Extrusion molding method and apparatus of extrusion press

Abstract

An extrusion molding method of an extrusion press includes a first step of loading a billet, the outer surface of which is subjected to a barking treatment, into a container, and extruding the billet in such a manner as to leave a predetermined length, a second step of loading a next billet into the container, additionally extruding the preceding billet with the succeeding billet in such a manner as to leave a predetermined length of the succeeding billet; and a third step of loading a next billet into the container and additionally extruding the preceding billet with the succeeding billet in such a manner as to leave a predetermined discard length of the succeeding billet and stopping extrusion. By way of these steps, the container does not move while maintaining contact with a die, and the billet is continuously extruded by leftover and additional extrusion.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is an explanatory view showing an outline of a suitable apparatus according to an embodiment of the present invention;

FIG. 2 is a flowchart for explaining operation states ((a) to (e)) with the passage of time in the embodiment of the invention;

FIG. 3 is an explanatory view showing an extrusion leftover length in an extrusion stem stop state in first and second steps in the embodiment of the invention;

FIG. 4 is an explanatory view showing an extrusion leftover length in an extrusion stem stop state in a third step in the embodiment of the invention;

FIG. 5 is an explanatory view showing a Comparative Example for the purpose of comparison with an extrusion molding method of an extrusion press according to the embodiment of the invention;

FIG. 6 is an explanatory view showing an outline of an extrusion molding apparatus according to the present invention;

FIG. 7 is an enlarged view of principal portions of FIG. 6;

FIG. 8 is a sectional view taken along line VIII to VIII of FIG. 7; and

FIG. 9 is an explanatory view showing a Comparative Example for the purpose of comparison with an extrusion molding apparatus according to the embodiment of the invention.

Claims

1. An extrusion molding method of an extrusion press including a gas exhausting step of sucking and exhausting air inside a container simultaneously with the start of upset for pushing a billet inside said container by using a billet from which an oxide film on an outer surface and contamination is removed, and comprising: a first step of loading said billet into said container, extruding said billet with the advance of an extrusion stem until a billet extrusion leftover length reaches a predetermined length, and stopping extrusion;a second step of loading a next billet into said container, additionally extruding said preceding billet with said succeeding billet with the advance of said extrusion stem until an extrusion leftover length of said succeeding billet reaches a predetermined length, and stopping extrusion; anda third step of loading a next billet into said container, additionally extruding said preceding billet with said succeeding billet with the advance of said extrusion stem until an extrusion leftover length of said succeeding billet reaches a predetermined discard length, and stopping extrusion;wherein said second step is conducted at least once after completion of said first step and removal of said discard is conducted outside an extrusion molding apparatus after completion of said third step.

2. An extrusion molding method of an extrusion press according to claim 1, wherein the leftover length of said billet is set to a wrap-in length of a surface kin layer before the wrap-in start of a surface skin layer.

3. An extrusion molding method of an extrusion press according to claim 1, wherein in said gas exhausting step, a seal member is pushed to an end face of said container on the side of said extrusion stem and to an outer peripheral surface of said extrusion stem after said billet is loaded into said container, and they are brought into close contact with each other to seal said container, air inside said container is sucked from the side of said extrusion stem simultaneously with the start of upset, and said gas exhausting step is completed after exhaust is carried out to a predetermined degree of vacuum.

4. An extrusion molding method of an extrusion press according to claim 2, wherein in said gas exhausting step, a seal member is pushed to an end face of said container on the side of said extrusion stem and to an outer peripheral surface of said extrusion stem after said billet is loaded into said container, and they are brought into close contact with each other to seal said container, air inside said container is sucked from the side of said extrusion stem simultaneously with the start of upset, and said gas exhausting step is completed after exhaust is carried out to a predetermined degree of vacuum.

5. An extrusion molding method of an extrusion press according to claim 1, wherein the removal of the oxide film and contamination on the outer peripheral surface of said billet is conducted by cutting processing or peeling means such as a scalper before the supply of said billet into said extrusion press or inside said extrusion press machine.

6. An extrusion molding method of an extrusion press according to claim 2, wherein the removal of the oxide film and contamination on the outer peripheral surface of said billet is conducted by cutting processing or peeling means such as a scalper before the supply of said billet into said extrusion press or inside said extrusion press machine.

7. An extrusion molding method of an extrusion press according to claim 3, wherein the removal of the oxide film and contamination on the outer peripheral surface of said billet is conducted by cutting processing or peeling means such as a scalper before the supply of said billet into said extrusion press or inside said extrusion press apparatus.

8. An extrusion molding apparatus equipped with exhaust means for a container having a seal member and seal means for sealing an end face of a container and an outer peripheral surface of an extrusion stem, comprising: a fix dummy block capable of coming into close contact with an inner wall surface of said container and provided on a distal end of said extrusion stem;wherein said fix dummy block has at an axial distal end portion thereof an exhaust valve device including an outer ring the distal end of which can expand in an outer radial direction and a dummy core capable of moving in an axial direction while communicating with an exhaust passage inside said outer ring, and the exhaust passage communicates with said exhaust means.