PURPOSE: To obtain a seamless extruding hollow stock having extremely less thickness deviation at the initial extrusion time especially by executing a centering upset by filling a hollow billet by pressurizing it inside a container liner after supporting the tip of a mandrel by inserting it into a centering jig.
CONSTITUTION: After setting up the centering jig 5 for supporting the tip of a mandrel 3 at an extruding center at the extruding side of a container liner 1, the tip of the mandrel 3 is supported by inserting it into the centering hole 51 of the jig 5. An extrusion block 6 is then pressurized to the extrusion side by a ram 4, a hollow billet (a) is filled up inside the liner 1 and a centering upset is completed. The jig 5 is then removed from said set up position and after installing an extrusion die 2 at the corresponding position, the ram 4 is pressurized in the extruding direction and the billet (a) is extruded by an ordinary method. In this case, since the state of the mandrel 3 which is maintained more correctly for the extrusion center is attained by the completion of said centering upsetting, the seamless extrusion hollow stock having extreme ly little thickness deviation is obtd. in this extrusion stage.
| WO/2009/067045 | METHOD FOR PRODUCING SEAMLESS LARGE-DIAMETER PIPES |
| JPS5919020 | CONTINUOUS EXTRUDING DEVICE OF STEEL WIRE |
TAKASUGI ATSUMI
KATO KAZUMI
YAMAGUCHI KOICHI
| JPS594206A | 1984-01-11 | |||
| JPS595447U | 1984-01-13 |