JPS61259831A - Extrusion machining method - Google Patents

Abstract

PURPOSE:To work a shape material having no oxidized film, etc., by stopping the extrusion prior to an extrusion remaining length of a billet becoming in the length for starting the shell winding and by stopping prior to the extrusion remaining length of the later staging billet becoming in the shell winding length by the extrusion of the following billet. CONSTITUTION:Both end faces of a preheated billet B is subjected to scaling. The scaling of the billet B peripheral face is performed by a scalper 2 when this billet B is inserted into a container 3 by a stem 1. The material excepting the shell comes in the extrusion aperture 4a of a die 4 when the billet B is pushed to the front part by the extruding stem 1 and is extruded as a shape material S from the front end thereof. The advance of the stem 1 is stopped prior to the extrusion remaining length of the billet B becoming in the length for starting the billet shell winding. The extrusion remaining part of the preced ing billet B is extruded from the container 3 thereafter by inserting into the container 3 the billet B with scaled both end faces and by advancing the stem 1. The extrusion is stopped prior to the extrusion remaining length becoming in the shell winding starting length by working the following billet B similarly and repeated in the same way thereafter.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to an extrusion processing method for continuously extruding a plurality of billets.

BACKGROUND ART Conventionally, for example, extrusion of aluminum (including aluminum alloys; the same applies hereinafter) has been carried out using the following method. That is, after first preheating the cast billet,
This is then subjected to a peeling process to remove the oxide film and dirt on the surface during casting, and then the peeled billet is placed in a container, and the billet is heated with an appropriate heating device to maintain the billet in a specified position. The billet was kept at a constant temperature and in this state the billet was pressed forward by a stem to extrude aluminum. However, as is well known, during extrusion, the flow of material on the surface of the billet is slower than the flow of material in the center, so when the unextruded length of the billet becomes short and reaches a predetermined length, the billet skin rolls from the rear end. The loading starts. The length at which billet skin rolling starts is, for example, about 150 II for an aluminum billet with a diameter of 6 inches and a length of aoomm. By the way, the billet placed in the container is heated and maintained, so even if the billet is peeled before being placed in the container, an oxide film may be formed on the surface again due to this heating, and dirt may adhere to the inner surface of the container. If this happens, this dirt may adhere to the outer surface of the billet, contaminating the outer skin.

When the unpressed length of the billet becomes short and the billet skin is rolled up from the rear end, this unpressed part will contain many foreign substances, and the mold material obtained by extruding this will contain oxides etc. Contains foreign matter and causes defects. Therefore, when the unpressed length of the billet reaches a predetermined length (this length is shorter than the start length of billet skin rolling), the forward movement of the stem is stopped, and while the container is moved forward, the unpressed length is was removed from the container as leftover material. The remaining length of the billet when stopping the advancement of the stem is, for example, about 20 to 50 mm for an aluminum billet with a diameter of 6 inches and a length of somm. Therefore, there was a problem in that the idle time until the next billet is extruded is long, resulting in low processing efficiency. Also, since it is necessary to move the container every time you remove extrusion residue,
It was difficult to maintain the accuracy of the container. Furthermore, there was a problem that the yield of extrusion residual material was poor.

An object of the present invention is to provide an extrusion processing method that solves the above problems.

In this specification, front and rear are based on the extrusion direction, the front refers to the front in the extrusion direction, and the rear refers to the opposite side.

Means for Solving the Problems The extrusion processing method according to the present invention extrudes the billet placed in a container forward, and stops the above extrusion before the unextruded length of the billet reaches the start length of billet skin rolling. The next billet is placed in the container and pushed forward, and the unpressed portion of the preceding billet is all pushed out from inside the container, and the subsequent billet is pushed forward to reduce the unpressed length of the billet. The method is characterized in that the extrusion is stopped before the length reaches the start length of billet skin rolling, and the post-process is performed at least once after the pre-process is completed.

In the above, the number of times the post-process is performed after the end of the pre-process is the number of billets to be continuously extruded minus one.

