JP2003039131A - Forming method of magnesium alloy-made plate stock - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a forming method of a magnesium alloy-made plate stock capable of manufacturing a lightweight and high-quality magnesium alloy-made thin thickness-forming product having no deformation such as a camber through forging process, using the magnesium alloy-made plate stock as a stock material. SOLUTION: The stock material composed of a magnesium alloy-made plate stock is not preheated and only the die is preheated and warm forging is executed by the die whose stock material is characteristically heated. The thickness of the magnesium alloy-made plate stock is preferably about 1 mm to 5 mm.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for forming a magnesium alloy sheet material by warm forging.

[0002]

2. Description of the Related Art Magnesium has the lowest specific gravity among metallic materials currently in practical use, and is about 2/3 that of aluminum, and has attracted attention as a lightweight material.

However, magnesium alloys are chemically active, and the chips produced by cutting are easily burned, and the crystal structure of magnesium is a close-packed cubic structure (hcp structure).
Therefore, most of magnesium alloys are currently used as casting materials due to poor plastic workability at room temperature, and in recent years, the thixomolding method has attracted attention along with the die casting method.

Regarding magnesium alloys, magnesium alloy members by a so-called casting / forging method in which a cast molded product is forged and a method of manufacturing the same are known (for example, Japanese Patent Laid-Open Nos. 6-172949 and 6-172949). 6
-248402 publication). Further, a magnesium alloy thin-walled member that is forged by a magnesium alloy such as an ASTM standard AM20 alloy or AZ31 alloy having excellent forgeability and a manufacturing method thereof are also known (for example, JP-A No. 11-77214, Japanese Patent Laid-Open No. 11-27
7173).

[0005]

However, in all of the above-mentioned conventional forging forming methods, not only the die used for forming but also the warm forging method of preheating the raw material magnesium alloy to 300 to 500 ° C. is adopted. Therefore, not only is the crystal grain coarsened by heating, which is not preferable in terms of strength, but especially in the forging of thin plate materials, the warpage of the product after molding is a problem, and straightening or cutting in the subsequent process. There is a problem that it is necessary to perform processing and the like, which takes time and labor.

In order to solve the above-mentioned problems, the present inventors have made various studies on a warm forging method, and as a result, obtained the present invention. Forging using a magnesium alloy plate material as a material It is an object of the present invention to provide a method for forming a magnesium alloy plate material, which is capable of producing a lightweight, high-quality thin-walled molded article made of a magnesium alloy without deformation such as warping by molding.

[0007]

In order to achieve the above object, according to the invention of claim 1, the material made of a magnesium alloy plate material is not preheated, only the mold is preheated, and the material is heated. Warm forging is performed by the die. By not preheating the material consisting of plate material,
As a result of various comparative tests, it was confirmed that the molded product has less deformation such as warpage. In addition, since the material is not preheated, it is possible to prevent the crystal grains from being coarsened more than necessary, which is also preferable in strength.

The invention according to claim 2 is characterized in that the thickness of the magnesium alloy plate material is 5 mm or less. The thinner the plate material, the more easily it becomes warped during molding. With a plate material having a thickness of 5 mm or more, warpage is less likely to occur, but forging itself becomes difficult. Therefore, the molding method of the present invention has a thickness of 1 mm to 5 mm.
It is preferable to apply it to a magnesium alloy plate material.

The invention according to claim 3 is characterized in that the mold temperature in the forging is 200 to 350 ° C. If the mold temperature is less than 200 ° C., warpage is likely to occur during molding, and if it is higher than 350 ° C., temperature control of the mold becomes difficult from the viewpoint of the apparatus.

The invention according to claim 4 is characterized in that the forming speed in the warm forging step is 10 to 200 mm / sec.

The invention according to claim 5 is characterized in that the warm forging is coining.

The invention according to claim 6 is characterized in that the working depth of the coining is 50% or less of the thickness of the plate material. If it exceeds 50%, cracking or warping during molding becomes a problem.

The magnesium alloy plate material used in the present invention is ASTM standard AZ31, AZ61A, AZ80.
Extruded materials or rolled materials of magnesium alloys such as A and Z60A are suitable.

Further, the above-mentioned magnesium alloy composed of fine crystal grains having superplasticity is more preferable.

Further, the molded product of the magnesium alloy plate material processed by the method of the present invention, depending on the intended use,
It is preferable to perform anticorrosion treatment such as surface treatment.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Preferred embodiments of the present invention will be described below with reference to the drawings.

1 to 3 show a thin-walled molded product which is forged by the method of the present invention. The molded product 1 has a fine and bent long groove 2 coined in a material made of a magnesium alloy plate. Material thickness is 3-5
The groove 2 has a depth of 0.5 to 2 mm and a width of 2 mm. In the figure, 3 are mounting holes provided at the four corners of the molded product 1.
The mounting hole 3 is punched before coining the groove 2, but may be punched after coining.
The forging process according to the present invention can be applied not only to the coining process described above but also to embossing process, partial indenting process, upsetting process and the like.

