JPH07227639A - Manufacture of forged product - Google Patents

Abstract

PURPOSE:To obtain a product having sufficient draft and the same strength as a forged product and smooth and good surface quality peculiar to the forged product by casting a non-similar shaped preform-corresponding to the forged product as the finish shape and forging this preform. CONSTITUTION:A disk preform M has a hub fitting part H in the recessed condition in the back side at the center part. Further, a spoke part S having recessed part A and projected part B is provided with the outer periphery of the hub fitting part H and further, an annular inner rim joining part J projected in the back side is provided with the outer periphery of the spoke part S. An outer rim R is provided with the outer periphery of the inner rim joining part J and this disk preform in the whole body is formed as non-similar shape to the disk D as the finish shape. Then, a hole C for obtaining material flow at the time of casting is arranged at the center part of the hub fitting part H. The disk preform M is made to be the shape, by which draft at the time of forging can be obtd. at >=15%.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a forged product in which a material formed by casting is forged into a final shape.

[0002]

2. Description of the Related Art As a method of manufacturing a forged product of this type, there is one disclosed in, for example, Japanese Patent Laid-Open No. 1432031/1992.

In the manufacturing method disclosed in the above publication, first, a disk portion material is manufactured by casting, and at this time, the disk portion material is formed into a shape similar to the final product (disk member). After that, the disc member of the vehicle wheel is obtained by forging the disc portion material.

As described above, the disc portion material is produced by casting, and the disc portion material is forged to produce the disc member, so that the forging process is simplified.

[0005]

However, in the above-described conventional method for manufacturing a vehicle wheel, since the disk portion material formed by casting has a shape similar to the final product, the workability at the time of forging is high. It becomes smaller, and the strength effect due to forging (for example, the effect of fine fragmentation of resinous crystals generated during solidification in casting and the effect of generation of grain flows), and smoothness which is one of the characteristics of forged products There is a problem that a glossy surface cannot be obtained, and it has been a problem to solve such a problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and is a forged product obtained by the steps of casting and forging, which is capable of improving strength and surface quality. It is intended to provide a manufacturing method.

[0007]

According to a first aspect of the present invention, there is provided a method for manufacturing a forged product, which comprises forming a material formed by casting into a final shape by forging. In the method for manufacturing a forged product according to claim 1, a forged product is formed by casting a material having a shape not approximate to that of the product by forging, and forging the material. A disc for a road wheel, the disc material formed by casting has a hub attachment part in the center and spokes with irregularities on the outer periphery of the hub attachment part. Forging the thickness of the hub attachment part With more than 130% of the later thickness,
The thickness of the bottom of the recess is three times or more the thickness after forging, and the height of the protrusion is one-third or less of the height after forging, and claim 3 In the method for manufacturing a forged product according to Item 2, the outer rim is integrally formed on the disc. Further, in the method for manufacturing a forged product according to Claim 1, the forged product has a cross section H. It has a shape and the thickness of the bottom of the recess of the material formed by casting is 130% or more of the thickness after forging, and the height of the protrusion is half or less of the height after forging. In addition, in the method for manufacturing a forged product according to claim 1, the forged product has a rectangular cross section, and the thickness of the material formed by casting is It is configured to mold a forged product by setting it to 130% or more. And a means for solving the problems of the formation.

The non-approximate shape of the material in the above-mentioned structure is a shape corresponding to the final shape of the forged product, and does not mean a completely different shape from the forged product.

[0009]

In the method for manufacturing a forged product according to the present invention,
According to claim 1, the material formed by casting has a shape that is not approximate to the forged product that is the final shape, and as claimed in claim 2, the thickness of the hub attachment portion of the disc material and the thickness of the bottom portion of the recessed portion of the spoke portion. By setting the heights of the convex portions in the spoke portions and the spoke portions, the degree of workability at the time of forging the disc material becomes sufficient, and the strength and the surface quality corresponding thereto can be obtained.

Further, in the method for manufacturing a forged product according to claim 3 of the present invention, by forming the outer rim integrally with the disk in the manufacturing method according to claim 2, the road wheel is required to have the highest strength and The outer rim, which is the appearance of the wheel, also has strength and surface quality obtained by forging.

