Effects of Carbon Content on the Weldability of B-Containing <TEX>$620^{circ}C$</TEX> Grade High Cr Ferritic Cast Steel for Turbine Casing

J. Ocean Eng. Technol. 2008;22(6):41-45.

Effects of Carbon Content on the Weldability of B-Containing $620^{circ}C$ Grade High Cr Ferritic Cast Steel for Turbine Casing

Seo Won-Chan,Bang Kook-Soo,Chi Byung-Ha

Division of Advanced Materials Science and Engineering PKNU,Division of Advanced Materials Science and Engineering PKNU,R&D Center Doosan Heavy Industries & Construction Co. Ltd

B 첨가 $620^{circ}C$급 터빈 케이싱용 고Cr 페라이트계 주강의 용접성에 미치는 탄소함량의 영향

서원찬,방국수,지병하

부경대학교 신소재공학부,부경대학교 신소재공학부,두산중공업(주) 기술연구원

Keywords: Weldability, HAZ softening, High Cr ferritic cast steel

핵심용어: 용접성, 열영향부 연화, 고크롬 페라이트 주강

Abstract

Effectsof carbon content on the weldability of B-containing 620 grade high Cr ferritic cast steels were investigated. Cast steel with lower carbon content of 0.07% showed lower HAZ hardness because of the formation of lower carbon martensite in HAZ. It also showed less solidification cracking susceptibility in weld metal because of the formation of delta ferrite. However, hot ductility showed no difference between cast steels with lower and higher carbon contents. Cast steel with lower carbon content showed greater HAZ softening after PWHT in the region heated between AC1 and AC3 because of its higher base metal hardness.