JPS61137624A - Composite material billet for extrusion working - Google Patents

Abstract

PURPOSE:To decrease die wear and to improve the surface of a composite material billet in pressure casting of the molten matrix metal or alloy of the molding of a compressed and heated reinforcing material by forming a thick matrix layer to the head part at a specific ratio of the overall length and subjecting the metal or alloy to extrusion. CONSTITUTION:The matrix layer corresponding to 2-10% of the overall length is formed to the head part in the stage of forming a composite member by pressure-casting the molten matrix metal or alloy to the molding of the reinforcing material formed by compressing and heating SIC whisker or short fibers of Al2O3, etc. Such composite member is subjected to extrusion by a die, then the cracking on the surface is decreased and tearing is decreased as well. The good composite material billet for extrusion working is thus obtd. The die wear is decreased and the effect is industrially high.

Description

[Detailed description of the invention] Industrial applications Billet for extrusion processing.

Prior Art Stc whiskers or M2O3 short fibers are formed into a molded body with a volume of 10 to 20, and the molded body is impregnated with molten metal by pressure casting to obtain a composite billet with the short fibers. A composite material having a desired cross section is obtained by applying hot pressure to the composite material billet and continuously extruding it into a long length through one or more die holes.

Problems to be Solved by the Invention However, in such conventional products, cracks occur on the surface of the extruded material during the extrusion process, and the die is severely worn, and furthermore, metal adheres to the die, resulting in damage to the extruded material. There are problems such as tearing on the surface of the material, making it impossible to obtain a desirable extruded material. In particular, the larger the volume ratio of the reinforcing material or the higher the high-temperature deformation resistance value of the matrix, the more significant the deterioration of the surface of the extruded material.

``Structure of the Invention'' Means for Solving the Problems A method for obtaining an extruded material consisting of a reinforcing material and a matrix metal or an alloy by continuous extrusion processing from a die hole, wherein the reinforcing material and the matrix metal or alloy are continuously extruded. A composite material billet for extrusion processing, characterized in that a layer consisting only of the above-mentioned IJ socks or alloy is formed on the extrusion tip side of the interlocking tissue portion made of the alloy.

The layer portion consisting only of the matrix metal or alloy formed on the side of the extrusion tip is to be thinly deposited on the surface of the extruded material during extrusion processing, and the inside has a composite structure of reinforcing material and matrix. can get. That is, the surface of the extruded material becomes similar to that of a billet made of only the matrix metal or alloy, and the occurrence of cracks is effectively prevented.

Practical prevention of contact of the reinforcing material with the die Example To explain a specific embodiment of the present invention as described above, for example, a molded body of &C whiskers was heated to 100 mφ x 100 mA so that the volume ratio was 20%. ! After heating the molded body to, for example, around 600°C, the inner diameter is 1.
It is installed in the mold space of a pressure casting machine with a diameter of 100K and a depth of 230m.

Furthermore, matrix AA202 melted in another melting furnace
Approximately 800 i of molten metal of 4 alloy is injected into the mold space, and the upper surface of the molten metal is immediately pressurized by lowering the pressurizing caster of the pressurizing caster (for example, 10004 molten metal, the molten metal is impregnated into the &C whisker molded body.Furthermore, Pressure is continued until the molten metal in the StC Quisker molded body finishes solidifying.

The structure of the composite billet of StC Quisker and matrix AA2024 alloy thus obtained is shown in FIG. That is, the bottom #) 100m
Up to a height of 20% by volume of the &C whisker molded body, a composite billet is obtained which has a matrix AA2024 alloy part 2 with a thickness of 5 mm on the front surface, which does not contain any &C whiskers. The above-mentioned &C whisker molded body is suitably At20. Reinforcements such as short fibers can be employed in place of the StC coquiskers, and such reinforcements typically have a thickness of 0.1 to 20 μm and a length of l to io, o.
It is on the order of ooμm.

Further, as the matrix, aluminum or an alloy thereof is appropriately employed, and magnesium, titanium, copper, etc. can be used depending on the case. Furthermore, the degree of solubility of such a matrix metal molten metal is determined by considering its composition (
For aluminum alloys, the temperature is generally 700-800°C.

As for the volume ratio of the reinforcing fiber material such as whiskers and the matrix, the reinforcing material may have a volume of about 10 to 20, which is the same as in the conventional case, but in some cases it may be about 30. The pressure for impregnating the above-mentioned molten metal can be appropriately selected by taking into account the amount and properties of the reinforcing material, the temperature conditions of the molten metal as mentioned above, and generally 100 -1
,000 minW.

In order to remove the mold release agent during pressure casting on the surface of the billet obtained as described above, it is cut to an outer diameter of 98 mm and a height of 103 mm. After the solid billet is homogenized, for example, the container temperature is 400°C and the billet preheating temperature is 480°C.
The billet was placed in a container equipped with a 2011φ die with the S-C whisker-free portion facing forward, and an extrusion force was applied to the billet to extrude a 20mmφ rod.

