슈퍼오스테나이트계 스테인리스강 GTA 용접부의 용접 적층 및 입열에 따른 공식 부식 특성

• Published in: 대한용접·접합학회지 Vol. 38; no. 6; pp. 528 - 534
• Main Authors: 고대환(Dae-Hwan Ko), 박영일(Young-Il. Park), 신용택(Yong-Taek Shin)
• Format: Journal Article
• Language: Korean
• Published: 대한용접·접합학회 01.12.2020; 대한용접접합학회
• Subjects: 기계공학; Heat input; Welding pass; 654SMO; GTA welding; Superaustenitic stainless steel; Critical pitting temperature
• ISSN: 2466-2232; 2466-2100
• DOI: 10.5781/JWJ.2020.38.6.2

This study investigated the corrosion characteristics of weldments on superaustenitic stainless steels for various heat inputs and numbers of welding passes during gas tungsten arc welding(GTAW). The heat input was changed to 0.7 or 1.4 kJ/mm and the weldment microstructure and chemical composition were analyzed. The weldment corro sion resistance was evaluated by potentiodynamic polarization, and the critical pitting temperature (CPT) was determined. The CPT dropped from 85 to 55 ℃ with both increasing heat input and number of welding passes. The microstructural and chemical compositional analyses revealed that the Mo segregated and precipitated in the inter dendritic region, and that the Mo content in the dendritic core was lower than that in the surrounding area. The Mo content decreased when the pitting corrosion initiated. The precipitate content and dendrite core size both increased, and the pitting corrosion resistance decreased with both increasing heat input and number of welding passes. KCI Citation Count: 0