4~8%Mn 열연 TRIP강의 잔류오스테나이트 생성과 기계적 성질

김동은; 박영구; 이오연; 진광근; 김성주; DE Kim; YK Park; OY Lee; KG Jin; SJ Kim

Korean Journal of Materials Research, Vol.15, No.2, 115-120, February, 2005

DOI10.3740/MRSK.2005.15.2.115 Export Citation

4~8%Mn 열연 TRIP강의 잔류오스테나이트 생성과 기계적 성질

Formation of Retainted Austenite and Mechanical Properties of 4~8%Mn Hot Rolled TRIP Steels

김동은, 박영구 , 이오연 ^†, 진광근¹, 김성주¹

전북대학교 신소재공학부 신소재개발연구센터
¹POSCO 기술연구소 자동차강재연구센터

DE Kim, YK Park , OY Lee^†, KG Jin¹, and SJ Kim¹

School of Advanced Materials Engineering & RCAMD, Chonbuk National University, Chonju, Chonbuk, 561-756, Korea
¹Automotive Steels Research Center, POSCO Technical Research Lab., Gwangyang, Jeonnam, 545-711, KOrea, Korea

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The aim of this research is to develop the TRIP aided high strength low carbon steels using reverse transformation process. The 4\~8% Mn steel sheets were reversely transformed by slow heating to intercritical temperature region and furnace cooling to room temperature. The stability of retained austenite depends on the enrichment of carbon and manganese by diffusion during the reverse transformation. The amount of retained austenite formed after reversely transformed at 625 ? C for 6 hrs was about 50vol.% in the 8%Mn steel. The change in volume fraction of retained austenite with a holding temperature was consistent with the changes in elongation and the strength-ductility combination. The maximum strength-ductility combination of 40,000 MPa?% was obtained when the 8%Mn steel reversely transformed at 625 ? C for 12 hrs. However, it's property was significantly decreased at higher holding temperature of 675 ? C resulting from the decrease of ductility.

Keywords:TRIP steel;retained austenite;reverse transformation;mechanical property

[References]

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Tamura I, Maki T, Hato H, Trans. Iron and Steel Inst. Japan, 10, 163 (1970)
Hayami S, Frukawa T, Microalloying, 75, 87 (1975)
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Huang H, Matsumura O, Furukawa T, Mater. Sci. Tech., 10, 621 (1994)
Chung JH, Ph. D. Thesis, POSTECH, 70 (1993)
Haidernenopoulos GM, Steel Research, 67, 93 (1996)

[Related Articles]

[1] Zackay VF, Parker ER, Fahr D, Bush R, Trans. ASM, 60, 252 (1967)

[2] Tamura I, Maki T, Hato H, Trans. Iron and Steel Inst. Japan, 10, 163 (1970)

[3] Hayami S, Frukawa T, Microalloying, 75, 87 (1975)

[4] Matsumura O, Sakuma Y, Takechi H, Trans. ISIJ, 27, 571 (1987)

[5] Chen HC, Era H, Shimizu M, Metall. Trans., 20A, 437 (1989)

[6] Sakuma Y, Matsumura O, Takechi H, Metall. Trans., 22A, 489 (1991)

[7] Sugimoto K, Kobayashi M, Hashimoto SI, Metall. Trans., 24A, 3085 (1993)

[8] Furukawa T, Mater. Sci. Tech., 5, 465 (1989)

[9] Furukawa T, Hwang H, Matsumura O, Mater. Sci. Tech., 10, 964 (1994)

[10] Miller RL, Trans. ASM, 57, 892 (1964)

[11] Miller RL, Trans. ASM, 61, 592 (1968)

[12] Ruhl RC, Cohen M, Trans. AIME, 245, 241 (1969)

[13] Huang H, Matsumura O, Furukawa T, Mater. Sci. Tech., 10, 621 (1994)

[14] Chung JH, Ph. D. Thesis, POSTECH, 70 (1993)

[15] Haidernenopoulos GM, Steel Research, 67, 93 (1996)