Title: Validating the modelling of a gas-jet quenched carburised gear

Authors: Paul Stratton

Addresses: The Linde Group, Rother Valley Way, Holbrook, Sheffield S20 3RP, UK

Abstract: The extensive Computational Fluid Dynamics (CFD) modelling of cooling using nitrogen jets showed that an optimised array of high-velocity gas jets close to its surface could cool the part at a speed similar to that of oil. When these optimised conditions were applied to an idealised gear form, the model suggested that it could be fully hardened if a nitrogen/hydrogen mixture was used. Physical experiments under exactly the same conditions were carried out to try and validate the model. Unfortunately, although close to the physical results, the model results had some important differences. When the model was modified to correct radiation and dynamic-specific heat effects, there was a closer, but by no means perfect, agreement. The finite-element model used at this stage was thought to model heat transfer accurately, but not steel. Therefore, the heat transfer data were applied to a metallurgical model. The results from this model were superior in some respects, particularly regarding the occurrence of phase changes, although it is – again – not perfect.

Keywords: gas quenching; nitrogen jets; modelling; microstructure; carburised gears; computational fluid dynamics; CFD; cooling; finite element method; FEM; heat transfer; phase changes.

DOI: 10.1504/IJMMP.2009.028630

International Journal of Microstructure and Materials Properties, 2009 Vol.4 No.2, pp.156 - 167

Published online: 21 Sep 2009 *

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