Mechanical surface treatments - Effects on materials

As we have already seen in [M 1 190] , mechanical surface treatments essentially modify three parameters of a mechanical part:

• surface finish through material crushing;

• residual stresses through heterogeneous plastic deformation between the surface and sublayer of the material;

• the microstructural state through work hardening or phase transformation of the treated material.

These changes will therefore influence a range of material properties associated with these parameters, including fatigue, crack initiation and propagation, wear resistance, corrosion resistance and stress corrosion, etc. In subsequent dossiers, we will deal with the beneficial or detrimental role of a treatment in relation to a given stress on a case-by-case basis. In this issue, we only summarize the differences or commonalities between the various treatments.