JP2002018557A - Method for producing thin-walled metallic product and its producing apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a product having comparatively uniform metallurgical structure and little defect even in a thin-walled product. SOLUTION: A method for producing a thin-walled metallic product has such a feature that, after producing a plate material by supplying molten metal into rolls and it is rapidly cooled and solidified, then it is cut off to a prescribed size and the cut-off plate material is heated up to semi-melting state in a continuous heating furnace, and is then supplied into a pressing means and formed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method and an apparatus for producing a thin metal product. More specifically, the present invention relates to a method and an apparatus for manufacturing a thin-walled metal product using semi-solid molding of a light alloy.

[0002]

2. Description of the Related Art In many cases, parts are made of light alloys in order to reduce the weight of products. However, there is an increasing demand for lighter parts, even for light alloy parts, to be further thinned. Thin-walled parts made of aluminum alloys and magnesium alloys represented by cases of personal computers and home electric appliances are manufactured by press working, die casting, thixo molding, and the like.

[0003]

However, these methods have the following advantages and disadvantages, and none of them can completely satisfy the performance required by customers.

[0004] That is, although thin-walled shapes can be formed by press working, the thickness of the material is 5 mm because the material used is a rolled plate.
It is difficult to produce the following thin plates in one step, and it is necessary to repeat rolling to reduce the thickness to 5 mm or less, resulting in high material costs. Also, there is a limit to the shape that can be molded at once,
In order to form a complicated shape, it is necessary to perform pressing multiple times, and it is not possible to form a boss shape for a component mounting screw, so that it is necessary to separately mount a boss component, thereby increasing costs.

[0005] In addition, although die casting has a relatively high degree of freedom in shape, there is a limit to the extent to which the molten metal can be poured, and the quality of internal defects or appearance quality is insufficient and there are many defects when trying to form a thinner product.

Further, generally, the material used for semi-solid molding is a material obtained by solidifying a molten metal by mechanical or electromagnetic stirring while re-heating the solid to a semi-molten state, or heating a chip-shaped material by heating in a screw. It is known that injection molding is used. However, since the material made by the former method is a billet shape with a cylindrical cross section, in order to form a thin product by die casting or pressing in a semi-molten state, the material must be greatly deformed and the shape can be limited. was there. Also, in the latter case, the injection speed cannot be increased so much that there is a limit to the size of the product that can be molded, and when the temperature is increased, the liquid phase and solid phase separate during molding in a semi-molten state, and the metal structure is reduced. There was a problem that the quality became uneven due to unevenness.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and has been made in the art. It has been found that the above-mentioned problems can be solved by molding.

[0008] According to the present invention, rapid solidification using a roll makes it possible to produce a thin plate having a thickness of 5 mm or less, which could not be produced by one conventional process, and eliminates the step of reducing the thickness to 5 mm or less by rolling. be able to.

Further, since the thin plate produced by the method of the present invention has a high cooling rate, when reheated to a semi-molten state, the spheroidization of primary crystals is promoted and the flowability is improved, which is suitable for semi-solid molding. In addition, when the cooling rate is high, the primary crystals become small, and it is difficult to separate or lose the liquid phase in a semi-molten state. Also, the eutectic Si of a thin aluminum alloy plate becomes more uniform and finer when the cooling rate is higher. Rapid solidification is also effective to make eutectic Si uniform and fine even after semi-solid molding. Therefore, it can be directly used as a material for semi-solid molding for producing a thin metal product.

Further, in the conventional twin-roll caster for aluminum alloy, only the baffle plate having both flat front and back surfaces is manufactured. However, according to the present invention, the shape of the roll is devised to extend the entire circumference of the roll surface. It is possible to manufacture a continuous projection on the book board by attaching a mark, and a thin plate having a projection at a predetermined position by making a depression at a predetermined position on the roll surface. Forming the projections is effective for forming bosses and the like during semi-solid processing.

