Hammer Peening is the process of cold working metal surfaces to induce compressive residual stresses to improve its material properties by mechanical means such using hammers. Again this is an alternative to shot peening or roller burnishing and provides the deepest case hardness of all three processes. It however can only be used on area where the surface finish is not so critical, otherwise a secondary machining process is required to improve the surface area.

SBOEVN has special pneumatic hammer peening heads that are employed on the large lathes and deep hole boring machines to provide cold working in the ID of various non magnetic collar components.