Induction heat treatment of a ISO C45 steel bar: Experimental and numerical analysis I. Magnabosco * , P. Ferro, A. Tiziani, F. Bonollo Department of Management and Engineering, DTG University of Padova, Stradella S. Nicola 3, Vicenza 36100, Italy Received 17 May 2004; received in revised form 16 March 2005; accepted 17 March 2005 Abstract An experimental and numerical study of the induction heat treatment applied to ISO C45 steel was carried out. Both normalised and annealed samples were considered. The process parameters were implemented in a numerical code (Sysweld 2000 Ò ) with an aim of predicting the thermal and metallurgical history of the material. The aim of this work was to create a thermo-metallurgical model of the induction heat treatment validated by experimental results. The experimental results (microstructure and micro-hardness profiles) were compared to the numerical values. A satisfactory agreement was found. Ó 2005 Elsevier B.V. All rights reserved. Keywords: Induction heating; Quenching; Heat treatment; ISO C45 steel; Modelling; Finite element analysis; Metallurgical transformations 1. Introduction The development of numerical codes to calculate thermal histories, phase transformations and stress fields of different materials allow us to develop models which can predict the effects of heat treatment on the metallur- gical and mechanical properties of machine compo- nents. It is very useful to forecast distortions, residual stresses, phase distributions, hardened depth, thickness of carburized layer, etc. Therefore, the possibility of optimising the process parameters by using numerical simulations rather than experimental tests, could be- come very advantageous both in design and economic aspects. In literature it is possible to find many works regarding the quenching heat treatment with very encouraging results [1–3]. However, numerical models of more complex heat treatment, as the induction heat- ing and quenching, are still in progress. It is clear that the complexity of the phenomena involved in a generic heat treatment, such as heat exchange, elements diffu- sion, phase transformations and the consequent Ôtrans- formation plasticityÕ [4–6], makes the analysis very heavy. Furthermore, it is necessary to take into account the non-linearity of the material laws, functions of tem- perature and phases. So, the need to experimentally validate these models, and verify their reliability, is still very high. This work describes the numerical and experimental analysis of the induction heat treatment of a C45 steel bar. Experimental data were obtained by hardness tests and optical microscope analysis. The material properties, taken from literature, and the process parameters, were implemented in the numerical code with the aim of deter- mining the thermal and metallurgical history of the material under investigation. The solid–solid phase transformation model, based on the contributions of Leblond and Devaux [7], Johnson-Mehl-Avrami [8–11] and Koistinen-Marburger [12] contribution, was taken into account. A high coupling level was considered 0927-0256/$ - see front matter Ó 2005 Elsevier B.V. All rights reserved. doi:10.1016/j.commatsci.2005.03.010 * Corresponding author. Tel.: +39 444 998754; fax: +39 444 998888. E-mail address: ilenia.magnabosco.@unipd.it (I. Magnabosco). www.elsevier.com/locate/commatsci Computational Materials Science 35 (2006) 98–106