The Effect of Aging Treatment on the Microstructure and Mechanical Properties of Super Duplex Stainless Steel with W

J. Ocean Eng. Technol. 2009;23(4):52-57.

Kim Soo-Chun,Bae Dong-Soo,Kang Chang-Yong

Advanced Metallugy Pukyong National University,Advanced Metallugy Dong-ui University,Advanced Metallugy Pukyong National University

W이 첨가된 슈퍼 2상 스테인리스강의 미세조직과 기계적성질에 미치는 시효처리의 영향

김수천,배동수,강창룡

부경대학교 신소재공학과부,동의대학교 신소재공학과,부경대학교 신소재공학과부

Keywords: Super duplex stainless steel, Aging treatment, Sigma phase, Kai phase

핵심용어: 슈퍼2상 스테인리스강, 시효처리, ${sigma}$상, ${chi}$상

Abstract

The effect of aging treatment on the microstructure and mechanical properties of super duplex stainless steel with W was investigated. The phase was precipitated mainly at the early stage of aging and a lower aging temperature under $750^{circ}C$, but the phase was formed after long-term aging treatment between $600^{circ}C$ and $900^{circ}C$. The volume fraction of the phase increased with aging temperature up to $750^{circ}C$ and then decreased up to $900^{circ}C$. With an increase in the aging time, the volume fraction phase at the early stage of aging increased slightly, and then increased rapidly beyond a certain time. The rapid increase in the tensile strength and hardness and decrease in the elongation and impact toughness were measured with aging temperatures up to $750^{circ}C$. On the other hand, the tensile strength and hardness decreased slightly, and the elongation and Charpy impact toughness were unchanged with aging temperatures over $750^{circ}C$. The tensile strength and hardness increased rapidly at the early stage of aging, and then increased slowly beyond a certain time. The elongation and Charpy impact toughness decreased rapidly at the early stage of aging, and then remained unchanged beyond a certain time. The phase that formed at the early stage of aging and the lower aging temperature had a considerable effect on the elongation and Charpy impact toughness of the super duplex stainless steel with W.