Online ISSN : 1347-5320
Print ISSN : 1345-9678
ISSN-L : 1345-9678
Austenite Grain Coarsening Under the Influence of Niobium Carbonitrides
David San MartínFrancisca G. CaballeroCarlos CapdevilaCarlos García de Andrés
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2004 Volume 45 Issue 9 Pages 2797-2804


This work investigates grain growth behaviour under the influence of pinning carbonitrides in a niobium microalloyed steel. The effect of temperature and heating rate on the grain size is studied. The grain coarsening temperature is determined as a function of the heating rate. It is found that unpinning by precipitates occurs around 40—70 K below the temperature of complete dissolution of carbonitrides. It has been found that experimental results are best described assuming a random distribution of carbonitrides in the matrix and niobium volume diffusion as the rate controlling process for the coarsening of precipitates. Austenite grain growth is explained theoretically taking as a basis the model proposed by Zener, which has been adapted for non-equilibrium kinetics, taking into account the experimental evidence that during a continuous heating, the amount of microalloyed element in solid solution is altered and different from that predicted by the solubility product.

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© 2004 The Japan Institute of Metals and Materials
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