Yang Liu, Yan-hui Sun, and Hao-tian Wu, Effects of chromium on the microstructure and hot ductility of Nb-microalloyed steel, Int. J. Miner. Metall. Mater., 28(2021), No. 6, pp.1011-1021. https://dx.doi.org/10.1007/s12613-020-2092-2
Cite this article as: Yang Liu, Yan-hui Sun, and Hao-tian Wu, Effects of chromium on the microstructure and hot ductility of Nb-microalloyed steel, Int. J. Miner. Metall. Mater., 28(2021), No. 6, pp.1011-1021. https://dx.doi.org/10.1007/s12613-020-2092-2

Effects of chromium on the microstructure and hot ductility of Nb-microalloyed steel

  • It is well-known that the surface quality of the niobium microalloy profiled billet directly affects the comprehensive mechanical properties of the H-beam. The effects of chromium on the γ/α phase transformation and high-temperature mechanical properties of Nb-microalloyed steel were studied by Gleeble tensile and high-temperature in-situ observation experiments. Results indicated that the starting temperature of the γ→α phase transformation decreases with increasing Cr content. The hot ductility of Nb-microalloyed steel is improved by adding 0.12wt% Cr. Chromium atoms inhibit the diffusion of carbon atoms, which reduces the thickness of grain boundary ferrite. The number fractions of high-angle grain boundaries increase with increasing chromium content. In particular, the proportion is up to 48.7% when the Cr content is 0.12wt%. The high-angle grain boundaries hinder the crack propagation and improve the ductility of Nb-microalloyed steel.
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