Evaluation of Corrosion Property of Welding Zone of Stainless Steel by Laser Welding

doi:2012.26.4.64

J. Ocean Eng. Technol. > Volume 26(4); 2012 > Article

J. Ocean Eng. Technol. 2012;26(4):64-69.
DOI: https://doi.org/10.5574/KSOE.2012.26.4.064

Moon Kyung-Man,Won Jong-Pil,Park Dong-Hyun,Kim Yun-Hae,Lee Myung-Hoon,Kim Jin-Gyeong

Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering Korea Maritime University,Department of Marine Equipment Engineering K

Laser 용접한 스테인리스강의 용접부위의 부식특성에 관한 평가

문경만,원종필,박동현,김윤해,이명훈,김진경

한국해양대학교 공과대학 조선기자재 공학부,한국해양대학교 공과대학 조선기자재 공학부,한국해양대학교 공과대학 조선기자재 공학부,한국해양대학교 공과대학 조선기자재 공학부,한국해양대학교 해사대학 기관시스탬공학부,한국해양수산연수원 교육연구처

Keywords: Laser welding, Intergranular corrosion, Weld metal, Heat affected zone, Corrosion current density, Chromium depletion

핵심용어: 레이저용접, 입계부식, 용접금속, 열영향부, 부식전류밀도, 크롬결핍

Abstract

Laser welding was carried out on austenitic 304 (STS 304) and 22 APU stainless steels. In this case, the differences between the corrosion characteristics of the welding zones of the two stainless steels were investigated using electrochemical methods. The Vickers hardness values of the weld metal (WM) zones in both cases, the STS 304 and 22 APU stainless steels, showed relatively higher values than those of other welding zones. The corrosion current densities of the heat affected zone (HAZ) of the 22 APU and the base metal (BM) zone of the STS 304 exhibited the highest values compared to the other welding zones. It is generally accepted that when STS 304 stainless steel is welded using a general welding method, intergranular corrosion is often observed at the grain boundary because of its chromium depletion area. However, when laser welding was performed on both the STS 304 and 22 APU stainless steels, no intergranular corrosion was observed at any of the welding zones. Consequently, it is considered that the intergranular corrosion of stainless steel can be controlled with the application of laser welding.