The results of an experimental study that analyzed how anisotropic tool topography influences friction and metal flow under warm and hot working conditions are presented. Six sets of H-13 steel platens having different roughnesses were used to compress AA 6061-T6, AA 2024-T4, and AISI 1018 specimens. The platens were machined to have a unidirectional lay while the specimens were prepared to have a constant roughness with an isotropic surface texture. Rectangular specimens were placed at different angular orientations relative to the surface lay of the graphite-lubricated platens and then side-pressed at die temperatures ranging from 149–204°C (300–400°F). Ring tests were also performed in order to determine interface shear friction factors for each experimental condition. Results showed that surface roughness had little effect on planar metal flow whereas specimen orientation showed a strong correlation. An explanation for this behavior is presented based on evidence gathered with a laser measuring microscope. While further investigation is needed, the results indicate that an oriented surface texture has the potential to be used as a tool to optimize flow patterns in bulk forming processes.

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