JPS63154213A - Damage prevention method for ceramics die for indirect extrusion - Google Patents

Abstract

PURPOSE:To reduce a shock force applied to a die body at the time of removing a press residue and prevent damage to the die body by previously applying a mold lubricant to Al billet faces, a face of a die contacting with the billet, and a die ring face. CONSTITUTION:In the case that extrusion of Al stock by an extrusion device, extrusion is performed with a mold lubricant previously applied to faces of the Al billet or faces of an extrusion metal die directly contacting with the billet, that is, the front face of a die 1 and a die ring 4. A dispersion liquid in which graphite is dispersed in a solvent or boron nitride, etc., is used as the lubricant. After an extrusion is completed with the lubricant applied, a joint part between a press residue B and an extruded stock A is cut by a shear to remove the residue B. The lubricant exists between the residue B and a face of the die 1 and a face of the die ring 4, so that the said members are separated by a small force and a required shear force amount is reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a method for preventing damage to ceramic dies when performing hot indirect extrusion of aluminum or its alloy materials using ceramic dies, particularly after extrusion processing. The present invention relates to a method for preventing damage such as cracking to a ceramic die part due to a large impact force applied when removing pressed waste.

Conventional technology When extruding ρ-Cu-based high-strength aluminum alloys or so-called high-concentration aluminum alloys that contain relatively large amounts of additive elements to strengthen the material, it is necessary to suppress the occurrence of surface defects in the extruded material. In order to increase the extrusion speed, as shown in FIG. 1, dies whose die bodies (1a) constituting the bearing portion are made of ceramic have been used.

The problem to be solved by the invention is that extrusion using the ceramic die (1) is often carried out hot and by an indirect extrusion method, but after extrusion of the extruded material (A), Pressed scum (
When removing B), damage such as cracking may occur in the ceramic die body (1a) with low tensile stress. That is, the pressed waste (B) is usually removed by a roller, but since the pressed waste (B) is in close contact with the die (1) surface and the die ring (4) surface due to the extrusion force, in order to remove it, It requires a considerable amount of force, and also
Since the separation of B) occurs instantaneously, the force applied to the shear acts on the die (1) side, and a particularly large impact force acts on the bearing part of the die body (1a). A situation may arise in which the ceramic die body (1a) is damaged.

The present invention aims to provide the simplest means to solve these problems.

Means for Solving the Problems This invention provides that when indirectly extruding AΩ material using a ceramic die, the billet surfaces of A and Q materials and/or the die surface and die ring in contact with the billet are preliminarily extruded. Summary of a method for preventing damage to ceramic dies for indirect extrusion, which is characterized by performing extrusion processing with a mold release agent applied to the surface and reducing the impact force that acts when removing pressed scum after extrusion. shall be.

In the attached drawings of the example, (1) is a ceramic die for indirect extrusion consisting of a ceramic die body (1a) and a die case (2) that constitute a bearing part, (3) is a backer, and (4) is a die. The ring (5) is a di-stem.

The die body (1a) is made of ceramics such as zirconia, silicon nitride, and sialon, and is fixed to the steel die case (2) by shrink fitting to a state where a predetermined compressive stress is applied from the surroundings. ing.

In carrying out this invention, when extruding an Al material such as a high-concentration AΩ alloy using the above-mentioned extrusion apparatus, the aluminum material billet surface or the extrusion mold surface directly in contact with the billet, that is, the die (1) and die Extrusion processing is performed using a ring (4) with a mold release agent applied to the front surface. As the mold release agent, for example, a dispersion of graphite in a solvent, boron nitride, molybdenum disulfide, etc. can be suitably used. The release agent may be applied only to the side of the billet that is in contact with the extrusion die, or it may be applied only to the above-mentioned extrusion die side, or it may be applied to both sides. good.

Then, after completing the extrusion process according to a conventional method with the above-mentioned mold release agent applied, the pressed waste (B) is coated with the extrusion agent (A) using a shear.
At this time, the mold release agent is present between the pressed waste (B) and the die (1) surface and die ring (4) surface, so that the mold release agent itself is removed. It becomes possible to separate them with a small amount of force. Therefore, the amount of force required for the tire can be significantly reduced.

Incidentally, when extrusion processing is performed without applying any mold release agent, the shearing force required to separate and remove the mold release agent is about 100 tons, but the release agent made of graphite dispersion on the billet surface is When the extrusion process was performed after applying the filler thickly, the shear force required to remove the pressed scum could be reduced to about 50 tons. Therefore, during this removal, the impact force applied to the die (1) side can be reduced in accordance with the reduction in the above-mentioned force, and as a result, the impact force applied to the ceramic die body (1a) can be reduced. can.

Effects of the Invention According to the present invention, as described above, it is possible to significantly reduce the mechanical impact force applied to the die surface and ultimately to the ceramic die body during the work of separating and removing pressed scum after extrusion processing. As a result, it is possible to prevent damage such as cracking to the die body due to the removal operation, and it is possible to obtain the remarkable effect that the useful life of the die body can be extended.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing the relationship between the pressed waste and the die after extrusion when the indirect extrusion method to which the present invention is applied is employed.

Claims (1)

[Claims] When hotly extruding Al material using a ceramic die, extrusion processing is performed with a release agent applied in advance to the Al material billet surface and/or the die surface and die ring surface in contact with the billet. A method for preventing damage to ceramic dies for indirect extrusion, characterized by reducing the impact force that acts when removing pressed waste after extrusion.