Residual Stresses in Machining Operations
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Residual Stresses in Machining Operations Jose Outeiro Arts et Metiers, Campus of Cluny, Cluny, France
Definition By definition, the residual stresses are multiaxial static stresses that exist in an isolated component without any applied external force or moment, and they are in mechanical equilibrium. Residual stresses are the response to the mechanical and structural history of the component during its manufacturing (metal casting, metal forming, machining, heat treatment, etc.) and in service when submitted to external loadings (thermal, mechanical, and chemical). They are caused by the elastic response of the material to the heterogeneous plastic deformation at any scale of the component or structure.
Theory and Applications Introduction The quality of mechanical components depends on large extend on the surface integrity, which is characterized by the mechanical, metallurgical, and chemical states of the machined affected layers (Jawahir et al. 2011). The residual stresses,
together with the hardness, yield stress, tensile strength, etc., characterize the mechanical state of the machined affected layers. The study of machining operations inducing residual stresses is particularly important when critical structural components are machined, especially, if the objective is to reach high reliability levels and long service life. Both magnitude and distribution of the residual stresses in the machined components can be critical for the functional performance and life of components. Residual stresses can cause a decrease in the static and dynamic strength, a decrease in the corrosion resistance, a dimensional instability (part distortion), changes in the magnetically properties, etc. (Brinksmeier et al. 1982) (see Fig. 1). Therefore, they must be taken into consideration during the design and manufacturing of components. In general, tensile residual stresses at the components superficial layers are unwanted, since they can induce premature fatigue and corrosion failures. On the contrary, the compressive residual stresses at the components superficial layers are beneficial, since they increase the fatigue and corrosion resistances. Residual stress distribution in the machined components results from the machining history but also from the previous materials processing. The machining history consists of a sequence of machining operations (turning, milling, drilling, etc.) and corresponding machining parameters. In
# CIRP 2018 The International Academy for Production Engineering et al. (eds.), CIRP Encyclopedia of Production Engineering, https://doi.org/10.1007/978-3-642-35950-7_16811-1
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Residual Stresses in Machining Operations
Residual Stresses in Machining Operations, Fig. 1 Effects of the residual stresses (Outeiro 2002)
this sequence, the effect of successive machining passes should be also considered (Guo and Liu 2002). Defining a logical machining sequence for a given component, the resulting residual stress distribution in the machined surface layers will depend on the machining parameters used in each ope
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