The example extrusion processing device includes an extrusion stem (1), a scalper (2),
The extrusion processing container (3) and die (4) are arranged in the above order from the rear. Further, although not shown in the drawings, the extrusion processing apparatus is equipped with a die plate, a backer, an end platen, a die ring, etc. as is known in the art.

A dummy block (5) is attached to the front end of the extrusion stem (1).

In such a configuration, in order to continuously extrude a plurality of aluminum billets, first, the billet (B), which has been preheated to a predetermined temperature, is transported to a container by a loader (not shown), and both end faces of the billet are peeled. Perform processing. This billet (B) is inserted into the container (3) by means of the stem (1). At this time, the billet (
B) The peripheral surface is peeled to remove the oxide film from casting the billet (B). The billet (B) placed in the container (3) is heated by a heating device (not shown) and maintained at a predetermined temperature. Then, the billet (B) placed in the container (3) is pushed forward by the extrusion stem (1). Then, the material other than the surface layer of the billet (B) enters the extrusion opening (4a) of the die (4) and is extruded from its front end as a shape material (S). On the other hand, the material in the billet surface layer, which is made of oxides and includes the billet skin with dirt and other substances attached, has a slower flow rate than the material in the center, and flows from the dead metal area along the inner circumferential surface of the container (3).
3) remains within. Then, the forward movement of the extrusion stem (1) is stopped before the unpressed length of the billet (B) reaches the start length of billet skin rolling (see FIG. 1). After that, the extrusion stem (1) is moved back and the container (3) is removed.
The billet (B), which has been taken out from the inside, preheated to a predetermined temperature, and had both ends peeled on a loader, is inserted into the container (3). At this time, the outer peripheral surface of the rear billet (B) is peeled by the scalper (2). In addition, after inserting the billet (B), the extruded stem (1) is slightly retracted and the stem (
1) Bleed air from the side, and then move the stem (1) forward to bring the front billet (B) and rear billet (B) into close contact (see Figure 2). As shown in Figure 2, the rear end of the rear billet (B) protrudes rearward from inside the container (3) and easily gets cold, so during preheating, heat it gradually from the front end to the rear end. It's good to keep it. Then, this rear billet (B) is attached to the extruded stem (1
) to push forward, and first push out all the unpressed portion of the front billet (B) from inside the container (3). At this time, the billet skin of the front billet (B) is transferred to the surface layer of the rear billet (3) due to the frictional force with the inner peripheral surface of the container (3), so that materials containing oxide films and dirt are removed from the die opening. (4
It is not extruded from a). Furthermore, following this, the rear billet (B) is made similar to the above-mentioned front billet (B), and extrusion is stopped before the unpressed length reaches the start length of billet skin rolling. Thereafter, the same procedure as above is performed for the next billet. This operation is repeated for a plurality of billets to continuously produce the shape material (S).

In the above, billet heating temperature, extrusion speed, etc. are the same as in the case of known extrusion processing methods.

Effects of the Invention The method of the present invention includes the steps of extruding the billet placed in a container forward and stopping the extrusion before the unextruded length of the billet reaches the start length of billet skin rolling, and Place the next billet inside the container, push this billet forward, push out all the unpressed portion of the front billet from inside the container, and push the rear billet forward. and a step of stopping the extrusion before reaching the starting length of can be processed continuously from multiple billets. Therefore, idle time can be shortened and extrusion processing efficiency can be improved. Further, since no extrusion residue is generated for each billet, there is no need to move and remove the container every time one billet is extruded, and the accuracy of the container can be maintained.

[Brief explanation of the drawing]

FIGS. 1 and 2 are longitudinal sectional views showing the extrusion process in progress when a plurality of billets are continuously extruded. (3) Container, (B) Billet. that's all

Claims (1)

[Claims] A step of extruding the billet placed in the container forward and stopping the extrusion before the unpressed length of the billet reaches the start length of billet skin rolling, and placing the next billet in the container and Push the billet forward,
extruding all the unpressed portion of the front billet from inside the container, extruding the rear billet forward, and stopping the extrusion before the unpressed length of the billet reaches the start length of billet skin rolling; An extrusion processing method, characterized in that the post-process is performed at least once after the pre-process is completed.