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Vol.38, No.10, 1328 ~ 1336, 2000
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| Title |
| Formability of Low Carbon TRIP - Aided High Strength Cold Rolled Steel Sheets Containing Tramp Elements |
| 임동빈Dong Bin Im,이창길Chang Gil Lee,송병환Byoung Hwan Song,김성준Sung Joon Kim,박익민Ik Min Park |
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| Abstract |
| The main emphasis of the present study has been placed on understanding the effect of the tramp elements on formability of TRIP-aided cold-rolled steel sheets. Four kinds of 0.15C-1.5Mn-1.5Si-(Cu, Cr and Ni) cold-rolled steel sheets were prepared. These steel sheets were intercritically annealed at 780-790℃, and isothermally treated at 430℃. Tensile tests and limiting dome height(LDH) test were conducted, and the changes of retained austenite volume fractions as a function of tensile strain were measured using X-ray diffraction. The steel sheets containing Cu or Cu+Ni had higher volume fraction and stability of retained austenite, and formability than those of Cr containing steel sheets, due to high strain hardening rate maintained in the high strain region by the strain induced transformation of retained austenite to martensite. On the other hand, the addition of Cr resulted in forming martensite after heat treatment and showed a dual phase stress-strain curve behavior and low formability. |
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