고망간 경량철강 냉연판재의 미세조직, 인장특성 및 파괴거동에 미치는 어닐링 온도의 영향 |
이재현1,2, 박성준2, 문준오2, 강전연2, 박준영2, 이태호2, 조경목1 |
1부산대학교 재료공학부 2한국기계연구원 부설 재료연구소 철강재료연구실 |
Effect of Annealing Temperature on the Microstructure, Tensile Properties, and Fracture Behavior of Cold-Rolled High-Mn Light-Weight Steels |
Jae-hyun Lee1,2, Seong-Jun Park2, Joonoh Moon2, Jun-Yun Kang2, Jun-Young Park2, Tae-Ho Lee2, Kyung Mox Cho1 |
1Department of Materials Science and Engineering, Pusan National University, Busan 46241, Republic of Korea 2Ferrous Alloy Department, Korea Institute of Materials Science, Changwon 51508, Republic of Korea |
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Received: 21 October 2016; Accepted: 21 November 2016. Published online: 9 May 2017. |
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ABSTRACT |
The effects of the annealing temperature on the microstructure and tensile properties of cold-rolled light-weight steels are investigated using two Fe-30Mn-xAl-0.9C alloys that contain different Al content. The initial alloy microstructure is composed of a single austenite or a mixture of austenite and ferrite depending on the nominal aluminum content. For the alloy with 9 wt% Al content, the recrystallization and grain growth of austenite occurrs depending on the annealing temperature. However, for the alloy with 11 wt% Al content, the β-Mn phase is observed after annealing for 10 min at 550~800 ℃. The β-Mn transformation kinetics is the fastest at 700 ℃. The formation of the β-Mn phase has a detrimental effect on the ductility, and this leads to significant decreases in the total elongation. The same alloy also forms κ-carbide and DO3 ordering at 550~900 ℃. The investigated alloys exhibit a fully recrystallized microstructure after annealing at 900 ℃ for 10 min, which results in a high total elongation of 25~55% with a high tensile strength of 900~1170 MPa. |
Keywords:
low-density steel, annealing, microstructure, beta-manganese, tensile properties, cold-rolling |
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