STUDIES ON THE EXTRUSION (5TH REPORT)

In this report, it is described the effect of mandrel size on extrusion pressure for pipe making of Pb and Sn, various properties of pure Al pipe, and the doudle pipe making by direct extrusion.By studing these problems mentioned above, the results obtained are as follows:(1) When the pipe is extruded by the same form die and the different mandrel in dia., max. or min. extrusion pressure is proportional to A1/A2.If by the same mandrel in dia. and the different die in form, it is proportional to the logarithmic A1/A2.(2) Hardness of pure Al pipe is higher in outerside and is mild at inerside. And it is ununi form at the head of pipe.(3) Double pipe extrusion pressure vs. stroke curves resemble to one of pure metal bar extrusion.And it is uniform in thickness ratio of double pipe at high temperature extrusion.