Mechanical shock is sometimes used to stabilize tool steels. One method of producing shock is to suspend the part so that it hangs freely and then strike it with a wooden hammer. This is believed to set up elastic waves which add to the magnitude of the residual stress imparted by the previous heat treatment. At locations where the resultant magnitude of stress exceeds the elastic limit, plastic flow should occur and result in stress relief. This would be manifest by higher dimensional stability. A shock treatment should not be considered as a substitute for a thermal method of stabilization but rather as an auxiliary method which enhances stabilization.
Dimensional changes in W1 steel resulting from dropping on a concrete floor as determined by Fletcher (are shown in Fig. 6. The untempered specimens showed greater dimensional changes than the tempered specimens due to the higher level of residual stress in the untempered condition.
For more information, click on the link below (subscription required). Then scroll to Figure 6.
Jon L. Dossett; George E. Totten, *Control of Distortion in Tool Steels*, ASM International, 2014
https://doi.org/10.31399/asm.hb.v04d.9781627081689
