steels.

In this work, a flux-cored wire was developed using WAAM, which ensures the formation of an austenitic–ferritic structure of the deposited metal. The chemical composition of the deposited metal was as follows: wt. %: 0.055 C; 0.43 Si; 5.0 Mn; 20.1 Cr; 4.1 Ni; 2.1 Mo; 2.9 Cu; 0.319 N.

The characteristics of the WAAM product made from developed flux-cored wire were compared with the properties of AISI 321 steel. The deposited layers of the experimental composition were characterized by greater microhardness and improved strength characteristics, with a slight decrease in plastic properties, compared with AISI 321 steel. In addition, the developed material surpasses AISI 321 steel in terms of the pitting potential in artificial seawater. The phase composition of the deposited layers is deformationally stable: no austenite–martensite phase transformation was detected in tensile plastic deformation tests.

This research was carried out with the support of a grant from the Russian Science Foundation (RSF) No. 24-19-20059 (https://rscf.ru/en/project/24-19-20059/) and the Government of the Sverdlovsk Region.