抄録
The effect of the die-shape upon the extrusion pressure for aluminium alloys were examined and the following results were obtained. (1) The extrusion pressure did not change by the variation of the shape of die-hole, while the circumference of hole was raised to 1.4 times. (2) Both the dies of which the lead-in has a radius of curvature and the conical die decrease the extrusion pressure in proportion to the increase of the radius of curvature and conicity. (3) The pressure when using a multiple-hole die was larger than that for the single hole die with the same total sectional area. (4) The bearing length of the die gives only very small influence to the initial pressure, but larger influence to the secondary pressure which is caused by the friction effect. The secondary pressure rises to twice the initial pressure, when the bearing length becomes 5.8 times.
