Effect of Hardenability on Quenching Deformation of Steel Cylinder in Carburized Quenching Process

Quenching is used to obtain beneficial properties of steel products, but it often causes quenching deformation. To suppress this problem, it is important to clarify the influence factors and mechanism of the quenching distortion. In this study, for high hardenability steel, the effects of hardenability on quenching deformation were investigated. Carburizing-quenching deformation of cylindrical specimens of three hardenability steels were examined by experiments and simulations. As hardenability became high, the volume and the diameter of the specimen increased due to quenching. However, the change of the length is not monotonic function of the hardenability, and it has a local maximum value. It is deduced that the non-monotonic dependence of the length change on hardenability resulted from a competition between the increase of elongation by bainitic transformation plasticity and the increase of compressive plastic strain and martensitic transformation plasticity according to the improvement of hardenability.