JPS6064724A - Extruding method of aluminum material having hard extruding property - Google Patents

Abstract

PURPOSE:To hot extrude a composite billet having a hard-extruding aluminum material as a solid core body while restricting the generation of tearing phenomenon, by forming previously a dead metal-layer of easy-extruding aluminum material. CONSTITUTION:In hot rolling a hard-extruding alminum material such as Al- Mg alloy; an easy-extruding alminum material such as an Al-alloy obtained by previously adding a pure Al or the least amount of B, etc., is hot extruded, or a hard-extruding alminum billet is hot extruded by interposing the easy-extruding aluminum material to the front of the billet, to form a dead metal-layer of easy- extruding material.Next, a composite billet, formed by coating the easy-extruding aluminum material on the surface of side part of the hard-extruding aluminum material to be used as a solid core body so as to coat it thick at the front- end side and thin at the rear-end side, is hot extruded. In this way, the workability in extrusion of a hard-extruding material is improved.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for hot extrusion of an aluminum material that is difficult to extrude, such as an A#-Mg alloy, and more specifically, the present invention relates to a hot extrusion processing method for an aluminum material that is difficult to extrude, such as an A#-Mg alloy. After forming the dead metal layer,
The present invention relates to a method for hot extrusion of an aluminum material that is difficult to extrude, by extruding a composite billet in which a solid core is made of an aluminum material that is difficult to extrude, and the surface is coated with an aluminum material that is easy to extrude.

For example, /1-Mg alloys have excellent corrosion resistance and excellent mechanical properties, so the use of extruded mold materials thereof is expanding. However, when the Mg content is high, such as in 5056 alloy, extrusion processability is poor, tearing phenomenon tends to occur on the surface of the pressed pile material, and the hot extrusion process limit is also low. Other person β
The same can be said of high aluminum alloy materials such as -Cu-Mg alloy and A12-Zn-Mg alloy. Therefore, there is a desire to develop means to improve the hot extrusion processability of this type of alloy and increase the processing limit. For example, by improving the die shape, Proposal of a method to reduce the difference in external movement speed (plasticity and processing, νol.

23, No. 256.437-443 (1982)),
In addition, as a means of improving extrudability, B, Be, Ti,
A method of extrusion molding with an aluminum alloy intervening piece containing at least one of the elements Zr, W, Mo, and V (Japanese Patent Publication No. 55-25931), in which the surface of a metal billet is preliminarily coated with vitreous material. Thickness 0 consisting of lubricant
．． A method of forming and extruding a lubricating coating layer of 0.01 to 0.5 yen (Japanese Unexamined Patent Publication No. 53-133562) has been proposed.

Furthermore, the present inventors have proposed the 61st (1981) and 62nd
Female extrusion processability 5 at the Light Metals Society of Japan (1982)
Extrusion achieved by hot extrusion using a 05G aluminum alloy billet coated with pure aluminum of a certain thickness, with a pure aluminum plate interposed between the forming die and the billet. He is presenting research on the effects of sex improvement.

Based on the current state of the technology, the present inventors further advanced their previous research and conducted intensive studies to develop an industrially suitable hot extrusion processing method for aluminum materials that are difficult to extrude. The invented method has been completed.

That is, in the present invention, when hot extruding an aluminum material that is difficult to extrude, an easily extrudable aluminum material is hot extruded in advance, or an easily extrudable aluminum material is placed in front of a billet of an aluminum material that is difficult to extrude. A dead metal layer made of an easily extrudable aluminum material is formed by hot extrusion with the intervening aluminum material, and then a solid core is made of an aluminum material that is difficult to extrude, and the side surface of the dead metal layer is made of an easily extruded aluminum material. An object of the present invention is to provide a method for extruding a difficult-to-extrude aluminum material, which comprises hot-extruding a composite billet in which the aluminum material is coated thickly on the front end side and thinly on the rear end side.

The method of the present invention will be explained in more detail below.

In the present invention, a difficult-to-extrude aluminum material is not defined by any absolute index, but rather refers to an aluminum material that has relatively poor extrusion workability and for which improvements in processing limits are desired, such as Mg content. A4-Mg with high
Aβ alloy, known as high-strength aluminum alloy
-Cu-Mg-based alloy, Aβ-Zn-Mg-based alloy, etc., further reinforced with poron, carbon, silicon carbide, or alumina-based fiber, an aluminum composite material,
Examples include powdered sintered aluminum material.

On the other hand, easily extrudable aluminum materials include, for example, pure aluminum to which trace amounts of boron, titanium, etc. may be added, Aβ-Mg-3 alloys known as easily extrudable aluminum alloys such as 6063, and 7072. etc. An-
Zn-based alloys, Aβ-Mn-based alloys such as 3003, etc., have relatively excellent extrusion processability compared to the former.

