Numerical and semi-analytical solutions of the compound layer growth kinetics in cylindrical surfaces during plasma nitriding of pure iron

E M Hernández,J A Otero,F Castillo,A Jiménez,J E Oseguera,R D Santiago,R Martínez

doi:10.1088/1742-6596/792/1/012056

E M Hernández, J A Otero + Show 5 more

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https://doi.org/10.1088/1742-6596/792/1/012056

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Abstract

Numerical and approximate analytical solutions for the compact layer growth kinetics in a pure iron solid cylinder, during a plasma nitriding process, are obtained. The numerical simulations of the model are performed by using a front tracking finite difference scheme and the heat balance integral method. We propose a model where the main assumption is to consider a diffusion zone of constant thickness, which is solved for cylindrical symmetries. We present results for the time evolution of the compound layer, where the obtained solutions from both methods are consistent with the expected behaviour in the asymptotic time limit and experimental data from other authors.

Highlights

Nitriding thermochemical treatments in different kind of steels are broadly used in industry because of their numerous applications [1, 2]
Plasma assisted thermochemical treatments allow diffusion to occur at low temperatures compared to other processes [1,2,3], so that very low distortions are developed in pieces
Considering mass balance at each interface, we have performed a numerical simulation for the concomitant growth of compact nitride layers during plasma nitriding within a solid cylinder of pure iron

Summary

Introduction

Nitriding thermochemical treatments in different kind of steels are broadly used in industry because of their numerous applications [1, 2]. Plasma assisted thermochemical treatments allow diffusion to occur at low temperatures compared to other processes [1,2,3], so that very low distortions are developed in pieces. Modeling the concomitant growth of compact layers of nitrides in the Fe-N2 thermodynamic system has been targeted by several authors [4,5,6,7]. Considering mass balance at each interface, we have performed a numerical simulation for the concomitant growth of compact nitride layers during plasma nitriding within a solid cylinder of pure iron.

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