피스톤 크라운용 단강에 인코넬 718 용접재료로 용접된 용접부의 특성 평가

• Published in: Han-guk haeyang gonghak hoeji (Online) Vol. 30; no. 4; pp. 334 - 340
• Main Authors: 이성열(Sung-Yul Lee), 문경만(Kyung-Man Moon), 정재현(Jae-Hyun Jeong), 이명훈(Myeong-Hoon Lee), 백태실(Tae-Sil Baek)
• Format: Journal Article
• Language: Korean
• Published: 한국해양공학회 2016
• Subjects: 해양공학; Repair Repair welding 보수 용접; Inconel 718 filler metal inconel 718 용접봉; Corrosion resistance 내식성; Piston crown 피스톤 크라운; Deposited metal 용착금속; Built-up welding 덧살붙임 용접; Weld metal 용접금속; 718
• ISSN: 1225-0767; 2287-6715

The combustion chamber of a diesel engine is often exposed to a more serious wear and corrosion environment than other parts of the engine because its temperature increases as a result of using heavy oil of low quality. Therefore, repair and built-up welding methods must be performed on worn or corroded parts of the piston crown, exhaust valve, etc. from an economical point of view. In this study, Inconel 718 filler metal was used in repair welding on the groove of a forged steel specimen for a piston crown, along with built-up welding on the surface of another forged steel specimen. Then, the corrosion characteristics of the weld metal zone for the repair welding and the deposited metal zone for the built-up welding were investigated using electrochemical methods in a 35% H2SO4 solution. The deposited metal zone indicated better corrosion resistance than the weld metal zone, showing a nobler corrosion potential, higher impedance, and smaller corrosion current density. It is considered that metal elements with good corrosion resistance were generally included in the filler metal, and these elements were also greatly involved in the deposited meta by built-up welding, whereas the weld metal consisted of metal elements mixed with both the filler metal and base metal elements because of the molten pool produced by the repair welding. Finally, it is considered that the hardness of the weld metal was increased by the repair welding, whereas the built-up welding improved the corrosion resistance of the deposited metal.