1972 年 21 巻 224 号 p. 424-427
Measurement was made of the pressure below which the steady state rate of extrusion is negligibly slow, and above which it grows with steep slope against increasing extruding pressure, i. e. extrusion pressure, as the function of entrance angle α of cone shaped dies. The extrusion pressure increases with increasing α. This tendency, which can not be explained with the equation of the preceding paper, was analyzed according to the method of the slip line analysis. Several slip line fields were obtained with high frictional coefficient of μ=0.2 and of degree of processing as high as possible. The stress fields around the exit of the dies affect the extrusion pressure.
The profile of the longitudinal section, wide at entrance and narrow at exit, is presumed to be suitable for smooth extrusion.