Shot Peening

This process improves the surface stress distribution of the material, increasing the fatigue strength of the processed part.

How does shot peening improve fatigue life?

Shot peening improves the fatigue life of metal components through the following mechanisms:

1. Introduction of compressive residual stresses

During the shot peening process, small spherical particles (metal, glass or ceramic) are projected at high speed onto the surface of the component. This impact plastically deforms the surface, compressing the outer metal layer and generating residual compressive stresses. These compressive residual stresses are essential to counteract the initiation and propagation of fatigue cracks. Fatigue cracks and strengthen the microstructure of the surface.

2. Reduction of surface defects

Shot peening can minimise the impact of micro surface defects by making the surface more uniform and less prone to failure.

3. Inhibition of crack propagation

If a surface fracture is already present, residual compressive stresses reduce the intensity of the stress at the tip, slowing its growth. This phenomenon significantly increases the service life of the component under cyclic stress.

4. Application to Springs and Connecting Rods

In the case of springs and connecting rods, which are subject to very high cyclical loads, shot peening is essential to:

• Prevent fatigue failures;
• Provide greater resistance to vibration and shock;
• Ensure a long operational life, even under intense stress.
  

What are the benefits of shot peening and in which areas is it applied?

The end result is a significant reduction in the risk of premature failure, an extension of component life and improved overall reliability, particularly important in the aerospace, shipbuilding and automotive sectors, where safety is crucial.