JPH02133132A - Hot precision forging method - Google Patents

Abstract

PURPOSE:To execute forming of a forged part with high precision by supporting a forming die by a supporting member whose contact surface is a convex curved surface and giving positively and adjustably a bending moment standing against an elastic deforming generated in the die by external force. CONSTITUTION:Forging use press loads F, F are loaded to the upper die 1 and the lower die 1' and a forged part 9 is brought to hot precision forging by impressions 4, 4'. Subsequently, jacks 7, 7' interposed between each arm 2, 2' provided on the upper and the lower dies 1, 1' are driven by a hydraulic pump 8, and separting force in the direction as indicated with an arrow (f) is operated. The upper and the lower dies 1, 1' are subjected to a concave are-like elastic deformation by the forging loads F, F of the upper and the lower dies 1, 1' along convex curved surfaces 5, 5' of the contact surface with a supporting base 3. Next, bending moments (m), (m) by which each center part 10, 10' of both the dies 1, 1' in the direction opposite thereto are bent to each adjacent covex arc shape are generated, the deformation quantum of the concave arc shape is suppressed, and a dimensional tolerance of thickness to the forged part 9 becomes small. Also, by adjusting variably the bending moment, a thickness control can also be executed. In such a way, the forged part 9 having the same accuracy can always be manufactured.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention is a hot precision forging process in which metal materials such as aluminum alloys and steel are press-forged into a final product shape that does not require machining using a forming die. The present invention relates to an improved means for improving the thickness accuracy of a forged product and making it possible to proactively control the thickness.

(Prior art) As is known, precision forgings made of aluminum alloy materials are widely used as various parts for aircraft, and these are all forged and installed in actual aircraft with minimal machining. It is often done.

At this time, in order to reduce the amount of machining required after forging, hot forging using a forming die is used to improve the dimensional accuracy of each part, while also controlling the metal flow to obtain the necessary material properties. It is customary. For general information on hot forging technology for aluminum alloy materials and recent technological trends, please refer to "Plasticity and Processing J Vol.
23, No, 253 (19822), P, 129-P,
136 [Hot forging technology for aluminum alloys] (
The characteristics and technical points of hot precision forging technology are also described in Reference I), “Plasticity and Processing J Vol. 29, N.
o, 271 (1983-8), P, 823-P, 82
9, ``Hot Precision Forging of Aluminum Alloys'' (as explained in the old literature), and both articles also show measures to improve product precision in these forging methods, limitations of current technology, etc. ing.

(Problems to be Solved by the Invention) Conventional precision forging means for aluminum alloy materials have the following problems. That is, Table 1 shown in the above-mentioned document I
The projected area of the forged product and the thickness tolerance in the forging direction are 1
+mn is shown for each forging content, and Figure 4 in Document H shows the relationship between the projected area and the minimum web thickness. The precision forging is in the range of 0.2 to 0.3M in terms of tolerance, and in response to this requirement, precision forged products with a large projected area are
The reality is that this cannot be achieved with forging as is, and finishing to specified tolerances is done by subsequent machining. In order to improve this situation, when producing a precision forged product with a large projected area, in order to accurately forge the web thickness of the forged product, the elastic deformation in the forming die is anticipated in advance, and the Means for die-sinking in a mold are also known, but this means has the disadvantage that thickness accuracy cannot be actively controlled during forging.

(Means for Solving the Problems) The present invention solves two problems in conventional precision forging, namely:
The web thickness of a forged product increases as the projected area increases, making it impossible to obtain a forged product that fits within a more precise dimensional tolerance, and also due to the die-sinking shape of the forming die and the surface pressure distribution during forging. This was done to solve the problem that the amount of deformation of the die is determined and therefore the thickness dimension of forged products cannot be controlled. This actively controls elastic deformation in the die during forging, making it possible to reliably and easily obtain the desired web thickness for forged products. During hot precision forging, a forged product in the final product shape is forged using a forming die at a required heating temperature, and the forming die is supported by a support member whose contact surface is a convex curved surface. , by positively applying a bending moment to the mold by an external force to counter the elastic deformation that occurs in the mold during pressure forging, and by adjusting the amount of bending, the required dimensional tolerance of the forged product can be achieved. The purpose is to enable control of the thickness of the bottom.