Further, in the method for manufacturing a forged product according to the present invention, as the fourth aspect, the thickness of the bottom of the concave portion and the height of the convex portion in the material having the H-shaped cross section are set. By setting the thickness of the material forming the shape, the workability at the time of forging the material becomes sufficient, and the strength and surface quality corresponding thereto can be obtained.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a method for manufacturing a forged product according to claims 1 to 3 of the present invention. Disc material M (Fig. 1a) and disc D formed by forging the disc material M (Fig. 1a).
It is a figure which shows b).

The disk material M is made of, for example, an aluminum alloy, and has a hub mounting portion H in a recessed state on the back side (lower side in FIG. 1) in the center and a hub mounting portion H.
Has a spoke portion S having a concave portion A and a convex portion B on the outer periphery thereof, and further has an annular inner rim joint portion J projecting to the back side on the outer periphery of the spoke portion S and the outer periphery of the inner rim joint portion J. Has an outer rim R and is formed in a non-approximate shape to the disk D which is the final shape as a whole. In addition, a hole C is provided in the center of the hub mounting portion H for obtaining the flow of material during forging.

Here, FIG. 4 shows an aluminum alloy (60
61) is a graph showing the change in tensile strength and proof stress according to the rolling reduction (working degree) of the cast product (black circle) and the cast (forged) T6 treated product (white circle). is there. Further, FIG. 5 shows a molded product only by casting (black circle).
3 is a graph showing a change in elongation of a molded product (white circle) produced by casting and forging with a reduction rate.

That is, in order to obtain the strength equivalent to forging using A6061 as a material in the method of forging after casting, 15
% Or more processing is required. Further, the disc D requires strength in the order of the outer rim R, the spoke portion S, and the hub mounting portion H, and in order to cope with this, the outer rim R and the spoke portion S have a workability of 15% or more. It is desirable to obtain

Therefore, the disk material M is
The thickness t1 of the hub mounting portion H formed by casting is set to 130% or more of the thickness t2 after forging, and the thickness t3 of the bottom portion of the recess A is formed so as to obtain a workability of 5% or more.
Is 3 times or more the thickness t4 after forging, and as shown in FIG. 2, the height h1 of the convex portion B is 3 times the height h2 after forging.
It is less than one-third.

Further, at the inner rim joint J, a flow of material occurs from both sides with respect to the projecting portion during forging, which causes forging defects such as cracks P as shown in FIG. Therefore, the material distribution is the same as that after forging in terms of volume. In the outer rim R, a part of the material flows to the outside of the forging die to form the burrs Q, so that it is possible to set the dimensions with a margin.

Then, in the method for manufacturing a forged product of the present invention,
The disc material M formed by casting into the above-mentioned shape is forged into a disc material M
The degree of workability during forging is 15% or more, sufficient strength can be obtained by forging, and a smooth and glossy surface, which is one of the characteristics of forged products, can be obtained.

The disc D has an outer rim R.
Is integrally molded, and the outer rim R, which requires the most strength in the road wheel and has the appearance of the wheel, is in a state where sufficient strength and good surface quality are obtained by forging.

The disc D after forging is later processed by cutting or the like on the back surface, and the concave portion A becomes an air hole by removing the bottom portion thereof. Further, the road wheel including the disc D of the present embodiment is called a two-piece type including a disc D integrally having an outer rim R and a separately manufactured inner rim (not shown),
This is completed by joining the inner rim to the inner rim joint J of the disc D by welding.

FIG. 6 is a view for explaining an embodiment of a method for manufacturing a forged product according to claim 4 of the present invention, which is a forged product having an H-shaped cross section, which is used for a vehicle suspension. As an example, the link material M1 (a, b) formed by casting and the link material M
Transbar link T formed by forging 1
(C, d) are shown.

The link material M1 is made of aluminum alloy, and the link portion between the three supporting portions 1 to 3 has an H-shaped cross section due to the web (recess) 4 and the ribs (convex portions) 5 and 5 on both sides thereof. The overall shape is a non-approximate shape to the final shape of the transbar link T.

Here, as described in the embodiment of the disk, it is desirable to obtain a workability of 15% or more in order to obtain the strength equivalent to forging in the method of forging after casting.

Therefore, in the link material M1, the thickness t5 of the web 4 which is the thickness of the bottom portion of the recess is 1 after the forging thickness t6.
The height (height from the web surface) h3 of the rib 5 which is the height of the convex portion is set to 30% or more and is half or less of the height t4 after forging. As a result, the link material M1
The transbar link T formed by forging is obtained with a sufficient workability of 15% or more.

