For ledeburitic tool steels (typical 8-12%-Cr cold-work tool steels and high-speed steels) the interaction of carbides with the matrix must be taken into account, especially when these carbides are strongly oriented after plastic deformation (rolling, forging) of the pre-material.
The longitudinal direction of the carbides is usually parallel to this forming direction. Different authors suggest that the orientation of forming is the preferred direction of change in length caused by hardening. For the tool maker it is important to take this behavior into account.
Results from investigations of a ledeburitic cold work tool steel are shown in the graph. The micromechanical interactions between carbides and the matrix cause an inhomogeneous change in length during austenitizing as well as during quenching. Finally, an elongation in the longitudinal direction and a shrinking in the transverse direction remain.
Volume 4D, Heat Treating of Irons and Steels -> Tool Steels -> Distortion in Tool Steels -> Nature and Causes of Distortion
