14th International Conference on Shot Peening

Evolution of the controlled shot peening process in the automotive field

E. Morgano

SILCO Rivalta TO

Abstract

The controlled shot peening process, on a mechanical component, represents the most robust solution to increase its resistance to fatigue; moreover, since it is usually the last operation in the production chain, it does not change the parameters of the previous operations, such as forging, mechanical processing and surface hardening treatments.

The choice of shot peening parameters and minimum values of residual stresses in compression are essential to keep the operation under control; the optimal residual stress, from surface up to deep, profile depends on the type of damage to be solved.

The next steps of controlled shot peening, using compressed air equipment, concern the optimization to reduce the surface roughness and further improve the resistance to sub-surface fatigue (pitting).

In this regard, there are some solutions ranging from a final super-finishing to a double shot peening, with a second softer operation in terms of intensity, using both steel and ceramic shot.

The further evolution of technology in the automotive field concerns flat products (sheets) for Chassy components; for these applications, the state of the art provides for turbine shot blasting.

Studies are underway for the introduction of a targeted shot peening with compressed air that confers high residual stresses limited to the areas most stressed by the project.

Finally, as regards the final quality checks of the process, X-ray diffractometry that allows you to investigate both the surface and in depth by electrolytic removal, requires constant updating of the reference legislation.