In the method of the present invention, first, an easily extrudable aluminum billet is hot extruded, or a short piece of easily extruded aluminum material is sandwiched between a difficult-to-extrude aluminum composite billet and a molding die, which will be described later. At least extrusion processing is performed, and a dead metal layer, which is formed along the back surface of the molding die and the wall surface of the container during the extrusion process, is formed in advance from an easily extrudable aluminum material. Formation of a dead metal layer by such easily extrudable aluminum coating and use of a composite billet made of a solid core made of an aluminum material that is difficult to extrude and coated with an easily extrudable aluminum material, which will be described later, make it difficult to extrude. The tearing phenomenon that occurs during pouring during extrusion of workable aluminum materials can be significantly suppressed, and the extrusion workability is greatly improved.

The composite billet used in the method of the present invention has a solid core made of the above-mentioned difficult-to-extrude aluminum material, and the side surfaces of the billet are coated with the above-mentioned easily extrudable aluminum material, and the thickness of the coating layer is The thickness of the easily extrudable aluminum material formed on the surface of the extruded product should be determined by the N thickness, extrusion ratio, etc. In this case, the thickness of the coating layer on the side surface of the composite billet is the thickness on the front end side. It needs to be formed thickly and gradually become thinner toward the rear end.By controlling the thickness of the coating layer in this way, it is possible to form an extrusion material having a uniform coating layer of easily extrudable material. On the other hand, when the thickness of the side surface coating layer of the composite billet is constant, the thickness of the coating layer of the extruded mold material tends to gradually increase as extrusion progresses.

That is, if the ratio of the billet diameter to the coating layer thickness in the composite billet is A, and the ratio of the diameter to the coating layer thickness in the extruded product material is B, the ratio B/A will be smaller than 1. For this reason, in a composite billet having a coating layer of uniform thickness, the above ratio A gradually increases as the extrusion process progresses, and as a result, the ratio B also increases, resulting in the inconvenience that the coating thickness of the product shape differs. . Furthermore, the thickness of the coating layer of the composite fin/throat does not necessarily have to be formed with a certain gradient, being thicker on the front end side and thinner on the rear end side; Even though the thickness of each coating layer is different, short billets and throats each having a uniform coating layer thickness are created, and they are arranged in order from the thickest coating layer to form a long billet. It is also possible to simulate the composite fin 71- used in the present invention.

In the above method, a short billet of easily extrudable aluminum material is extruded in advance to form a de]F metal layer, and then an aluminum grinding fin and throat that is difficult to extrude is extruded intermittently or continuously. Although the composite billet has been described, another embodiment is a composite billet/nod having a structure in which the easily extrudable aluminum material short-sized Pireno 1- and the composite billet are integrated, that is, a solid core of the difficult-to-extrude aluminum material. It is also possible to use a composite billet in which the front end and side surfaces of the body are made of easily extrudable aluminum material and are integrally formed in an open chain manner. The schematic form of such a composite fin/throat is shown in longitudinal sectional views in FIGS. 1 to 3.

By using the composite billet, the easily extrudable aluminum material on the front end face is first extruded to form an effective dead metal layer made of the easily extrudable aluminum material, and then the difficult to extrude aluminum material is continuously extruded. Extrusion can proceed. In Fig. 1, the easily extrudable aluminum material l present on the front face of the billet has a certain thickness necessary for forming a dead metal layer, and in the other examples of appearance shown in Figs. It is a composite billet in which the easily extrudable aluminum material 1 is made to approximate the shape of the dead metal layer formed during extrusion processing, and is formed integrally with the coating layer 2 on the surface of the side surface, and it is also possible to use such a composite billet. It is effective in the invention method. Note that 3 indicates a solid core made of an aluminum material that is difficult to extrude.

Furthermore, the shape of the solid core made of a difficult-to-extrude aluminum material does not necessarily have to be the same cylindrical shape as the billet. It can be selected arbitrarily depending on the shape of the mold material.

Let's talk about the manufacturing method of such composite fins and throats.
This method does not necessarily require (but can be obtained by appropriately combining conventional/lt used casting technology and metal processing technology. For example, focusing on a cylindrical solid core body. , by casting pure aluminum material etc. on the surface of the billet, and if necessary, post-processing to finish it into the desired composite billet.

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In addition, the extrusion processing conditions for the composite fillet and throat using an easily extrudable aluminum material and difficult-to-extrude aluminum 44 as a solid core for forming a dead metal layer are conditions that are heavily used in this industry. By carrying out the method of the present invention, the occurrence of tearing phenomenon in aluminum materials that are difficult to extrude is significantly suppressed, and as a result, an increase in extrusion speed can be achieved.

In addition, when carrying out the method of the present invention, an alloy with corrosion resistance, such as 7072 alloy, which can improve the corrosion resistance of the core body as the aluminum material for forming the surface coating layer, is selected on the surface of the extruded material. It is also possible to improve the surface treatment properties of product shapes by forming a surface coating layer or by combining materials.

