Controlled Shot Peening (Cont)

Surface Morphology
Shot peening is the process of impacting materials with spherical media to impart energy to the surface of a component. The amount of stress imparted to the material is proportional to the amount of energy applied; this energy introduces a surface and sub surface compressive layer. The introduction of this compressive layer reduces the effect that any applied tensile stresses may have on the material.

S550H Shot
Surface data
Ra 4.1 µm
Rmax 21.8 µm

S230H Shot
Surface data
Ra 2.7 µm
Rmax 19.0 µm

S110H Shot
Surface data
Ra 1.4 µm
Rmax 8.5 µm

Glass Bead
Surface data
Ra 0.4 µm
Rmax 3.7 µm

 

Surface Tribology
The texture produced by shot peening is often seen as an advantage to component performance in that the dimpled surface can act as a carrier for lubricant which effectively reduces the friction and lowers contact stress. There is a limit as to how coarse this finish can be with respect to performance, each component and individual application requiring careful consideration to develop a technique based on the components in service load case.

Shot Peening Advantages
Increases fatigue life
Increases fatigue strength
Reduces galling
Provides even surface compressive stress layer
Provides consistent and repeatable surface finish
Can work harden surface
Inhibits susceptibility to stress corrosion cracking
Scientifically proven results
Repeatable process

Information for designers and engineers can be found in Design Notes

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