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What is Shot Peening and How Does it Work?


Shot peening is a cold working process used to impart residual compressive stresses on to the surface of a component, which results in modified mechanical properties. Shot peening works by striking a surface with a shot (round metallic, glass or ceramic particle) with enough force to generate plastic deformation. When a group of shots impact the surface they generate multiple indentations, resulting in the component being encased by a compressive stressed layer.

The main benefit of shot peening is that the induced compressive stress layer helps to resist the development and propagation of cracks and increases resistance to fatigue failure, corrosion fatigue, stress corrosion and cavitation erosion. Mitigation of these items help extend the service life of a component.

Shot Peening Diagram

What is the Difference Between Shot Blasting and Shot Peening?

Shot blasting is an industrial process used to modify a component’s surface. The process works on the principle of abrasion. A stream of abrasive particles are propelled under high pressure on to the surface of a component to smooth a rough surface, roughen a smooth surface, shape a surface or remove surface contaminants. Shot blasting is often used to prepare a surface for subsequent operations, such as painting of welding.

Shot peening, as previously described, differs from shot blasting in that it is used to improve surface material properties through the addition of compressive stresses.

Shot Peening Applications

Shot peening is used across a wide range of industries to improve the surface properties of components, including medical, aerospace and automotive. Example components include [1]:

  • Gear Parts
  • Camshafts
  • Springs
  • Connecting rods
  • Crankshafts
  • Gearwheels
  • Pistons
  • Drill bits
  • Propeller shafts
  • Compressor blades
  • Turbine blades
  • Landing gear
  • Epidural probes

How can TWI Support?

TWI has a long history of working with its Members, across a range of industry sectors, on improving the performance of materials through additional processing techniques. Please contact us to learn more.


[1] - Shukla, P. P., Swanson, P. T. and Page, C. J. (2014) ‘Laser shock peening and mechanical shot peening processes applicable for the surface treatment of technical grade ceramics: A review’, Proceedings of the Institution of Mechanical Engineers, Part B: Journal of Engineering Manufacture, 228(5), pp. 639–652. doi: 10.1177/0954405413507250.

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