Prediction of Bainite Intervention in Ferrite-Pearlite Forging Steel II. experimental evaluation
A theoretical model for the presence of bainite (B) in ferrite ( ) + pearlite (P) microstructures was validated experimentally for commercial-grade medium-carbon manganese steels. The energies concerning the nucleation and growth of bainitic- were used as the criteria for the B formation during the...
| Autores: | , , , , |
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| Tipo de recurso: | artículo |
| Fecha de publicación: | 2009 |
| País: | España |
| Institución: | Consejo Superior de Investigaciones Científicas (CSIC) |
| Repositorio: | DIGITAL.CSIC. Repositorio Institucional del CSIC |
| OAI Identifier: | oai:digital.csic.es:10261/73902 |
| Acceso en línea: | http://hdl.handle.net/10261/73902 |
| Access Level: | acceso abierto |
| Palabra clave: | phase transformations kinetic modeling medium-carbon manganese steel forging steel Multicomponent thermodynamics proeutectoid ferrite pearlite Bainite |
| Sumario: | A theoretical model for the presence of bainite (B) in ferrite ( ) + pearlite (P) microstructures was validated experimentally for commercial-grade medium-carbon manganese steels. The energies concerning the nucleation and growth of bainitic- were used as the criteria for the B formation during the þ P transformations, which has been first applied to the changing composition of untransformed austenite ( U). Three steels were chosen to study the effect of Mn content on the B fraction at various cooling rates. To account for local variation of austenite grain size (d0), a log-normal distribution was employed. In this model, C enrichment in U proceeds faster in smaller grains, and the shift to P or B transformation occurs in a specific temperature range. Calculations predicted the onset of B at around 603 K, with a fraction that increases with increasing cooling rate. In general, the agreement was good for all steels in terms of both calculated/observed kinetics and final =P=B fractions. Thus, the model provides a practical prediction of the critical cooling rate in order to avoid B in as-forged product |
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