Quench Distortion
H. K. D. H. Bhadeshia
With some steels, it is necessary to rapidly cool a component in order to achieve martensitic transformation and the desired strength and hardness. Rapid cooling is associated with large temperature gradients, which in turn lead to the development of residual stress. The component will distort when the stresses are not uniform. The heterogeneous distribution of the stresses which lead to distortion can be induced either by a nonuniform shape or nonuniform cooling.
The movies below are from experiments conducted by Professor M. Narazaki (Utsunomiya University, Japan) and reproduced with the permission of K. Arimoto for teaching purposes.
There are two movies showing the quenching of a shaft with a keyway parallel to its length. The first movies shows quenching in water and the second in a polymer solution. The latter is associated with more uniform cooling and less distortion. The movies are in MPG format (2 Mb).
