JPH0455034A - Precision forging method - Google Patents

Abstract

PURPOSE:To effectively enhance the accuracy of a shape and to reduce the thickness of a forging by forming a half finished product with using a rough molding die, then molding the forging of the final product with using a finish molding die. CONSTITUTION:The rough molding die 4 consists of upper and lower dies 4a, 4b and side dies 4c, 4d. A recessed part 7 for forming the part corresponding to a rib is formed at the center of the lower die 4b and a recessed part 8 for molding a bulging part in correspondence to the recessed part 7 is formed to the upper die 4a. The half finished product 2 forged by this rough molding die 4 is formed with parts 2b, 2c corresponding to flanges at both ends of the part 2a corresponding to the web and is formed with the part 2d corresponding to the rib and the bulging part 2e at the center of the part 2a corresponding to the web. The forged product 3 having the flanges 3b, 3c at both ends of the web 3 and the rib 3d at the center of the web 3a is obtd. if this half finished product 2 is forged by using the finish molding die 9. The product is thus finished with good accuracy to the range of the industrially required higher accuracy without requiring machining.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a method for forging metal materials such as aluminum alloys and forging steel materials with ribs in the shape of the final product using a forming die that does not require machining. This relates to precision forging methods for forming products.

(Prior art) Generally, precision forged products made of metal materials such as aluminum alloys and forging steel materials are widely used as strength components in aircraft parts, ships, vehicles, electronic devices, etc. All of these are assembled into actual machines by forging or with minimal machining.

Conventionally, in order to reduce the amount of machining required after forging, a precision forging method using forming dies has been adopted, increasing the dimensional accuracy of each part and imparting the necessary material properties through forging (for example, Published, “Plasticity and Processing” ν
oL, 30, NQ 343 (August 1989) 11
14-1120 "Hot Precision Forging of Alloy Parts for Aircraft" (Reference 1)).

(Problem to be solved by the invention) By the way, the conventional technology has the following problems.

First, when a product having a rib a as shown in FIG. 4 is precision forged, a sink defect C occurs on the back surface of the rib. Therefore, a method has been adopted in which the intermediate product d shown in Fig. 5 is formed, and then the web thickness - is made 2 to 3 times thicker than the rib thickness t as shown in Fig. 6 to eliminate sink mark defects. However, the range of precision for precision forged products that is actually required industrially is that the thickness ratio (web thickness to web thickness) is 1:1. In response to this request, the projected area is large (and the web is large).

In the case of a product with complex ribs, the above requirements cannot be met by forging, so after the forging is completed, the back surface of the rib a is removed by machining as shown by the diagonal line e in Fig. 6, and a predetermined web is formed. There is a problem in that it has to be finished to the desired dimensions.

Therefore, when forging parts with a large projected area and complicated webs and ribs, in order to reduce the web thickness of such forged products, the finishing die f is discarded and used for ribs g, as shown in Figure 7. There is a method in which a concave portion is provided, and the sacrificial rib g formed by precision forging is removed by machining, as shown in FIG. However, even with this sacrificial rib method, mechanical finishing is indispensable, and as shown in FIG. 9, there are problems such as cutting the grain flow line (brain flow) k, which may lead to defects.

The present invention was made in view of the above-mentioned circumstances, and
The purpose of this is to be able to finish forged products with ribs with high precision within the range of precision required industrially without the need for machining, as well as to improve shape precision and thin walls without sacrificing productivity. The purpose of the present invention is to provide a precision forging method that can achieve the desired results.

(Means for Solving the Problems) In the present invention, the following technical measures were taken in order to achieve the above object.

That is, in the present invention, in a precision forging method in which a metal material such as an aluminum alloy or forging steel is formed into a forged product 3 having a final product-shaped rib 3d using a forming die 9, a roughening process used in an intermediate process is performed. A concave portion 8 is provided on the opposite surface of the concave portion 7 for forming the lip-equivalent portion of the molding die 4, a bulge portion 2e is formed on the back surface of the lip-equivalent portion 2d of the intermediate product 2, and the bulge portion 2e is formed in the molding die. It is characterized by being flattened by mold 9.

(Function) According to the present invention, in the intermediate step, the concave portion 8 of the rough molding die 4 forms the bulge portion 2e on the back surface of the rib-corresponding portion 2d of the intermediate product 2. And this intermediate product 2
The bulging portion 2e eliminates the negative pressure on the rear surface of the lip 3d during finishing processing using the finishing mold 9, and compensates for the sinkage caused by the metal flow toward the rib 3d, thereby preventing buckling of the rear surface of the lip 3d. As the mode is relaxed, the metal flow becomes smoother, and the back surface of the rib is finished flat and precisely.