(Function) According to the above-mentioned technical means, in FIG. 1, the forging press loads F and F are respectively applied to the upper die 1 and the lower die 1', When performing hot precision forging of a forged product 9 having the desired final product shape using the impressions 4 and 4′ formed on each die surface of .1, if the projected area of the forged product 9 is large as it is, the forging Item 9
There is a difference in web thickness between the center and edges of the web. That is, due to the forging loads F and F, both the upper and lower dies 1 and 1° are elastically deformed in a concave arc shape, and the web thickness of the forged product 9 at the center is large and the web thickness at the peripheral edges is small. In the invention, each arm 2 provided at the upper and lower molds 1 and 1°
, the jack 7.7゛ inserted between 2 degrees is
As shown in FIG. As mentioned above, the lower mold 1
, 1゛The bending moment m, m of convex arc-shaped bending when the respective central parts 10゜10゛ of both molds 1 and 1' are close to each other is in the opposite direction to the concave arc-like elastic deformation due to forging loads F and F of 1゛. In order to suppress the amount of concave arc-shaped deformation by causing
The dimensional tolerance of the thickness of the forged product 9 can be made smaller than before. Furthermore, by actively applying this bending moment m and variably adjusting the bending moment m by changing the amount of bending, it is also possible to control the thickness during forging. That is, the purpose forged product 9
By adjusting the amount of bending according to the size of the web, the thickness of the web, and the magnitude of the forging load, a forged product 9 with the same precision can be manufactured at all times.

(Example) A suitable example of the method of the present invention will be described with reference to FIGS. 1 to 4.

In order to make the method of the present invention possible, a means for suppressing and controlling elastic deformation during forging in a precision forging mold by an external force, that is, a means for applying a bending moment within the plane of the mold is required. , it is necessary to provide a guide means that can be controlled during forging, and it is also necessary to provide a guide means that can easily apply a bending moment. Therefore, in the embodiment, as illustrated in FIGS. FIG. 1 shows only the lower mold side of the upper and lower mold apparatus, and FIG. 2 shows the entire upper and lower mold apparatus. A target impression 4' corresponding to the shape of the final product is engraved on the upper surface, and when the lower mold 1'' is rotated, arms 2° and 2'' are provided in a protruding manner at symmetrical positions on both the left and right sides. As shown in the figure, the arms 2, 2' are bent by applying a force f in the direction of the arrow to create a bending moment m.
The lower mold 1' is supported in contact with the upper surface of the support stand 3 which is a support member installed on the pedestal 6; The contact surface has a convex curved surface of 5 degrees with one of the contact surfaces being higher at the center so that the bending moment m can be easily applied. FIG. 2 shows the assembled state of the upper and lower molds, which have the same structure as the lower mold 1 shown in FIG.
That is, an impression 4, an upper mold 1 having an arm 2.2, a support base 3 having a convex curved surface 5, a base 6 on which the support base 3 is installed, and both molds l.

Impressions 4 and 4' at 1° are arranged one above the other in a corresponding manner. At this time, hydraulic jacks 7.7 are interposed between the left and right arms 2, 2, which face each other vertically in parallel, as actuating members that apply a force f in the direction of the arrow. .7, and as shown by the arrow fr, the upper mold 1
By applying a separating force upwardly to the arms 2, 2 of the lower mold 1'' and downwardly to the arms 2', 2' of the lower mold 1'', bending moments m and m are respectively generated. By varying the drive oil pressure,
The bending moments m and m can be adjusted in size.

In addition, the forging loads F and F are applied to the pedestals 6 and 6' from both the molds 1 and 6 in the vertical direction as shown by the arrows. It is provided so that the load is applied to l'.