Next, a specific molding process of the molded product 1 shown in FIG. 1 will be described. (Example 1) As a magnesium alloy plate material, ASTM
Standard AZ31 alloy (by weight, Al 12.5-
Using a rolled material (thickness 3 mm) of 3.5%, Zn 0.5 to 1.5%, Mn 0.15% or less, and the balance Mg and unavoidable impurities, cut into 150 mm □ × 3 mmt. Made a material that did. On the other hand, the die used for forging is uniformly heated to 200 to 300 ° C., and the raw material in a room temperature state is formed at a forming speed of 50 mm / sec and a pressing force of 6 mm.
Molded product 1 shown in Fig. 1 after warm forging at 00t
Was manufactured by coining. The coined groove 2 had a depth of 0.5 to 1 mm, and the molded product did not warp. The mounting hole 3 was drilled before the groove 2 was forged. (Example 2) Extruded plate material of AZ31 alloy (wall thickness 2 m
m) is used to cut a raw material having the same shape as that of Example 1 by a mold heated to 200 to 250 ° C.
Warm forging was performed under the same conditions as above. The depth of the coined groove 2 was 0.5 to 1 mm, but the molded product did not warp. (Comparative Example) Under the same conditions as in Example 1 and Example 2, except that
Warm forging was performed with the material preheated or the mold temperature was different by 260 ° C. Molded products have a wall thickness of 2 mm, 3
A warp occurred in mm.

Table 1 shows the relationship between forging forming conditions and warpage. In the table, a circle indicates that there is no warp, a triangle indicates that warpage has occurred, and a cross indicates a large degree. This indicates that warpage has occurred.

From Table 1, when the material of the magnesium alloy plate material is kept at room temperature and warm forged by a die heated to 200 ° C. or higher, the molded product 1 does not have a change in the thickness of the material. It can be seen that no warpage has occurred. But,
It was confirmed that when the mold heating temperature was 200 ° C. or lower, the molded product 1 was warped. Meanwhile, the material is 120
In the case of forging using a mold heated to 160 to 230 ° C in a state of being heated to 360 ° C, all of the molded products 1
It was confirmed that a large amount of warpage occurred.

[0021]

As described above, according to the present invention,
It is possible to inexpensively manufacture a lightweight, high-quality thin-walled molded product made of a magnesium alloy without deformation such as warpage. In particular,
INDUSTRIAL APPLICABILITY The method of the present invention is suitable for performing forging forming such as coining and embossing on a magnesium alloy plate material having a thickness of 5 mm or less. Table 1

[Brief description of drawings]

FIG. 1 is a plan view of a thin-walled molded product that is forged by the method of the present invention.

FIG. 2 is a sectional view taken along line 2-2 of FIG.

FIG. 3 is a sectional view taken along line 3-3 of FIG.

[Explanation of symbols]

1 molded product 2 grooves 3 mounting holes

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) C22F 1/00 691 C22F 1/00 691B 1/06 1/06 (71) Applicant 501133236 Tatsuhiko Aizawa Tokyo Komae 2-5-5 Iwata, Ichi, Ichi, Japan (72) Masayoshi Kitagawa, 12-12 Kitahorie, Nishi-ku, Osaka-shi, Osaka Prefecture Kurimoto Iron Works Co., Ltd. (72) Inventor Yoshisada Kitahorie, Nishi-ku, Osaka-shi, Osaka 1-12-19 Kurimoto Iron Works Co., Ltd. (72) Inventor Keiichi Maekawa 1-12-19 Kitahorie Nishi-ku, Osaka City, Osaka Prefecture Inventor Kurimoto Iron Works Co., Ltd. (72) Nobuo Kitada Nishi-ku, Osaka City, Osaka Prefecture Kitahorie 1-12-19 Kurimoto Iron Works Co., Ltd. (72) Inventor Hisashi Mori 2-838 Hikarimachi, Kokubunji, Tokyo Metropolitan Institute of Railway Technology (72) Inventor Taro Tsujimura Tokyo 2-8-38, Mitsumachi, Kokubunji-shi 38-38, Institute of Public Railways, Foundation (72) Inventor Kenji Higashi 3-4-9, Teraikedai, Tomitabayashi, Osaka Prefecture (72) Tatsuhiko Aizawa, 2 Iwatokita, Komae-shi, Tokyo 5th-5th F-term (reference) 4E087 AA08 AA10 BA03 BA19 CA17 CB02 ED12 GA07

Claims (6)

[Claims] 1. Forming of a magnesium alloy plate material, which is characterized in that a material made of a magnesium alloy plate material is not preheated, only a die is preheated, and the material is warm forged by the heated die. Processing method. 2. The thickness of the magnesium alloy plate material is 5
The method for forming a magnesium alloy sheet material according to claim 1, wherein the sheet material is less than or equal to mm. 3. The mold temperature in the warm forging is 2
The temperature is from 00 to 350 ° C. 3.
A method for forming and processing a magnesium alloy plate material as described. 4. The method for forming a magnesium alloy sheet material according to claim 1, 2 or 3, wherein a forming speed in the warm forging forming step is 10 to 200 mm / sec. 5. The method for forming a magnesium alloy plate material according to claim 1, wherein the warm forging is a coining process. 6. The method of forming a magnesium alloy sheet material according to claim 5, wherein the processing depth in the coining processing is 50% or less of the thickness of the material.