A 4.3-in-diam cylindrical commercially pure lead billet was extruded at room temperature into a 1.5-in-diam solid bar at three extrusion rates of 0.1, 0.74, and 5.15 ipm. Particle velocities, magnitude, and direction, for the inverted extrusion process using a sharp-edged die, were determined on a meridian plane by a stepwise extrusion method. It was found that for the extrusion rates investigated the flow pattern was invariable with respect to the extrusion rates. Measured wall pressures were found to increase approximately linearly with the extrusion speed in a similar manner as the extrusion load, such that the ratio of applied pressure to the wall pressure remained constant. Theoretical considerations appear to agree with the experimental observations. The mean pressure within the metal differed from the measured wall pressure by the condition necessary to establish plastic flow. The predicted mean pressure obtained from a graphical analysis of the velocity pattern of the billet agreed approximately with the measured mean pressure.

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