86 Int. J. Microstructure and Materials Properties, Vol. 10, No. 2, 2015 Copyright © 2015 Inderscience Enterprises Ltd. Computer modelling of as-quenched hardness and microstructure composition of steel Božo Smoljan* and Dario Iljkić Faculty of Engineering, Department of Materials Science and Engineering, University of Rijeka, Vukovarska 58, HR-51000 Rijeka, Croatia Fax: 00385 51 651490 Email: smoljan@riteh.hr Email: darioi@riteh.hr *Corresponding author Zvonimir Kolumbić Faculty of Humanities and Social Science, Department of Polytechnics, University of Rijeka, Sveučilišna avenija 4, HR-51000 Rijeka, Croatia Fax: 00385 51 216099 Email: zvonimir@ffri.hr Abstract: Industry needs to control and to optimise the process parameters of the steel quenching can be accomplished by considering achievement of desired mechanical properties and microstructure distribution. A joined thermo- metallurgical approach is applied to complete the numerical model of phenomena of steel quenching. Because of wide range of applicability and ease of use of finite volume method (FVM), this numerical method was suitable to create integrated computer program for simulation of transient temperature field, microstructure transformations and mechanical properties during a quenching of steel components. The computer model of steel quenching has been applied for simulation of quenching of steel die components of complex form. By experimental verification of the computer simulation results, it has been found out that phenomena of steel quenching could be successfully described by the proposed computer model. Keywords: steel; quenching; computer modelling; microstructure; mechanical properties; die component. Reference to this paper should be made as follows: Smoljan, B., Iljkić, D. and Kolumbić, Z. (2015) ‘Computer modelling of as-quenched hardness and microstructure composition of steel’, Int. J. Microstructure and Materials Properties, Vol. 10, No. 2, pp.86–100. Biographical notes: Božo Smoljan received his BS and MS from the Faculty of Engineering, University of Rijeka, Croatia and his PhD from the Faculty of Mechanical Engineering of the Belgrade University, Serbia. Currently, he is Full Professor and Head of Department of Materials Science and Engineering at the Faculty of Engineering of the University of Rijeka, Croatia.