JPS61147938A - Closed incrimental forging method - Google Patents

Abstract

PURPOSE:To form large-sized parts having intricate shapes by closed forging under the forming load under which the under fill is less produced by molding a blank material for rough molding with the parts where the under fill is liable to arise as a relief part then molding the relief part. CONSTITUTION:The blank material is roughly molded in a rough sectional molding stage 2 and is the successively molded in the 1st and 2nd molding stages 3, 4 where lower dies 5a, 5b and the outside circumferences of punches 6a, 6b fit tightly to each other. The punch 6a provided with the relief part 7 in the part where the under fill is liable to arise is used in the 1st stage 3 and the punch 6b provided with the molding part 9 corresponding to the relief part 7 is used in the stage 4. The area of the molding part 9 is made larger than the area of the relief part 7. The material moved to the part 7 in the 1st molding stage 3 is thereby molded in the part 9 in the 2nd molding stage to pack said part with the material. The quantity of the material moving into the relief part 8 is slight.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a closed incremental forging process.

Conventional technologyForged products with complex shapes, such as track links, require multiple processes in normal die forging, such as pasta, blocker,
The material must be forged into parts through a process such as a finisher, and the mold must be filled with the material by producing a large number of holes to perform the forging process. Therefore, this normal forging method is not preferred from the viewpoint of resource and energy saving.

Therefore, closed forging, which does not produce any particles, can be considered, but so far it has only been applied to small parts with simple shapes of α1-2.

Problems to be Solved by the Invention When the conventional closed forging method is used to mold large parts with complex shapes such as trunk links, it is difficult to fill the metal with material, making it difficult to obtain a satisfactory molded product. , the forming load becomes large and a very large press is required.

Ninth Means and Effects for Solving the Problems The present invention has been made in view of the above-mentioned problems, and includes a plurality of forming steps using a punch in which the outer part is tightly fitted into the lower plate, and the first forming step is In the step, the molded product is molded using a bottom-shaped mold that allows for relief of the parts that are prone to underfilling, and in the next molding process, the parts that correspond to the parts that were molded in the previous molding process are molded using a relief mold. Using the fluidity of the material, the material is moved to the part where there was a lack of fill in the previous molding process, and in the next forming process, the part where this material moved is molded to eliminate the lack of fill. Make sure to fill the raw part of the potato with the ingredients.

EXAMPLE FIGS. 1 to 3 show an embodiment of the closed incremental forging method according to the present invention. 1 ton of material - cross-section rough forming process 2
The material is roughly formed in the first and second forming steps 3 and 4.
Formed in stages.

In both the first and second molding steps 3.4, the lower mold 5a is used.

5b, and punches 6a and 6b whose outer parts fit closely into the lower molds 5a and 54. In the first forming step 3, relief parts 7t- The setup uses nine punch bats. In addition, in the second forming process 4, the first
A punch 6b is used which is provided with a relief portion 8 in a portion corresponding to the molding portion in the molding step 3. In this case, the area of the forming part 9 of the punch 6b used in the second forming process 4 is larger than the area of the relief part 7 of the punch 6a used in the first forming process 3. Note that the relief portions 7 and 8 refer to the portions created by cutting out the forming surface of the punch in the closed forging method to create a space.

In the first molding step 3, when molding is performed using the lower mold 5a and the punch 6a, the material accumulated in the molding section formed by both molds is moved to the relief section 7.

Next, in the second molding step 4, the part released in the first molding step 3 is molded in the molding part 9 of the lower mold 5b and punch 6b, and the material of this part is filled and molded. . The remaining material at this time is moved to the relief part 8 of this punch 6b, but the amount is small.

If necessary after this second molding step 4, a punch provided with a similar relief portion is used to perform molding in a plurality of subsequent molding steps, and a sizing step is included in the final step.

In order to investigate the significance of the forging method of the present invention for track links, a comparison was made between normal closed forging and closed incremental forging, and the following effects were revealed.

(1) In terms of moldability, FIG. 4 shows a molded product 10 produced by the method of the present invention, and FIGS. 5 to 7 show v-v, vx- of the molded product 10 shown in FIG.
w, each cross-sectional view along the line ■-■ is shown.

Moreover, FIG. 8 shows a molded product 9 made by the usual closed forging method,
Figures 9 to 11 are shown in Figure 8.
olK-i, X-X,! Each cross section along the I-XI line is shown.

Both molded products 10. Comparatively, in the case of the method of the present invention, in the first forming process 3, the material moves to the relief part 7 provided in the part where underfilling is likely to occur, so in the second forming process 4, the material moves It is easy to fill up and there is no lack of flesh.

On the other hand, in the normal closed forging method, as is clear from the cross-sectional views of each part shown in FIGS.
b, IIC, Ild' occurred.

(2) Concerning the forming load, normal closed forging attempts to create a completely sealed state and fill the room by increasing internal pressure, so a forming load that is more than twice that of conventional die forging is required, and even then, As shown in FIGS. 9 to 11, underfilling occurs. If it is attempted to prevent the underfilling at the 9th corner from occurring, the forming load at the end of the stroke of the punch becomes extremely large.

On the other hand, in the forging method according to the present invention, the punch is not completely sealed by providing a relief, but the fluidity of the material is used to fill the material as it moves. It was possible to form with less than half the forming load of closed forging without causing any underfilling. FIG. 12 shows the forming loads for each of the forging methods described above, in which A shows the die forging method, B shows the normal closed forging method, and C shows the method of the present invention.

(3) Regarding weight control of the material: Normal hermetic forging creates a completely sealed state, so strict weight control is required.
Mold damage may occur due to lack of thickness or sudden increase in mold surface pressure.

On the other hand, in the method of the present invention, by providing a relief part in the punch, a completely sealed state is not created during each molding process, making it easier to control the weight of the material, and preventing the mold from rapidly increasing surface pressure. It is possible to eliminate mold damage.

Although the above embodiment of the present invention shows an example in which the relief part is provided on the punch side, it may be provided on the lower plate side, or it may be provided on both the lower mold and the punch to obtain the same effect. be able to.

Effects of the Invention According to the present invention, it is possible to carry out closed forging on large parts such as trunk links with a smaller forming load than in the usual closed forging method, without causing any underfilling.

[Brief explanation of the drawing]

Figure 1 is a detailed explanatory diagram of the present invention, Figure 2 is l-H of Figure 1.
3 is a sectional view taken along line 1 in FIG. 1, FIG. 4 is a perspective view of a track link formed by the method of the present invention, FIGS. Figure 7 shows v-v in Figure 4, ■
8 is a perspective view of a track link formed by a normal closed forging method, and 9, 10, and 1I are sectional views taken along lines -■ and ■-■. i. A cross-sectional view taken along lines X-X and M-1, and FIG. 12 are diagrams showing forming load with respect to stroke. 5a and 5b are the lower die, 6a and f3b are the punch, ? . 8 is the escape part.

Claims (1)

[Claims] Punches 6a and 6b whose outer parts fit tightly into the lower molds 5a and 5b
The molding process is carried out in multiple steps, and in the first molding process, the molded product is molded using a mold that releases the parts that are likely to have insufficient thickness, and in the next molding process, the parts formed in the previous molding process are molded. A closed incremental forging method characterized by molding using a mold with a portion corresponding to .