JPS6216728B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for indirect extrusion of metal billets, the purpose of which is to remove the skin of the billet left on the inner surface of the container by utilizing the time when the billet is loaded into the container. The aim is to improve the operating rate.

Conventionally, the indirect extrusion method for metal billets differs from direct extrusion methods in that there is no friction between the metal billet and the billet loading hole of the container that holds it, so there is no generation of frictional heat during extrusion molding. Also, there is no risk of causing a confusing flow of metal within the billet, and the pressing force is not related to the length of the billet, so it is widely used because it has the advantages of being able to extrude a large billet with a small force. It is used. However, on the other hand, there is a risk that oxides, segregation layers, and other impurities in the billet skin may be extruded onto the surface of the profile as part of the product, or may be incorporated into the product, reducing the quality of the product. It has certain drawbacks.

Methods to prevent this include, for example, cutting and removing the skin of the billet by machining before extrusion molding, or attaching the skin of the billet to the inner wall surface of the billet loading hole of the container during extrusion molding. A method has been proposed in which only the high-quality parts are extruded into products. However, the former method requires machining, and the latter method involves inserting a cleanout disk with the same diameter as the billet loading hole after extrusion and before feeding the billet into the billet loading hole. It is necessary to remove the skin of the billet adhering to the inner wall surface of the loading hole, and in both cases, a special process is required in the extrusion process, resulting in poor operating efficiency.

The present invention aims to solve the above problems,
The outer periphery of the tip of the die block attached to the tip of the stem contracts due to extrusion pressure during extrusion and creates a clearance with the inner wall of the container so that the billet skin remains on the inner wall of the container, and when returning, the elastic restoring force causes the billet to close to the inner wall of the container and close to the inner wall of the container. This is an indirect metal billet extrusion device characterized by being provided with a protruding ridge portion for scraping out the billet skin portion left on the outside of the container.

That is, in the present invention, when the billet skin is left on the inner wall of the container during extrusion, the protruding ridge on the outer periphery of the tip of the die block attached to the tip of the stem is automatically removed by the extrusion pressure during extrusion, without using a clean out desk. A clearance is created between the stem and the inner wall of the container, and the elastic restoring force allows it to automatically approach the inner wall of the container when returning, so just by pushing out and returning the stem, the billet skin part can be removed. It is possible to obtain a high-quality extruded material by leaving it on the inner wall of the container, and also to reliably remove the billet skin part adhering to the inner wall of the container to the outside of the container. Unlike the conventional method, there is no need to specifically incorporate a step of removing the billet skin portion during the extrusion cycle and a special mechanism associated therewith, and thus the extrusion operating rate can be improved. Further, since the billet skin portion is removed on the opposite side of the die, there is no fear that the once removed billet skin portion around the die will be caught in the molded product during extrusion. The device itself can also be configured very easily. Next, examples will be described.

FIG. 1 is an enlarged perspective view of a die block 3 according to an embodiment of the present invention, in which a slightly elastic collar-shaped ridge 4 is provided around the tip. As shown in FIG. 2, when the billet B is extruded in the container 1, the protrusion 4 is compressed by the pressing force, and the outer circumference and the inner wall of the container 1 are compressed. A clearance is created between the billets, leaving the billet skin part a on the inner wall surface, and only the high-quality parts inside the billet are extruded.

Next, when loading the billet after extrusion molding, as shown in FIG. Due to the relative movement of the ridges 4, the billet skin part a adhering to the inner wall of the container is scraped off and removed.

The present invention is as described above, and in addition to obtaining a high-quality extruded material by leaving the billet skin part on the inner wall surface of the container during extrusion molding, the clean-out of the billet skin part adhering to the inner wall of the container is performed in a special manner. Since it can be carried out without going through any steps, it is effective in improving the operating rate of extrusion molding.

[Brief explanation of the drawing]

FIG. 1 is an enlarged perspective view of a die block according to an embodiment of the present invention, FIG. 2 is a cross-sectional view during extrusion, and FIG. 3 is a cross-sectional view during billet loading. DESCRIPTION OF SYMBOLS 1... Container, 2... Stem, 3... Dive block, 4... Ridge part, a... Billet skin part, B... Billet.

Claims (1)

[Claims] 1 At the outer periphery of the tip of the die block attached to the tip of the stem, during extrusion, the die block contracts due to extrusion pressure and creates a clearance with the inner wall of the container so that the billet skin remains on the inner wall of the container, and when returning, it approaches the inner wall of the container due to elastic restoring force. An indirect extrusion device for metal billets, characterized in that a protruding ridge portion is provided to scrape out the billet skin portion left on the inner wall of the container to the outside of the container.