FIG. 7 is a diagram for explaining an embodiment of a method for manufacturing a forged product according to claim 5 of the present invention, in which an upper arm used for an automobile suspension is used as a forged product having a rectangular cross section. Take it as an example.

The upper arm U has three supporting portions 11 to 11.
The portion between 13 has a rectangular cross section, and the thickness of the rectangular section of the material (not shown) formed by casting is 130% or more of the thickness t7 after forging, and the material is forged. It is molded by performing. As a result, the upper arm U has a sufficient workability of 15% or more.

[0027]

As described above, according to the method for manufacturing a forged product according to claims 1 and 2 of the present invention, the forged product or the road wheel disc obtained by the steps of casting and forging is forged. In this case, since a sufficient degree of processing can be obtained, it is possible to obtain a sufficient strength equivalent to that of forging, and it is possible to obtain a smooth and glossy good surface quality peculiar to forging.

According to the method for manufacturing a forged product according to claim 3 of the present invention, in addition to the above-mentioned effects, the outer rim R which requires the most strength in the road wheel and has the appearance of the wheel is sufficient. It is possible to obtain strength and good surface quality.

Further, according to the method for manufacturing a forged product according to claims 4 and 5 of the present invention, a forged product having an H-shaped cross section obtained by the steps of casting and forging, and a rectangular cross section obtained by the same process. In the forged product, it is possible to obtain a sufficient degree of workability during forging, to obtain strength equivalent to that of forging, and to obtain good surface quality.

[Brief description of drawings]

FIG. 1 is a cross-sectional view illustrating a disk material (a) after casting and a disk (b) after forging in a method for manufacturing a forged product according to claims 1 to 3 of the present invention.

FIG. 2 is a sectional view (a) of the convex portion based on the line EE in FIG. 1a and a sectional view (b) of the convex portion based on the line FF in FIG. 1b.

FIG. 3 is a sectional view illustrating a forging defect in an inner rim joint portion.

FIG. 4 is a graph showing changes in tensile strength and proof stress of a forged only molded product and a cast forged product with a reduction rate.

FIG. 5 is a graph showing a change in elongation with a reduction rate of a forged only molded product and a cast forged product.

FIG. 6 is a side view (a) showing the link material after casting in the method for manufacturing a forged product according to claim 4 of the present invention, a cross-sectional view (b) taken along line XX in FIG. It is the side view (c) which shows a trans bar link, and sectional drawing (d) based on the XX line in Drawing c.

FIG. 7 is a perspective view illustrating an upper arm after forging in the method for manufacturing a forged product according to claim 5 of the present invention.

[Explanation of symbols]

 A concave part B convex part D disk (forged product) H hub mounting part M disk material M1 link material R outer rim S spoke part T transver link (forged product) U upper arm (forged product) 4 web (recessed part) 5 rib ( Convex)

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Kiyoshi Takagi 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Motor Co., Ltd.

Claims (5)

[Claims] 1. A method for manufacturing a forged product in which a material formed by casting is formed into a final shape by forging, and a material having a non-approximate shape to the final shape of the forged product is formed by casting and the material is forged. A method of manufacturing a forged product, which comprises forming the forged product by doing so. 2. The method for manufacturing a forged product according to claim 1, wherein the forged product is a disc for a road wheel, and the disc material formed by casting has a hub mounting portion in the center and an outer periphery of the hub mounting portion. It has a spoke part with unevenness, and the thickness of the hub mounting part is 1 of the thickness after forging.
It is characterized in that the thickness of the bottom of the recess is set to 30% or more, the thickness of the bottom of the recess is set to be three times or more the thickness after forging, and the height of the projection is set to one third or less of the height after forging. Manufacturing method of forged products. 3. The method for manufacturing a forged product according to claim 2, wherein an outer rim is integrally formed on the disc. 4. The method for manufacturing a forged product according to claim 1, wherein the forged product has an H-shaped cross section, and the thickness of the bottom of the recess of the material formed by casting is 130% of the thickness after forging. In addition to the above, the height of the convex portion is ½ of the height after forging.
A method for manufacturing a forged product characterized by the following. 5. The method for manufacturing a forged product according to claim 1, wherein the forged product has a rectangular cross section, and the thickness of the material formed by casting is 130% or more after the forging. Forged product manufacturing method.