Shot peening

[meemouk]

It is known that shot-peening increases the fatigue strength of a material as it leads to residual compressive stresses in the surface and subsequently increases the resistance to crack initiation and growth. My question is, does shot-peening affect the resistance to static stresses too? or not since it affects only the surface of the specimen?

 

[CoryPad]

It can affect the static strength performance, although your statement regarding near-surface does explain its limited usefulness. Sometimes, the shot peening may not be beneficial for static strength because it is additive to applied stresses with respect to multiaxial yield criteria (e.g. von Mises/octahedral shear/distortion energy).

 

[jamalhad]

jamalhad(Mechanicl,manufacturing)
It is customary to use shot-peening and or shot-blasting as secondary or finishing operation in manufacting parts such as Leaf Springs for suspension system of heavy trucks or trailers. .This finishing operation comes after heat treatments( Right after Oil quenching)in which it improve and relaeses the residual stress.Thin in turn extends the perfomance of stack of leaf springs under operation.See some immages:{

https://www.google.com/search?q=lea...niv&sa=X&ei=XyM3VdWaBs7faujQgagO&ved=0CBwQsAQ

}

 

[tbuelna]

With gears, shot peening is used to create a residual compressive stress in the surface of the tooth root fillets where tensile stresses are highest due to bending forces on the cantilevered tooth structures. Carefully applied shot peening of the root fillet surfaces is very effective at improving the fatigue capability of gear teeth under bending. In fact the improvement in bending fatigue capability provided by shot peening can be quite impressive. But bending fatigue of gear teeth is mostly dynamic loading conditions and high cycles. Most gears are engineered so they will likely fail due to surface contact fatigue (pitting) at the tooth flank long before they fail due to a fatigue fracture in the root fillet surface. And I can't think of many gear applications that are subject to static loads/stresses. Such a gear would likely experience plastic deformation at the flank contact long before any tooth failed in bending.

Attached is a brief description of shot peening as applied to gear teeth.