(Example) Embodiments of the present invention will be described below based on the drawings.

In FIG. 1, 1 is a raw material, 2 is an intermediate product, and 3 is a finished forged product, which is made of aluminum alloy material.

The material 1 is in the shape of a rectangular plate, and is made into an intermediate product 2 by a rough forming die 4 shown in FIG. 2 in an intermediate step. That is, the rough molding die 4 consists of an upper die 4a, a lower die 4b, and a side die 4c + 4d, and the side ends of the upper and lower dies 4a, 4b are provided with recesses 5a, 5b, 6a for forming flange equivalent portions.
, 6b are formed, a recess 7 for forming a rib-equivalent part is formed in the center of the lower mold 4b, and a recess 8 for forming a bulge part is formed in the upper mold 4a corresponding to the recess 7, The concave portion 8 for forming the bulge portion is formed of a smooth curved surface.

The intermediate product 2 forged by this rough forming die 4 has flange-equivalent parts 2b, 2c at both ends of the web-equivalent part 2a.
is formed, and a rib equivalent portion 2d is formed in the center of the web equivalent portion 2a.
and a bulge 2e are formed.

FIG. 3 shows the finishing mold 9, with an upper mold 9a and a lower mold 9b.
, side molds 9e, 9d, and upper and lower molds 9a, 9b.
A flange forming recess 10a is formed between both ends of the side molds 9c and 9d.
, 10b are formed above and below, a rib forming recess 11 is formed in the center of the lower mold 9b, and the web forming surface 12 of the upper mold 9a is flat.

When the intermediate product 2 is finish-forged using the finish-forming die 9, as shown in FIG.
A forged product 3 having the following properties is obtained. In this finish forging process, the bulging part 2e of the intermediate product 2 does not form a negative pressure part on the back surface of the rib 3d, and compensates for the sinkage caused by the metal flow toward the rib 3d, so that the buckling of the rib back surface As the mode is relaxed, the metal flow becomes smooth, and the back surface of the rib can be finished flat and precisely without sink marks, wrinkles, or scratches. Then, the rib thickness t and the web thickness are finished to be the same dimension, and the thickness can be reduced.

The present invention is not limited to the above embodiments, but can be applied to precision forging of parts with large projected areas and complicated webs and ribs.

(Effects of the Invention) As described above, the present invention provides precision forging in which a metal material such as an aluminum alloy or forging steel is formed into a forged product 3 having ribs 3d in the shape of a final product using a forming die 9. In the method, a concave part 8 is provided on the opposite surface of the concave part 7 for forming the rib-equivalent part of the rough molding die 4 used in the intermediate process, and a bulge part 2e is formed on the back surface of the rib-equivalent part 2d of the intermediate product 2. Since the bulging portion 2e is flattened by the forming mold 9, it is possible to achieve the precision within the industrially required range (web thickness to web thickness = 1:1) without requiring machining. ), and precision forging of various forging materials including aluminum alloys can be carried out efficiently without sacrificing productivity, and it is possible to achieve more precise shapes and thinner walls. be.

[Brief explanation of the drawing]

1 to 3 are detailed explanatory diagrams of the present invention, and FIG.
) to (C) are perspective views of the raw material, intermediate products, and forged products, Figure 2 is an exploded perspective view of the rough molding die in the intermediate process, Figure 3 is an exploded perspective view of the finishing mold, and Figure 4. - Figure 9 is an explanatory diagram of the prior art, Figure 4 is a cross-sectional diagram for explaining defects in forged products,
Fig. 5 is a cross-sectional view showing the shape of the intermediate product, Fig. 6 is a cross-sectional view of the forged product, Fig. 7 is a cross-sectional view showing the schematic configuration of the finishing mold, Fig. 8 is a cross-sectional view of the forged product, and Fig. 8 is a cross-sectional view of the forged product. FIG. 9 is an enlarged view showing grain flow lines in section A of FIG. 8. 2...Intermediate product, 2d...Rib equivalent part, 2e...
Swelling portion, 3... Forged product, 3d... Rib, 4...
Rough molding mold, 7... Concavity for forming rib-equivalent portion, 8.
...Concave portion, 9...Molding mold.

Claims (1)

[Claims] (1) In the precision forging method in which a metal material such as aluminum alloy or forging steel is formed into a forged product (3) having ribs (3d) in the shape of the final product using a forming die (9), an intermediate process is performed. A concave part (8) is provided on the surface opposite to the concave part (7) for forming the rib equivalent part of the rough molding die (4) used in the process, and a bulge part ( 2e) and flattening the bulged portion (2e) using a molding die (9).