Microstructure and corrosion behavior of friction-surfaced 304L austenitic stainless steels

Abstract

Friction surfacing is a solid-state deposition process that provides microstructural and mechanical property benefits over fusion-based deposition methods as a result of the lower heat input and hot working. The study examines microstructure and corrosion properties for friction-surfaced 304L stainless steel consumable rods on 304L stainless steel substrates. Microstructural characterization revealed fine-grained microstructure with distributed strain-induced martensite and high residual compressive stresses. Corrosion studies of friction-surfaced specimens were carried out by exposure to FeCl3 and MgCl2 solutions per ASTM G48 and ASTM G36 standards, respectively. The corrosion tests showed friction surfacing led to shallower and smaller pits than the uncoated substrate, however, the pit number density was higher in the friction-surfaced specimens. The microstructural transformations during friction surfacing are beneficial to mitigating pitting corrosion and potentially chloride-induced stress corrosion cracking (CISCC).