Shot Peening Residual Stresses Cold working causes plastic deformation that creates residual stresses. The degree and sign of the residual stress depend on degree and type of the working process. Shot peening is a cold working process in which the surface of a component is peened with small spherical balls called shots. The process induces plastic deformation on the surface, relieves surface tensile stresses and introduces beneficial compressive residual stresses. Shot peening is a similar process with surface rolling, both deform the surface plastically to develop a compressive residual stress depth profile. STRESSTECH BULLETIN 14 Text: Murat Deveci, Figures: Stresstech The close-up photo shows the difference between shot peened and not peened surfaces. Stress formation during shot peening process. Typical shot peened surface’s stress depth profile. In this example, over 400 MPa of compressive residual stress is induced on the subsurface layers of the component. Through the depth, changes in the stress direction and values are confirmed by X-ray diffraction.
noise signal level consistently increases, in hard martensitic (carburized or surface hardened) materials, Barkhausen noise signal level decreases.
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- Spring '18
- Dr. maarten bakker