RESIDUAL STRESSES IN GROUND AND IN PEENED SURFACE

Residual stresses have long been of great concern to manufacturing and design engineers, due to their major effect on the service life of most enginee ring components and structures. These stresses are induced by finishing processes, and they can be either benef icial t o the life of me tal components whe n they a re compre ssive, or detrime ntal when in tens ion. This work looks at the residual stress distribution introduced by grinding, and compares it to that generated by shot peening. Residual stress determination was carried out using Sachs'method. This method consists of removing layer of material from the surface of tubular specimens . After each layer is removed, the change in strain is measured using a strain gauge mounted on the surface of the specimen's bore if material is removed from the outside surface, or stuck on the outside surface if material is removed from the surface of the bore. To achieve metal removal without creating further residual stresses, electrochemical machining was used. The calculation side of residual stress determination is based on the work of Hanslip on residual stresses in the surface of hardened oil field pump rods. The residual stress profiles drawn were those obtained from specimens with five finishing processes including hardened-only , gentle grinding, severe grinding , gentle grinding followed by shot peening, and severe grinding followed by shot peening. It was found that all of the above processes generated compressive residual stresses at the surface. However, the magnitudes were much higher for the shot-peened specimens . Surface profiling was also used to obtain roughness parameters for the processed surfaces. To illustrate the effect of grinding and of peening on fatigue strength , samples were subjected to rotating bending fatigue tests . These showed that the fatigue resistance of ground specimens and shot-peened ones improved at long life from that of hardened-only specimens by more than 10%.

Grantor dc:publisher

Oxford Brookes University

Author dc:creator

• Abdellioui, Reda

Contributors dc:contributor

• Adlington, John

Statement dc:rights

• All rights reserved

Language dc:language

en

DOI dc:identifier

https://doi.org/10.24384/apky-jm57

OAI identifier oai:identifier

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