C-Mn계 TRIP강의 잔류오스테나이트 생성과 기계적 성질에 미치는 역변태처리의 영향

유재선; 홍호; 이오연; 진광근; 김성주; J.S. You; H. Hong; O.Y. Lee; K.G. Jin; S.J. Kim

Korean Journal of Materials Research, Vol.14, No.2, 126-132, February, 2004

DOI10.3740/MRSK.2004.14.2.126 Export Citation

C-Mn계 TRIP강의 잔류오스테나이트 생성과 기계적 성질에 미치는 역변태처리의 영향

Effect of Reverse Transformation Treatment on the Formation of Retained Austenite and Mechanical Properties of C-Mn TRIP Steels

유재선, 홍호, 이오연 ^†, 진광근¹, 김성주¹

전북대학교 신소재공학부, 자동차신기술연구센터
¹POSCO 기술연구소 자동차강재연구센터

J.S. You, H. Hong, O.Y. Lee^†, K.G. Jin¹, and S.J. Kim¹

School of Advanced Materials Engineering & AHTRC, Chunbuk National University, Chonju, Chonbuk, Korea
¹Automotive Steels Research Center, POSCO Technical Research Lab., Gwangyang, Jeonnam, Korea

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The high strength steel sheets has been widely used as the automobile parts to reduce the weight of a vehicle. The aim of this research is to develop the TRIP aided high strength low carbon steels using reverse transformation process. The 0.15C-4Mn and 0.15C-6.5Mn steel sheets were reversely transformed by slow heating to intercritical temperature region and air 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 645 ? C for 12 hrs. was about 46vol.% in hot rolled 0.lC-6.5Mn 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 tendency of tensile strength to increase with increasing the holding temperature was due to the decrease of retained austenite after cooling from the higher temperature of 670 ? C . The maximum strength-ductility combination was about 4,250 kg/ mm 2 ㆍ% when the hot rolled 0.lC-6.5Mn steel was reversely transformed at 645 ? C for 12 hrs.

Keywords:TRIP steels;reverse transformation;retained austenite;strength-ductility combination

[References]

Koh HJ, Ph. D. Thesis, POSTECH (1998) (1998)
Hayami S, Frukawa T, Microalloying, 75, 87 (1975)
Matsumura O, Sakuma Y, Takechi H, Trans. Iron and Steel Inst. Japan, 27, 571 (1987)
Chen HC, Era H, Shimizu M, Metall. Trans., 20A, 437 (1989)
Furukawa T, Mater. Sci. Tech., 5, 465 (1989)
Furukawa T, Hwang H, Matsumura O, Mater. Sci. Tech., 10, 964 (1994)
Miller RL, Trans. ASM, 57, 892 (1964)
Miller RL, Trans. ASM, 61, 592 (1968)
Huang H, Matsumura O, Furukwaq T, Mater. Sci. Tech., 10, 621 (1994)
Chen HC, Tomokiyo K, Era H, Shimizu H, J. Iron and Steel Inst., 75, 56 (1989)
Chung JH, Ph. D. Thesis, POSTECH (1993) (1993)
Speich GR, Demarest VA, Miller RL, Metall. Trans., 12A, 1419 (1981)

[Related Articles]

[1] Koh HJ, Ph. D. Thesis, POSTECH (1998) (1998)

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

[3] Matsumura O, Sakuma Y, Takechi H, Trans. Iron and Steel Inst. Japan, 27, 571 (1987)

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

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

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

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

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

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

[10] Chen HC, Tomokiyo K, Era H, Shimizu H, J. Iron and Steel Inst., 75, 56 (1989)

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

[12] Speich GR, Demarest VA, Miller RL, Metall. Trans., 12A, 1419 (1981)