Residual stresses are those stresses which remain in solid materials after removing the external load. Residual stresses which are induced by machining processes play important role in determining the service life of the machined components, depending on its magnitude, sign, and direction. This research provides a comprehensive correlation between three turning parameters and the resulting residual stresses formed on the surface of the outer ring of tapered roller needle bearing, made of 100CrMnSi6-4 type steel. The examined parameters were cutting speed, feed and tool nose radius. Radial and axial residual stresses on the surface were measured using sample cutting-free X-ray diffraction method. It is shown that the effect of one processing parameter can even be opposing depending on the other parameters. Thus, the effects of turning parameters on residual stresses must be examined in a comprehensive manner.

During the evaluation of certain hydrocarbon fields, for the petroleum engineering tests, natural rock core samples are needed. If there is a shortage of such samples, preparation and development of artificially consolidated rock samples become necessary. These samples can be made of different compositions and by using different technologies. The used model materials can play a role in the exploitation of petroleum and natural gas, and they can also promote the development, selection or application of secondary or tertiary technologies in conventional and non-conventional reservoirs. The process developed and used by us makes it available to construct these rock samples from different raw materials, under different pressure and temperature conditions and by using different post-treatment methods. In this paper, the changes of petrophysical parameters (porosity, permeability) originating from a CO2-rich environment ensured by a post-treatment (cure) were analyzed. The authors proposed further investigations of additional important parameters – zeta-potential, wettability – which could alter during different preparation methods of artificially consolidated rock samples, and by this, they could also enhance the research of geological storage of CO2 and EOR technologies.