The important role of titanium microalloying in refining austenite grain of heavy-duty H-beam steel during rough rolling produced by a new technology |
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Authors: | Y Wang J Li F Li Z Ge J Xing Na Li G Zhu H Ding Q Chen |
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Affiliation: | 1. Anhui University of Technology, Key Laboratory of Green Fabrication and Surface Technology of Advanced Metal Materials, Ministry of Education, 50 Hudong Road, 243002 MAANSHAN, P. R., CHINA;2. Anhui University of Technology, School of Materials Science and Engineering, Maxiang Road, 243032 MAANSHAN, P. R., CHINA;3. Anhui University of Technology, School of Metallurgy Engineering, Maxiang Road, 243032 MAANSHAN, P. R., CHINA;4. Soochow University, School of Iron and Steel, 8 Jixue Road, 215137 SUZHOU, P. R., CHINA |
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Abstract: | A new technology of austenite grain refinement, fine austenite enhanced ferrite transformation, is proposed for heavy-duty hot-rolled H-beam steels in this work. Titanium microalloying is very important and necessary for the new technology. The effect of titanium on the prior austenite grain size of steels during simulated rough rolling was investigated. The results show that the prior austenite grain sizes of specimens with titanium and niobium elements are much finer than those of specimens with niobium but without titanium deformed at the same parameters. For the alloying composition of studied steels, titanium nitride particle maybe precipitated in specimens with titanium at above 1,200 °C, however, niobium carbide particles can't form in specimens without titanium at above 1,150 °C. The thermodynamically stable titanium nitride particles can impede the grain growth at high temperature for example furnace heating before rough rolling and bring the epitaxial growth of niobium carbide on pre-existing themselves which induces a large number of titanium nitride-niobium carbide composite precipitates. These fine precipitates can pin austenite grain boundaries effectively and ensure austenite grain refinement. |
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Keywords: | Titanium microalloying ferrite transformation austenite grain refinement heavy-duty steel hot-rolled Titan Mikrolegieren Ferritumwandlung Austenitkorn Kornfeinung Hochleistungsstahl Warmwalzen |
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