Abstract
A split billet of mild steel, heated to 1170°C, has been partially extruded through a 180° die using glass lubrication and a ram speed of 210 mm/s. The extrusion ratio was 16·5:1. The strain-rate and strain distribution which occurred in the flow zone have been calculated from measurements of the distortion of a grid inscribed on the split surface. A dead-metal zone did not occur: the flow was similar to that predicted by slip-line field theory lor frictionless extrusion through a square die. The extrusion pressure has been calculated by equating the work done by the ram to the energy dissipated by the flow, allowing for the effects of strain rate and temperature on the flow stress of the steel. Excellent agreement with experiment has been found. The work was carried out to support a larger investigation of the hot extrusion of steels undertaken by Hughes and Sellars and Hughes et al
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