J. Phys. IV France 112 (2003) 437
DOI: 10.1051/jp4:2003919

A physically based model for the isothermal martensitic transformation in a maraging steel

S.O. Kruijver¹, H.S. Blaauw², J. Beyer³ and J. Post<sup>2

1</sup>  Delft University of Technology, Laboratory of Materials Science, Microstructure Control of Metals, Rotterdamseweg 137, 2628 Delft, The Netherlands
²  University of Twente, Department of Mechanical Engineering, P.O. Box 217, 7500 Enschede, The Netherlands
³  Philips ATC, P.O. Box 20100, 9200 Drachten, The Netherlands

Abstract
Isothermal transformation from austenite to martensite in steel products during or after the production process often show residual stresses which can create unacceptable dimensional changes in the final product. Tn order to gain more insight in the effects infiuencing the isothermai transformation, the overall kinetics in a low Carbon-Nickel maraging steel is investigated. The influence of the austenitizing température, time and quenching rate on the transformation is measured magnetically and yields information about the transformation rate and final amount of transformation. A physically based model describing the nucleation and growth of martensite is used to explain the observed effects. The results show a very good fit of the experimental values and the model description of the transformation, within the limitations of the inhomogeneities (carbides and intermetallics, size and distribution in the material and stress state) and experimental conditions.

© EDP Sciences 2003