Abstract
Right circular phosphor-bronze cones, both annealed and work-hardened, of included angles 30°, 45°, 60°, 90°; 120°, 150° and 170°, have been plastically deformed against a hard flat and the deformation pressure estimated from in situ measurements of the deformed flats. Sub-surface strain hardening has also been studied by measuring the Vickers' hardness at different positions below the flats. It has been found that the deformation pressure of the work-hardened cones increases linearly with the cone angle, while for the annealed cones it decreases as the cone angle is increased. The hardness of the deformed cones revealed that for the annealed cones a plug of strain-hardened material is formed just below the flat. No such plug has been found for the work-hardened cones. It is suggested that the deformation mode controls the variation of the deformation pressure with the cone angle. For the work-hardened cones the deformation mode is qualitatively similar to the predictions of the plasticity theory, whereas for the annealed cones the differences are quite marked.