Papers in JOURNAL OF THE JAPAN SOCIETY FOR TECHNOLOGY OF PLASTICITY
(vol.42 no.482 March 2001)
Effects of Entry Porthole Shape on Extrusion Pressure and
Dimensional Accuracy of Extruded Pipes at Hollow Die Extrusion
Toshiyuki INAGAKI, Satoshi MURAKAMI, Norio TAKATSUJl,
Kenji MATSUKI, Mitsuyuki ISOGAI and Jun SYOBO
(Received on July 12, 2000)
The effects of a paper porthole on the extrusion pressure of rectangular extruded pipes are investigated using
the extrusion test. The extrusion pressure of a circular taper porthole is lower than that of a straight porthole, while the extrusion pressure of the radial taper porthole is much lower. Because the areas of plastic
deformation zone in the taper porthole and the welding chamber are increasing, the degree of circularity of the
taper porthole worsens. However it is useful for the improvement of the circularity of the radial taper
porthole with setting a longer mandrel, because the extrusion pressure is low in all porthole shapes tested and
longer mandrels enable more accurate sizing of the inside diameter of a hollow.
Key words : extrusion, extrusion pressure, circularity of rectangular extruded pipes, entry porthole die shape, metal flow
Formability of AZ31 Magnesium Alloy Sheets under Warm Working Conditions
Tetsuro OHWUE, Sho-ichi SEKIGUCHI, Masao KIKUCHI and Satoshi ITOH
(Received on July 4, 2000)
Uniaxial tensile tests and square shell deep drawing tests were carried out to investigate the formability of
AZ31 magnesium alloy sheets under warm working conditions. From 293K (room temperature, RT) to 573K,
tensile strength (TS) decreases and elongation (El) increases with the increase of temperature. Under warm
working conditions, greater than 448K, square shell deep drawability increases with the increase of tempera-
ture, even though square shells cannot be formed at room temperature.
Key words : magnesium, mechanical properties, deep drawability, square shell, warm working condition