Austenite Grain Growth Kinetics after Isothermal Deformation in Microalloyed Steels with Varying Nb Concentrations
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- Annan Kofi Ahomkah
- Department of Materials Science and Metallurgical Engineering, University of Pretoria
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- Siyasiya Charles Witness
- Department of Materials Science and Metallurgical Engineering, University of Pretoria
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- Stumpf Waldo Edmund
- Department of Materials Science and Metallurgical Engineering, University of Pretoria
Description
<p>Grain growth equation constants n, Q and A for Nb bearing steels with the Nb varying from 0.002 wt% to 0.1 wt%, were experimentally determined under reheating and high temperature hot rolling roughing conditions. The constants from these treatments were then used to develop constitutive equations that incorporate the initial grain size Do and a Nb-effect for grain growth predictions in these steels. Comparative analysis of the results showed that the values of the constants generated under rough rolling deformation conditions were slightly higher than those generated under reheating conditions. The activation energy for grain boundary migration Q was found to be in the range of 256 to 572 kJ/mol, the exponential constant n ranged from 2.6 to 6.5 and the material and processing condition’s constant A was found to range from 5.23 × 1011 to 4.96 × 1028 in all cases as a function of the Nb content. Analysis of the influence of the initial grain size Do showed that any contribution of Do can be neglected unless it is equal or more than 70 percent of the average size of the measured austenite grain size D. A logical degree of precision in predicting austenite grain growth in microalloyed steels with different Nb contents, has been achieved in the current work.</p>
Journal
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- ISIJ International
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ISIJ International 58 (2), 333-339, 2018
The Iron and Steel Institute of Japan
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Keywords
Details 詳細情報について
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- CRID
- 1390001206488232320
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- NII Article ID
- 130006362640
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- ISSN
- 13475460
- 09151559
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- Text Lang
- en
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- Data Source
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- JaLC
- Crossref
- CiNii Articles
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- Abstract License Flag
- Disallowed