The extruded rod thus obtained has a surface of 0, 1 to 0
．． It has a layer consisting only of matrix AA 2024 alloy with a thickness of 5 wafers, with an internal structure consisting of Si, C whiskers and matrix AA 2024 alloy composite. The surface quality of the extruded rod is very good, similar to that of the extruded rod of 2024 alloy.

In addition, for comparison, an extrusion test was conducted using a conventional method using only a billet without a layer consisting only of matrix, but the extrusion speed was 0, which was the lowest extrusion speed that could be tested.
Even under the condition of 2 m/min, tearing 4 occurs on the surface of the extruded round bar as shown in FIG. 2A. In addition, the minimum extrusion degree that can be tested at this time is Hl, 0Vmi with a normal factory extruder.
Although it cannot be controlled below n, the inventors made careful adjustments to the equipment and achieved a value of 0.27FI/rII.
This allows up to Iin. However, it is difficult to maintain this speed constant, and the speed is not necessarily stable.

On the other hand, in the method according to the present invention, the extrusion speed is set at 1.0 m
Figure 2 (B
An extruded rod 3 as shown in ) was obtained.

As described above, the present invention prevents the matrix metal from the layer consisting only of the matrix at the tip of the billet from covering the surface of the composite material until the end of extrusion, thereby avoiding friction between the die and the composite material. This was based on the discovery that adhesion between the die and the composite material could be prevented.

Extruded materials made of composite materials are used as products made by cutting after extrusion processing or as materials for forging. In these cases, the thickness of the inhomogeneous layer (layer consisting only of matrix) on the surface of the extruded material should be as thin as possible; however, since 1 m is usually cut in the trench, a thickness of 11 degrees per 1 m is permissible. .

Moreover, the thickness of the heterogeneous layer of the extruded rod is determined by the extrusion.

determined by the ratio and the thickness of the matrix-only layer at the tip of the composite billet.

From this fifth-order point, we calculated the relationship between the thickness of the tip layer consisting only of matrix and the thickness of the extruded material surface layer, and found that at an extrusion ratio of 6:1 or more, the thickness of the tip layer is 10% of the billet length. If it is below, the thickness of the surface layer of the extruded material after 10α from the tip of the extruded material is 1. It was found that the value is lower than that of Osaw. Furthermore, if the billet tip layer thickness is less than 296 times the billet length, a minute rack will occur on the surface of the extruded material at the end of extrusion when the extrusion ratio is less than 25:1. Therefore, the appropriate thickness of the billet tip layer is
It is known that the total length of the billet ranges from 2 inches to 10%.

Production example I Mz Q 3 short fiber volume ratio 25chi, matrix AA6
061, billet tip layer thickness 2mm diameter 9811
A 1% composite billet with a height of 102 mm was produced by pressure casting, and the composite billet was extruded at 600 tons/extruder at an extrusion rate of 0.6 ml1n.

It was extruded into a 110 mm x 40 flat plate at an extrusion ratio of 20:1. That is, in this case, an extruded flat plate with a good surface and no cracks was obtained.

Production example 2 &C whisker volume ratio 20cm, matrix AA201
4. Diameter 150w5 with billet tip layer thickness 10 fins
Composite material billets in the order of height x 50 are manufactured by pressure casting method,
Extrusion speed 1.0 in a 2000 ton extruder? 7
A 40 Mφ round bar was extruded at I/mln and an extrusion ratio of 14:1. In this case, it was possible to obtain an extruded round bar with good surface properties without any cracks or tearing on the surface. In addition, the state of wear and tear on the die was examined after 30 extrusions, but almost no wear could be determined.

"Effects of the Invention" According to the present invention as explained above, cracks are less likely to occur on the surface of the extruded material during extrusion processing, and it is possible to obtain an extruded material with excellent storm-like properties without the occurrence of steering. It is possible to carry out an advantageous extrusion operation with less wear on extrusion dies, and this invention is industrially highly effective.

[Brief explanation of drawings]

The drawings show the technical contents of the present invention, and FIG. 1 is a perspective view of a composite billet according to the present invention, and FIG. 2 is an extruded bar showing the state of occurrence of tearing and an extruded bar according to the present invention. FIG. 3 is a side view shown together. In these drawings, reference numeral 1 indicates a composite member section, 2 indicates a matrix alloy section, 3 indicates an extruded bar, and 4 indicates tearing on the surface thereof. Patent applicant Nippon Light Metal Co., Ltd. Inventor Osamu Watanabe - Akira Ajimura Bema Masaru Saito
Gidai/ugi No. 2

Claims (1)

[Scope of Claims] 1. A composite structure part for obtaining an extruded material made of a reinforcing material and a matrix metal or alloy by continuous extrusion processing from a die hole, the composite structure being made of the reinforcing material and the matrix metal or alloy. A composite material billet for extrusion processing, characterized in that a layer consisting only of the above matrix metal or alloy is formed on the extrusion tip side. 2. The composite billet for extrusion processing according to claim 1, wherein the thickness of the layer consisting only of the matrix metal or alloy is 2 to 10% of the total length of the billet.