In the conventional twin-roll caster for aluminum alloys, it is possible to produce only a thin plate having a constant width. However, according to the present invention, it is possible to mount a heat insulating ring on the roll surface. By reducing the transfer of heat between the roll surface and the molten metal in that part, a part where the molten metal does not solidify is created. It is possible to produce thin plates of various planar shapes. It is possible to manufacture a thin plate according to the shape of the product at the time of semi-solid processing, and an improvement in yield can be expected.

Further, the conventional twin-roll caster for aluminum alloy can only produce one thin plate, but the twin-roll method according to the present invention can produce a clad material composed of two kinds of alloys. It is. By using such a clad material, a product having two or more types of properties such as strength and lightness, abrasion resistance, corrosion resistance, surface beautification, and electromagnetic shielding properties can be produced.

Therefore, a thin sheet material is produced while being rapidly cooled and solidified by using the above-described method, and the thin sheet is heated to a semi-molten state in a continuous heating furnace, and the material is supplied to a pressing means and molded. The present inventors have discovered that the deformation of the material is not so large even in the case of a large thin-walled shape, which was difficult to form with the thixomold, and the molding was made possible, leading to the present invention. Embodiments of the present invention will be described below in detail with reference to the drawings.

[0014]

FIG. 1 is a flowchart of a method for manufacturing a thin metal product according to the present invention. FIG. 2 is a schematic view of a sheet material manufacturing means for manufacturing a sheet material by supplying a molten metal to one or two rolls and rapidly solidifying the molten metal. FIG. 3 is a schematic view of the cutting means. FIG. 4 is a schematic diagram of the heating means. FIG. 5 is a schematic diagram of the pressing means. FIG. 6 is a micrograph of the metal structure when heated to a semi-molten state. FIG.
To FIG. 10 are schematic diagrams of a roll shape and a plate material obtained by the roll and the like.

FIG. 2 is a schematic view of a sheet material producing means for producing a sheet material by supplying molten metal to one or two rolls and rapidly solidifying it. The sheet material production means is a copper roll 1 (φ250 mm) rotated at a peripheral speed of 30 m / min and a width of 20 mm.
A molten metal 3 of an aluminum alloy is supplied in a molten state from a nozzle 2 made of a refractory as described above to produce a rapidly solidified thin plate material (plate material) 4 having a thickness of 2 mm. The number of rolls may be one (A) or two (B) and (C), and the supply of the molten metal can be performed in any of horizontal, vertical and oblique directions to produce a sheet material.

In a normal twin-roll caster for aluminum alloy, a steel roll is used, and a graphite-based release agent is sprayed on the roll surface to prevent the roll and the thin plate from sticking. It is easy to adhere to the surface of a thin plate.
The release agent adhered to the thin plate surface may enter the inside of the product at the time of molding in a semi-molten state and cause a defect. But,
When a copper roll is used, rapid solidification is promoted, so that the thin plate does not stick to the roll. Therefore, there is no need to use a release agent, and there is almost no possibility that a defect caused by the release agent occurs.

FIG. 3 is a schematic view of the cutting means. In the cutting means, the plate 4 can be cut by the band saw 5 according to the size of the molded product. The cutting method may be another method such as a circular saw cutting, a laser cutting, or a water jet cutting, as long as the method can control the metal structure without significantly impairing it.

FIG. 4 is a schematic diagram of the heating means. The heating means places the cut material 4A on the tray 7 and continuously heats it to a semi-molten state. The inside of the continuous heating furnace 6 can be set to an inert gas atmosphere when oxidation of the product surface is not desired. When the material 4A is thin and reheated to a semi-molten state, the material is easily deformed. Therefore, it is better to heat and move the material 4A while holding the shape on the tray 7 or a net-like material. .

FIG. 6 shows a photograph of the metal structure when the sheet material is heated to a semi-molten state. When the sheet material obtained by the method of the present invention is in a semi-molten state, the primary crystal α is spherical.

FIG. 5 is a schematic view of the pressing means. In the pressing means P, the material 4A heated to 600 ° C.
And can be formed by press working. For example, a thin product 9 having a thickness of 1.5 mm can be formed. In addition, it is possible to control the mold temperature of the pressing means P by using an appropriate means.

