Effect of magnesium addition in low-carbon steel part 1: behaviour of austenite grain growth |
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Authors: | Xiaobing Li Yi Min Chengjun Liu Maofa Jiang |
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Affiliation: | Key Laboratory for Ecological Metallurgy of Multimetallic Mineral (Ministry of Education), School of Materials and Metallurgy, Northeastern University, Shenyang, P.R. China |
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Abstract: | To reveal the effect of Mg addition on the austenite grain growth in low-carbon steel, the steels containing different Mg contents were refined with a vacuum induction furnace. First, the steels were subjected to the temperature range of 1000–1300°C for a holding time of 30?min. Moreover, using a confocal scanning laser microscope, the growth of austenite grains was investigated under isothermal holding conditions (1400°C), and the γ–α phase transformation was also identified after the samples were subjected to a cooling rate of 5°C?s?1. It reveals that the grain growth is inhibited by Mg addition after increasing the temperature to 1300°C. The kinetic equations of austenite grain growth were further established by regression analysis based on the experimental results. Furthermore, a significant increase in the proportion of intra-granular ferrite takes place in 0.0026%Mg-added steel at the initial stage of γ?→?α with a cooling rate of 5°C?s?1. This is mainly attributed to the plenty of Mg-containing inclusions, which are demonstrated to be effective nuclei for acicular ferrite, being in the Mg-added steel. |
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Keywords: | Low-carbon steel magnesium austenite confocal scanning laser microscope intra-granular ferrite |
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