Abstract
Due to the largely inhomogeneous deformation among constituent phases, the advanced high-strength multi-phase steels are always facing challenges when applied to automotive parts where local formability is critically required. In this work, two characteristic microstructures were produced from a low carbon Ti-V microalloyed steel by varying the cooling path. In the ferrite single-phase microstructure resulted from “ultra-fast cooling (UFC) + furnace-cooling (FC)”, the hole-expanding ratio of 200% and tensile strength of 647 MPa were achieved. In the ferrite-bainite-martensite (F+B+M) multi-phase microstructure produced by “UFC + air-cooling (AC) + UFC”, the ferrite has been strengthened by Ti-V carbides to promote the strain partitioning, which resulted in the tensile strength of ≥780MPa, a moderate elongation and hole-expanding ratio of 93%. The strengthening contributions of Ti-V carbides were calculated to be 126MPa and 149MPa in the ferrite single-phase and F+B+M multi-phase microstructure, respectively.
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Funded by the National Natural Science Foundation of China (51204048) and the Fundamental Research Funds for the Central Universities (N150704006)
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Pei, X., Liu, Z., Wei, J. et al. Microstructure and Properties of a Low Carbon Ti-V Microalloyed Steel. J. Wuhan Univ. Technol.-Mat. Sci. Edit. 33, 1491–1495 (2018). https://doi.org/10.1007/s11595-018-1996-4
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DOI: https://doi.org/10.1007/s11595-018-1996-4