Hereinafter, the manufacturing method will be described. In FIG. 2, a copper roll 1 rotated at a peripheral speed of 30 m / min has a width 2
From a nozzle 2 made of a refractory of 0 mm, an aluminum alloy (JI
S: AC-4C) is supplied at 660 ° C.
A rapidly solidified sheet material 4 having a thickness of 2 mm was prepared.

Next, as shown in FIG. 3, the plate 4 was cut by a band saw 5 according to the size of the molded product 6.

Then, as shown in FIG. 4, the cut material 4 is placed on a tray 7 and is heated at 600 ° C. in a continuous heating furnace 6.
Until heated. The interior of the heating furnace 6 may be set to an inert gas atmosphere when oxidation of the product surface is not desired. Particularly, Mg alloy is easily oxidized, so it is better to use an inert gas atmosphere.
When the material is reheated to a semi-molten state due to its small thickness, the material 4 is easily deformed. Therefore, the material 4 is heated and moved while maintaining its shape on the tray. The temperature inside the furnace and the temperature of the material were controlled using a temperature sensor and appropriate control means.

Thereafter, as shown in FIG. 5, the material heated to a molten state was put into a mold and formed by press working. As a result, a thin product having a thickness of 1.5 mm was formed. When the internal metallographic structure was examined, a relatively uniform granulated primary crystal structure was observed, and it was confirmed that there were no major defects.

Hereinafter, various roll shapes and plate materials obtained by the rolls will be described with reference to schematic diagrams.

FIG. 7 is a schematic view for explaining a case of manufacturing a partially thick plate material. In FIG. 7, a continuous projection is formed on the book board and a partly thick plate material can be formed by forming a groove extending all around the roll surface by devising the shape of the upper roll. FIG. 8 shows that a thin plate having a projection at a predetermined position can be manufactured by devising the shape of the upper roll and forming a depression at a predetermined position on the roll surface. As described above, in the conventional twin-roll caster for aluminum alloys, only the baffle plate having both flat front and back surfaces was manufactured. However, according to the present invention, the forming of the protrusions is effective for forming the boss or the like during semi-solid processing. It is.

FIG. 9 is a schematic view for explaining a case of manufacturing a deformed thin plate. In Fig. 9, by attaching a heat insulating ring to the roll surface, it is possible to create a part where the molten metal does not solidify by reducing the ripening of the roll surface and the molten metal in that part, and to produce thin plates of various planar shapes. It is. According to the present invention, in the conventional twin-roll caster for aluminum alloys, it is possible to produce only a thin plate having a constant plate width, but a thin plate is produced according to the shape of the product at the time of semi-solid processing. It is possible to improve the yield.

FIG. 10 is a schematic diagram for explaining the manufacture of a clad plate. In FIG. 10, the conventional twin-roll caster for aluminum alloy was capable of producing only one thin plate, but the twin-roll method according to the present invention was capable of producing a clad material composed of two types of alloys. . By using such a clad material, strength and lightness, abrasion resistance, corrosion resistance, surface beautification, electromagnetic shielding, etc.
A product having more than two types of characteristics can be manufactured.

[0029]

According to the present invention, after a molten metal is supplied to a roll and rapidly solidified to produce a plate, the plate is cut into a predetermined size, and the cut plate is heated to a semi-molten state in a continuous heating furnace. Since the material is supplied to the pressing means and molded, a product having a relatively uniform metal structure with less segregation can be obtained even if the product has a small thickness. Also,
Since the molding is performed in a semi-molten state, the molding load can be reduced, and there is a secondary effect that the molding die and equipment are inexpensive. Furthermore, the effect is remarkable, for example, by making the roll surface into a shape that can obtain a desired thin plate shape, a plate material close to the final product can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram showing a flowchart of a method for producing a thin metal product of the present invention.

FIG. 2 is a schematic view of a sheet material manufacturing means for manufacturing a sheet material by supplying molten metal to one or two rolls and rapidly solidifying the molten metal. A indicates a single roll type, and B and C indicate a twin roll type.

