JPS6255459B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a forging method, and particularly to a forging method that improves the metal structure of the central surface of a forged material.

Conventionally, for forging disks, etc., the main forging methods were flat upsetting, cap upsetting, etc., but especially when forging high-alloy steel disks, the forging around the center surface of the disk was insufficient, resulting in metal structure problems. However, it had the disadvantage that its mechanical properties were much inferior compared to other peripheral parts.

This invention solves the conventional drawbacks at once by combining the conventional upsetting forging method and the forging method of the present invention, resulting in a uniform and good structure over the entire area of the to-be-forged product and excellent mechanical properties. It is a method for forging a product, the gist of which is to forge the end corners in one or two stages.
This is a forging method in which the outer periphery of the material to be forged is forged using a step-cut flat anvil, and then the raised build-up portion in the center is alternately forged to achieve a predetermined thickness.

Hereinafter, the present invention will be described in detail based on drawings showing one example of implementation.

FIG. 1 is a perspective view showing a state in which a first forged part F ₁ is being forged with an upper anvil 2 while rotating a forged material M placed on a rotary anvil 1.

After the first forged part F ₁ has been forged to a predetermined thickness in the circumferential direction, the process moves to the forging shown in FIG. 2. In this case, only the second forged part F ₂ is actively Generally, forging is performed in the circumferential direction using the upper anvil 2. When the forging shown in FIG. 2 is completed, the central built-up portion disappears, and therefore the first forged portion F ₁ and the second forged portion F ₂ become planar. After the forging of the second forged part _F2 is completed, the first forged part is again forged, and by alternately forging in this way, a forged material of a predetermined thickness is finally obtained. .

Figure 3 is a drawing showing the shape of the upper anvil, a
is a perspective view, b is a front view, and c is a side view. In figures b and c, 21 and 22 are cut portions.

Although the general forging method of this invention is as described above, in order to obtain a high-quality forged product, it is desirable to adopt the following forging conditions.

[Forging method]

A. As shown in FIG. 1, the first forged portion _F1 is rotary forged to form a second forged portion _F2 having a convex portion in the center. The reason why this convex portion F ₂ was formed is to force down only this portion.

B Next, as shown in Fig. 2, set the upper anvil 2 so that the corner part 22 of the upper anvil 2 is in contact with the center C of the convex part of the material to be forged M, and place the material to be forged 11 times against the upper anvil 2.
It rotates at an angle of within 45 degrees per turn, and this convex part
Flatten F ₂ .

If the rotation angle is increased to 45° or more, the contact area between the forged material M and the upper anvil 2 will increase.
This is because a localized low-forging area occurs in the surface layer of the forged material.

C. Repeat steps A and B above, applying pressure alternately to the top and bottom surfaces, until the total reduction amount is 20% or more for both the top and bottom surfaces.

The reason why the total reduction amount is set to 20% or more on one side is based on the facts from various experiments, as shown in FIG. That is, the dendrite structure is not destroyed unless the logarithmic compressive strain (ε) is 0.6 or more.

D Amount of upsetting for flat upsetting etc./Amount of upsetting for this forging method = 2.3
~3.6. This forging method has a good forging effect, especially on the central surface layer of the disc. Therefore, in order to make the metal structure and mechanical properties uniform throughout the disc, ordinary flat upsetting and cap upsetting methods are used. It is necessary to balance the amount of upsetting with the amount of upsetting in the main forging method, and with this in mind,
The above values were set. FIG. 5 shows the relationship between logarithmic compression strain and this ratio. The reason for this value is
If this ratio is less than 2.3 or more than 3.6,
Since only one of the center surface strain or the center strain becomes large, both the metallographic structure and the mechanical properties become non-uniform.

On the other hand, when this ratio is set to 2.3 to 3.6, almost the same plastic strain exists from the center surface to the center, and the metal structure and mechanical properties become homogeneous.

Example material: Ni-based super heat-resistant alloy Original dimensions: 900φ x 160mm Product dimensions: 850φ x 120mm Reduction force: 3500t Reduction amount: 20mm/one rotation Rotation angle: 22.5°/one time Upsetting amount for flat upsetting, etc./piece Upsetting amount of forging method = 2.6
Microstructure in the center of the surface The metal structure in each part of the forged product was homogeneous, and the mechanical properties were also uniform.

The present invention is as described above, and according to the present invention, the metal structure is homogenized, especially the metal structure in the central part of the disk material is homogenized, and grain flow lines flow uniformly from the periphery, thereby improving mechanical properties. has also been further improved, and its industrial value is significant.

[Brief explanation of the drawing]

FIG. 1 is a perspective view showing an example of the implementation of this invention;
Fig. 2 is a perspective view showing a state in which the central part is forged in an example of the implementation of the present invention, Fig. 3 a is a perspective view of the anvil, b is a front view of the anvil, and c is a side view of the anvil. It is. FIG. 4 is a graph showing the relationship between the amount of reduction on one side (%) and the logarithmic compressive strain (ε), where ε=
The 0.6 dotted line indicates the minimum amount of strain necessary to destroy the dendrite structure, below which it is not destroyed, and above it is destroyed. FIG. 5 is a graph showing the relationship between the amount of upsetting such as flat upsetting/the amount of upsetting in the present forging method and logarithmic compressive strain (ε), where a indicates the center strain and b indicates the center surface strain. 1... Rotating anvil, 2... Upper anvil, 21, 22...
...Cut part, _F1 ...First forged part, _F2 ...Second forged part, M...Forged material, C...Center of convex part of M, P
...pressure force.

Claims (1)

[Claims] 1. Forging the outer periphery of the material to be forged using a flat anvil with one or two steps cut at the end corners, and then forging the raised overlay part in the center, alternately, to achieve the specified thickness. A forging method characterized by making it thick.