An Electrochemical Evaluation of the Corrosion Property on the Welded Zone of Sea Water Pipe according to Welding Materials

J. Ocean Eng. Technol. 2007;21(5):39-46.

Kim Jin-Gyeong,Won Chang-Uk,Jo Hwang-Rae,Lee Myung-Hoon,Kim Yun-Hae,Moon Kyung-Man

Education and Research Division Korea Institute of Maritime and Fisheries Technology,Education and Research Division Korea Institute of Maritime and Fisheries Technology,Dept. of Mechanical and Materials Engineering Korea Maritime Univ.,Dept. of Marine

용접 재료 별 해수 배관 용접부위의 부식 특성에 관한 전기화학적 평가

김진경,원창욱,조황래,이명훈,김윤해,문경만

한국해양수산연수원 교육연구처,한국해양수산연수원 교육연구처,한국해양대학교 공과대학 기계소재 공학부,한국해양대학교 해사대학 기관시스템공학부,한국해양대학교 공과대학 기계소재 공학부,한국해양대학교 공과대학 기계소재 공학부

Keywords: Corrosion potential, Galvanic cell, Welding metal, Heat affected zone, Shielded metal arc welding, Inert gas arc welding

핵심용어: 부식전위, 갈바닉 전지, 용접금속, 열영향부, 금속피복아크용접, 불황성가스 아크용접

Abstract

The sea water pipe of a ship's engine room is a severely corrosive environment caused by fast flawing sea water containing chloride ions and high conductivity. Therefore, leaking of sea water may occur as a result of local corrosion of the welded zone. Leaking is usually controlled by various welding methods. In this study, when the sea water pipe is welded with certain welding methods and welding electrodes, the corrosion resistance of WM (Welding metal) and HAZ (Heat affected zone) was investigated using electrochemical methods. Although the corrosion potential of the HAZ is higher than that of WM, the corrosion resistance of WM is superior to HAZ. However, when WM and HAZ are both opened to the sea water, the WM part with the anode was more seriously corroded than was the HAZ of the cathode by performance of a galvanic cell due to difference of the corrosion potential between HAZ and WM. In particular TIG welding showed relatively good results in corrosion resistance of both HAZ and WM compared to other welding methods.