316L 스테인리스강에서 마르텐사이트 생성거동에 미치는 가공열처리의 영향 |
김종식1, 김재남2, 강창룡1 |
1부경대학교 금속공학과 2포항공과대학교 철강대학원 |
Effect of Thermo-mechanical Treatment on the Formation Behavior of Martensite in 316L Stainless Steel |
Jong-Sig Kim1, Jae-Nam Kim2, Chang-Yong Kang1 |
1Department of Metallurgical Engineering, Pukyong National University, Busan 48547, Republic of Korea 2Graduate Institute of Ferrous Technology, POSTECH, Pohang 37673, Republic of Korea |
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Received: 20 December 2017; Accepted: 13 February 2018. Published online: 5 April 2018. |
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ABSTRACT |
This study was carried out to investigate the effect of thermo-mechanical treatment on the formation behavior of martensite in 316L stainless steel. Dislocation, α' and ε-martensite were formed by thermo-mechanical treatment. Martensite with surface relief and specific direction was formed by thermo-mechanical treatment. Martensite formed by thermo-mechanical treatment were reversed to austenite with an ultra-fine grain size of less than 1 μm by annealing treatment at 700 oC for 20 min. α -martensite with a K-S orientation relationship and ε-martensite with a [110]γ || [100]ε orientation relationship to the matrix was formed by thermo-mechanical treatment. The volume fraction of dislocation, α' and ε-martensite were increased with the cycle number of thermo-mechanical treatment. In 5-cycle number thermo-mechanical treated specimens, more than 25% of the volume fraction of α -martensite and less than 5% of the volume fraction of ε-martensite were attained. The austenite grains were fairly deformed by thermo-mechanical treatment and the grain size of austenite with various orientation relationship were changed from micrometer to sub-micrometer by the 5-cycle thermo-mechanical treatment. |
Keywords:
thermo-mechanical treatment, 316L stainless steel, α -martensite, ε-martensite, TEM, EBSD |
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