Surface Properties of Electrolytic Polished Layer on STS316L by Single Melting and Double Melting

Abstract

In this study, STS316L produced by a single-melting vacuum oxygen decarburization (VOD) process, referred to as SM, and a double-melting process involving vacuum induction melting (VIM) and vacuum arc remelting (VAR), referred to as DM, was subjected to extrusion and drawing to form a tube, followed by electrolytic polishing (EP). The surface roughness of layer on the DMed sample is 0.02 μm, which is much lower than that on the SMed sample of 0.13 μm. The thickness of the EP layer on STS316L by SM and DM revealed the values of approximately 7.1 nm and 8.2 nm, respectively. The Cr/Fe and CrO/FeO ratios in the EP layer on the DMed sample were 1.62 and 2.26, respectively, while, in the SMed sample, 1.22 and 2.03. Consequently, the EPed STS316L by DM showed better corrosion resistance in HCl solution and small amounts of Cr and Fe eluted in HCl solutions.