STUDIES ON THE EXTRUSION

Abstract

It is described the effect of many various factors, which are die hole form, die angle, bearing length, reduction ratio and follower plate form, ets., on the extrusion pressure of Pb and Sn by direct method, as preliminary study on Al and its alloys.The results obtained are as follows:(1) Although the min, pressure is agree with the G. Sachs results, that the extrusion pressure is proportional to the logarithmic reduction ratio, max. pressure at the beginning of extrusion does not agree accurately.(2) At the constant reduction ratio, max, and min. extrusion pressure in circle die are the largest of all other die hole forms, and the smallest is in triangle die.(3) The largest pressure is determined by the two side ratio in rectangle dies at constant reduction ratio and it is smaller in the case of square or sheet form dies.(4) Die angle which gives the smallest pressure is about 65° and the bearing length increases proportionally the max. and min. pressures which are in parallel.(5) It is remarkably affected by the follower plate form, extrusion velocity, lubricant and temperature as in Fig. 12, 14. 15 and Table. 4.(6) It is thought that the billet length greatly increases the max. pressure, but the min. one is constant from the results of Pb and Sn as in Fig. 16 and 17.