The friction and wear behaviour of lubricated ceramic/steel couples was studied, for increasing loads, with a four‐ball tester. For the steel spheres of ceramic/steel couples, a transition point to severe wear was observed, which occurred at loads four to five times higher than the transition for the corresponding steel/steel couple. The extreme‐pressure behaviour for conditions of lubrication with pure hexadecane is compared with the results for lubrication with solutions containing zinc di‐n‐butyl dithiophosphate or zinc di‐sec‐butyl dithiophosphate.
Different tests to determine friction factors for cold forging processes are given in the literature. The double cup extrusion test, the ring compression test and the T-shape compression test are three of the common tests, which are compared in this investigation. From former investigations it is known that there is an influence of the work-hardening of the test sample on the friction factor, which is determined by the test. At this study, the influence of the work-hardening of the material on the three named tests is investigated by using a wire drawing process. In addition, the drawn wire from the originally thermo mechanical rolled wire is also annealed to have a second material state without any work-hardening. The used material and its numerical modelling as well as the analyzed tribological conditions of the real specimens are described. Afterwards the three test setups are explained for the numerical as well as for the real experiments. In the end, the influence of the drawing respectively the work-hardening for the three tests is presented and discussed.
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