According to the upper and lower molding molds 1 and 1″ having the above-described configuration,
As shown in Fig. 2, by applying forging loads F and F from the upper and lower pedestals 6 and 6' sides, the metal material such as aluminum alloy material inserted between both molds 1.1 It will be compressed to 1.1" impression 4.4" and hot precision forged as a forged product 9 in the final product shape.
In the conventional method, as the forging loads F and F are applied, both the dies 1 and 1'' are elastically deformed in a concave arc shape, resulting in a size difference in the thickness of each web between the center and end portions of the forged product 9. When the projected area is large, it is difficult to maintain and form the web within a predetermined dimensional tolerance, requiring subsequent correction by machining, and it is of course impossible to adjust the web thickness during forging. At this time, in the present invention, both molds 1
Hydraulic jack 7 interposed between each arm 2, 2 of , 1.
．． 7 is load-driven by a hydraulic pump 8, and both arms 2.2
By separating the molds 1 and 1' in opposite directions, bending moments m and m are generated due to the separation force f in the direction of the arrow, and both molds 1 and 1' are elastically moved along the convex curved surfaces 5 and 5' with their supporting contact surfaces. deformation, and a convex arc-shaped deformation in the opposite direction to the concave arc-shaped deformation of both molds 1.l'' during forging as described above is obtained, and each center portion 10.10' of both molds 1, 1'' is mutually This bends the web so that it protrudes close to each other, and prevents the web thickness from increasing at the center.Therefore, it is possible to reliably obtain molding within the desired dimensional tolerance and with a value smaller than the conventional dimensional tolerance. In addition, by not only suppressing this bending moment but also actively applying it, and adjusting the bending moment in size, it is also possible to control the web thickness during forging. It is said that the accuracy of forged products depends only on the forming die, but according to the present invention, the deformation of the forming die can be freely controlled by external force, so the improved accuracy of forged products is a revolutionary advantage. However, by controlling the amount of bending according to the size and thickness of the intended forged product and the magnitude of the forging load, it is possible to always manufacture forged products with the same high precision.

In the embodiment, a structure using the hydraulic jack 7 and the hydraulic pump 8 was exemplified as a structure for applying the bending moment, but a drive mechanism other than rotation can be used. Furthermore, when applying the bending moment, it is also possible to apply the bending moment from four directions, as illustrated in FIG. That is, as shown in the figure, both molds 1
．． Arms 2a + 3a, 4a, and la are symmetrically formed at four symmetrical positions on the circumferential surface of lo, and the bending moment imparting force acting on each arm 1a to 4a at this time is the same for all. You can also
It is also possible to make all of them different, and it is sufficient to freely control them depending on the shape of the target cast product.
It is preferable to have a convex curved surface in the shape of a bun, with the center being higher than the periphery.

Also, molding mold 1. Convex curved surfaces 5, 5 on support base 3, 3 of lo
Instead of forming an angle between the two molds 1, 1'' and the supports 3, 3'' on a plane, as illustrated in FIG.
On the surface where ゜3゛ contacts, the convex curved surface 5.5 on the pedestal 6 side
In this case, an arm 2.2° may be provided on the circumferential side of the support base 3, and the same effect can be achieved by applying a separating force f.

Although not shown, it is of course equally effective to provide convex curved surfaces 5, 5' on both sides of the support base 3 that contact the pedestal 6 side.

(Effects of the Invention) According to the present invention, the drawbacks observed in conventional hot precision forging methods, namely, the web thickness of the forged product increases as the projected area increases, making it impossible to obtain a highly accurate forged product, Furthermore, the amount of die deformation is determined by the die sinking shape of the forming die and the surface pressure distribution during forging, which simultaneously eliminates the inability to control the dimensions of the forged product, and provides forged products with higher precision. This method is extremely advantageous in that it enables thickness control during forging and provides forged products with the same precision.

That is, by applying a bending moment to the forming die so as to cause convex arc-shaped deformation in the opposite direction to the concave arc-shaped elastic deformation that occurs in the same mold during forging, despite the increase in the projected area, This makes it possible to form forged products with higher precision, and by actively and adjustablely applying the bending moment, it is also possible to control the thickness at the same time, making it possible to perform hot precision forging of various metal materials including aluminum alloys. This is an excellent product as it opens up new horizons for the world.

[Brief explanation of the drawing]

Fig. 1 is a perspective view of the main parts of the molding die used in the method of the present invention, Fig. 2 is an overall perspective view of the same mold in the assembled state, and Fig. 3 (a
3(b) is a perspective view of the support base, and FIG. 4 is a perspective view of the same mold support variant. ■-Upper mold, 1゛-Lower mold, 2.2'-Arm, 3.3
゜Support stand, 4.4'-impression, 5.5', 5
a, 5a convex curved surface, 6,6'--pedestal, 7-hydraulic jack, 8-hydraulic pump, la, 2a, 3a, 4a-arm, 9-forged product, 10, 10'-one mold center Department. 2C Figure Figure

Claims (1)

[Claims] (1) During hot precision forging, in which a metal material such as an aluminum alloy is forged into a forged product in the final product shape using a forming die at a required heating temperature, the contact surface of the forming die is convex. Supported by a curved support member, and in the mold,
By positively applying a bending moment using an external force to counter the elastic deformation that occurs in the die during pressure forging, and adjusting the amount of bending, it is possible to control the thickness of the forged product within the required dimensional tolerance. A hot precision forging method characterized by: