Microstructure and Impact Toughness of Weld Metal in Multipass Welded Super Duplex Stainless Steel

doi:2012.26.6.27

J. Ocean Eng. Technol. > Volume 26(6); 2012 > Article

J. Ocean Eng. Technol. 2012;26(6):27-32.
DOI: https://doi.org/10.5574/KSOE.2012.26.6.027

Seo Won-Chan,Park Chan,Bang Kook-Soo

Department of Advanced Materials System Engineering Pukyong National University,Department of Materials Science and Engineering Pukyong National University,Department of Advanced Materials System Engineering Pukyong National University

다층용접한 슈퍼 듀플렉스 스테인리스강 용접금속의 조직 및 충격인성

서원찬,박찬,방국수

부경대학교 신소재시스템공학과,부경대학교 재료공학과,부경대학교 신소재시스템공학과

Keywords: Super duplex stainless steel, Weld metal, Toughness, Microstructure

핵심용어: 슈퍼 듀플렉스 스테인리스강, 용접금속, 인성, 미세조직

Abstract

The effects of reheating during welding on the microstructure and impact toughness of weld metal in 25% Cr super duplex stainless steels were investigated. Using different heat inputs, weld metals with different reheated regions were obtained. This showed that, depending on the reheating temperature, the microstructure in the reheated region was quite different from that of the as-deposited microstructure. When reheated into the ${gamma}+{alpha}$ temperature range, fine intragranular austenite was formed in the as-deposited columnar structure. However, when reheated above the ${alpha}$ solvus temperature range, most of the columnar structure disappeared and fine equiaxed austenite and ferrite were formed. Because of the larger amount of fine austenite in the reheated region, a higher impact toughness was obtained in the weld metal with a higher amount of reheated region.