Surface and Corrosion Properties of Electrolytic Polished 316L Stainless Steel by Double Melting (VIM and VAR)

• Published in: 한국주조공학회지, 43(5) pp. 223 - 229
• Main Authors: 이현승, 김강산, 한승호, 공만식, 윤중열, 장시영
• Format: Journal Article
• Language: English
• Published: 한국주조공학회 01.10.2023
• Subjects: 금속공학
• ISSN: 1598-706X; 2288-8381

In this study, STS316L produced by a double- melting process involving vacuum induction melting (VIM) and vacuum arc remelting (VAR) was subjected to extrusion and drawing to form a tube and was subsequently electrolytic polished (EP). The grain size of the obtained STS316L without EP was approximately 55 µm, with no difference found after EP. The thickness of the EP layer was measured by AES and TEM, showing values of approximately 10 nm and 15 nm, respectively. After EP, the Cr/ Fe and CrO/FeO ratios of the passive layer increased from 1.48 to 1.62 and from 2.15 to 2.26, respectively, while the surface roughness decreased significantly from 0.255 to 0.024 µm. Consequently, the corrosion rate decreased in both NaCl and HCl solutions after the EP process. Additionally, the amounts of eluted Cr and Fe ions were reduced from 1.2 to 0.8 ppb and 10.3 to 0.8 ppb, respectively. Furthermore, polarization tests revealed that STS316L treated with EP required a lower current density to reach a passive state, indicating that corrosion behavior was retarded. KCI Citation Count: 0