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Transition of solidification mode and the as-cast γ grain structure in hyperperitectic carbon steels
Title: | Transition of solidification mode and the as-cast γ grain structure in hyperperitectic carbon steels |
Authors: | Tsuchiya, Shingo Browse this author | Ohno, Munekazu Browse this author →KAKEN DB | Matsuura, Kiyotaka Browse this author →KAKEN DB |
Keywords: | Casting | As-cast austenite grain | Solidification microstructure | EBSD | Phase transition |
Issue Date: | Apr-2012 |
Publisher: | Elsevier |
Journal Title: | Acta Materialia |
Volume: | 60 |
Issue: | 6-7 |
Start Page: | 2927 |
End Page: | 2938 |
Publisher DOI: | 10.1016/j.actamat.2012.01.056 |
Abstract: | Formation processes of as-cast γ grain structures during casting of hyperperitectic carbon steels with 0.15-0.45 mass% carbon concentrations have been studied by means of a rapid unidirectional solidification technique. In steels with 0.15-0.41 mass% carbon concentrations, coarse columnar γ grains (CCG) with a minor axis diameter of 1-3 mm developed along the direction of temperature gradient. In a steel with 0.38 mass% carbon, importantly, columnar γ grains (CG) whose minor axis diameter is less than 500 μm form before the formation of CCG and the grain structure discontinuously changes from CG to CCG. The fraction of CG region increases with increase in the carbon concentration. In the samples with the carbon concentration higher than 0.43 mass%, the as-cast structure consists of CG over almost the entire ingots. Analyses of a relation between γ grain and dendrite structures and their crystallographic orientations indicate that the formation of CG originates from the primary solidification of γ phase instead of δ phase. This is supported by numerical analysis of the dendrite growths. |
Type: | article (author version) |
URI: | http://hdl.handle.net/2115/49358 |
Appears in Collections: | 工学院・工学研究院 (Graduate School of Engineering / Faculty of Engineering) > 雑誌発表論文等 (Peer-reviewed Journal Articles, etc)
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Submitter: 大野 宗一
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