FIG. 3 is a schematic view of a cutting means.

FIG. 4 is a schematic view of a heating means for heating a cut plate material to a semi-molten state in a continuous heating furnace.

FIG. 5 is a schematic view of a pressing means for supplying and molding a material.

FIG. 6 is a micrograph of a metal structure when heated to a semi-molten state.

FIG. 7 is an example of a schematic view of a roll shape and a plate material obtained by the roll.

FIG. 8 is an example of a schematic view of a roll shape and a plate material obtained by the roll.

FIG. 9 is an example of a schematic view of a roll shape and a plate material obtained by the roll.

FIG. 10 is an example of a schematic view of a roll shape and a plate material obtained by the roll and the like.

[Explanation of symbols]

 Reference Signs List 1 roll 2 nozzle 3 molten metal 4 plate material 5 band saw 6 tray 7 continuous heating furnace 8 mold 9 molded product

Continuation of the front page (72) Inventor Tetsuji Matsui 3-1-1 Honohara, Toyokawa-shi, Aichi F-term (reference) in Shintoh Kogyo Co., Ltd. Toyokawa Works 4E004 DA13 SD03 SE03 4E087 AA10 BA03 BA04 DB15 DB22 EA11 GA09 HA91

Claims (17)

[Claims] 1. A plate is manufactured by supplying a molten metal to a roll and rapidly cooling and solidifying the plate, cutting the plate into a predetermined size,
A method for producing a thin metal product, comprising heating a cut plate material to a semi-molten state in a continuous heating furnace, supplying the material to a pressing means, and molding. 2. The method according to claim 1, wherein the material of the molten metal is an Al alloy or a Mg alloy. 3. The method for producing a thin metal product according to claim 1, wherein one or two rolls are used. 4. The method for producing a thin-walled metal product according to claim 1, wherein the cut material is placed on a tray or a net and is moved while being heated. 5. The method for producing a thin metal product according to claim 1, wherein the inside of the continuous heating furnace is an inert gas atmosphere. 6. A sheet material manufacturing means for supplying a molten metal to one or two rolls to rapidly cool and solidify to produce a sheet material, a cutting means for cutting the sheet material into a predetermined size, and semi-melting the cut sheet material. An apparatus for manufacturing a thin metal product, comprising: heating means for heating to a state; and press means for supplying and molding a heated material. 7. The thin metal product manufacturing apparatus according to claim 6, wherein the material of the molten metal is an Al alloy or a Mg alloy. 8. The continuous heating furnace according to claim 6, wherein said heating means is a continuous heating furnace which moves the cut material while heating it while being placed on a tray or a net-like material. Equipment for manufacturing thin metal products. 9. The thin metal product manufacturing apparatus according to claim 6, wherein said heating means has an inert gas atmosphere inside. 10. The method for producing a thin metal product according to claim 1, wherein the roll surface is shaped so as to obtain a desired thin plate shape in the method using two rolls. 11. A method of forming a desired thin plate shape on a roll surface, wherein a material of a roll portion forming a side surface of the thin plate is made of a material having a lower thermal conductivity than that of the roll material. The method for producing a thin metal product according to claim 10. 12. The method according to claim 3, wherein in the method using two rolls, a melt of a different component is supplied to each roll to obtain a thin plate of a clad material. The method for producing the thin metal product according to the above. 13. The method for manufacturing a thin metal product according to claim 1, wherein the material of the roll is a copper alloy. 14. The thin metal product according to claim 6, wherein when two rolls are used, the roll surface is shaped to obtain a desired thin plate shape. manufacturing device. 15. The thin metal product manufacturing apparatus according to claim 10, wherein when two rolls are used, a molten metal of a different component is supplied to each roll to obtain a thin plate of a clad material. 16. An apparatus according to claim 6, wherein said roll material is a copper alloy. 17. When the roll surface is shaped to obtain a desired thin plate shape, the material of the roll portion forming the side surface of the thin plate is made of a material having a lower thermal conductivity than that of the roll material. The apparatus for manufacturing a thin metal product according to any one of claims 6 to 9, and claim 16.