The Effect of Process Variables on Extrusion Pressures of Lead

Billets of commercially pure lead, 2 in. diam × 3 in. long were extruded at room temperature through five different die contours at ram speeds up to 50 ipm. It was found that, for the direct and indirect extrusions, with good lubrication (white lead in oil) and with good cylinder-wall finish, the extrusion pressure-displacement diagrams were essentially the same. The concentric and eccentric single-bar and multibar extrusions at constant extrusion ratio required approximately the same pressures when extruded at identical speeds. The extrusion pressures over the wide range of speeds investigated showed approximate linearity when plotted on log-log co-ordinates.