According to the method of the present invention described in detail above, a dead metal layer is formed in advance using an easily extrudable aluminum material, and then a dead metal layer is formed using an easily extruded aluminum material having a thick slope on the front end side and a thin slope on the rear end side. By hot extruding a composite billet whose solid core is made of a hard-to-extrude aluminum material with a side surface coating layer, the tearing phenomenon during extrusion can be significantly suppressed. The extrudability of the material can be significantly improved. In addition, by selecting the surface coating layer, secondary effects such as improvement in corrosion resistance and surface treatment properties can be expected, and the industrial value thereof is enormous.

The method of the present invention will be explained in more detail by examples below.
The present invention is not limited to such examples.

Example 1) Production of composite billet The chemical compositions of the core material 5056 alloy and the covering material 1070 alloy are shown in Table 1.

First, the surface was machined using alloy 5056 with a diameter of 162 mφ.
Continuously cast material is used as a core body, fixed inside a mold, and 1070 pure aluminum molten metal is poured between the mold and the core body to obtain a composite ingot, and its outer shape is machined to specified dimensions. Composite Pireno 1~ was produced. FIG. 4 shows the general shape of the obtained composite billet, and Table 2 shows the dimensional specifications of the billet.

Table 1 2) Extrusion test For the composite billet obtained by the above method, 2350
Using a ton extrusion press, the extrusion temperature was 450°C, and the extrusion ram speed was V = 7, 5 m/sec.
Extrusion processing was performed using a single hole die for round bars (extrusion ratio R-38) to obtain a round bar of 30 mφ.

The surface condition of the obtained round bar was similar to that of the round bar obtained through an extrusion test under the same conditions of 5056 alloy without surface coating used for comparison, which exhibited a significant tearing phenomenon. All of them exhibited fully satisfactory surface conditions, and also showed the possibility of significantly increasing extrusion speed.

Furthermore, the cross section of the obtained round bar was inspected and the relationship between the length of the mold material and the thickness of the coating layer was measured, and the results are shown in FIG.

As is clear from FIG. 5, it has been proven that when a composite fillet 7 having a tapered side surface coating layer according to the method of the present invention is used, a product having a substantially constant coating layer can be obtained; For composite billets having a constant coating layer thickness, the coating layer thickness on the surface of the resulting product tends to increase as the extrusion process progresses, making it impossible to obtain a product having a constant coating layer.

[Brief explanation of the drawing]

1 to 3 are schematic vertical cross-sectional views illustrating composite billets suitable for carrying out the method of the present invention, and FIG. FIG. 5 is a diagram showing the results of measuring the displacement of the coating layer thickness in the longitudinal direction of the product profile obtained in the example of the present invention. In the figure, l... Front end of the composite billet easily extruded aluminum material 2... Easily extruded aluminum material on the side surface of the composite billet 3... Difficult to extrude aluminum material solid core Figure 1 Figure 20 ``Dan Figure 3 U Figure 4 Fumin HL 8 Format, LB Story 1'' JC 50 2d O Sai 4ε,:! (mm) Procedural amendment (voluntary) 1. Indication of the case Patent Application No. 171755 of 1982 2. Name of the invention Extrusion processing method for aluminum material that is difficult to extrude 3. Person making the amendment Relationship to the case Patent applicant Address: 5-15 Kitahama, Higashi-ku, Osaka Name: Sumitomo Aluminum Smelting & Refining Co., Ltd. (and 1 other representative: Heizo Mitsuben 4, Agent residence: 2-7-9 Nihonbashi, Chuo-ku, Tokyo) Sumitomo Aluminum Smelting & Refining Co., Ltd. Technical Department 5, Detailed Description of the Invention Column 6 of the Specification Subject to Amendment, Contents of the Amendment (1) In the second line of page 10 of the specification, the phrase “requires a method” has been changed to “requires a method”. (2) In the 13th page, line 11 of the specification, the phrase ``does not involve'' is amended to ``involve''. (above)

Claims (1)

[Claims] 1) When hot extruding an extrudable aluminum material, an easily extrudable aluminum material is hot-extruded in advance, or an easily extruded aluminum material is placed in front of a difficult-to-extrude aluminum billet. Hot extrusion processing is performed with an extrudable aluminum material interposed to form a dead metal layer composed of the easily extrudable aluminum material, and then a solid core made of the difficult to extrude aluminum material is formed on the side surface thereof. A method for extruding an aluminum material that is difficult to extrude, characterized by hot extruding a composite billet whose surface is coated with an easily extrudable aluminum material thickly on the front end side and thinly on the rear end side. 2) A patent claim that uses a composite billet in which an easily extrudable aluminum material FFtZ having a thickness necessary for forming a dead metal layer is formed on the front end surface of the composite billet integrally with a coating layer on the side surface of the composite billet. The method described in Scope 1. 3) The method according to claim 2, which uses a composite billet in which the coating layer on the front end face of the composite billet is formed to approximately approximate the shape of the dead metal layer during extrusion processing.