JPH06102244B2 - Turbin blade forging method - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for stamping and forging long blades for steam turbines, and particularly forging long blades suitable for stamping and forging titanium alloy having poor hot workability. It is about the method.

[Prior art]

The conventional stamping and forging method is a method of stamping using one upper die and one lower die attached to a forging machine, and each die has a female shape engraved according to the shape of the moving blade. The forged round material 3 shown in the figure is supplied and stamped and molded using a press (FIG. 6) or by striking to manufacture a turbine blade material 3a shown in FIG.

1 shown in FIG. 6 is an upper die (more specifically, an upper die), and 2 is a lower die.

FIG. 7 (A) is a plan view, FIG. 7 (B) is a side view, and FIG. 7 (C) is an end view.

Regarding this type of die forging, for example, Japanese Patent Publication No. 59-11375
The techniques described in JP-A No. 60-184445 and JP-A No. 60-184445 are known.

FIG. 8 shows an example of a turbine blade press die according to the prior art, and (D) is a plan view. (E), (H), and (K) show cross-sectional views of the E-E plane, the H-H plane, and the K-K plane, respectively. J
Indicates the forging surface and arrow F indicates the forging direction.

When the upper mold 1 is removed in the state of FIG. 8 (D) and the rod-shaped material 3 (FIG. 5) is placed on the lower mold 2, it is as shown in FIG. 9 (L). When the upper mold 1 is placed on the lower mold in this state (L) and the EE cross section, the HH cross section, and the KK cross section are drawn, the respective figures 9 (E), (H), It becomes like (K).

In this state (Fig. 9), the upper die 1 is rolled down and the material 3 is plastically deformed to obtain the product of Fig. 7, but the hot workability is poor, for example, titanium alloy or 12Cr stainless steel. Forging with a material requires a large capacity press or hammer.

[Problems to be solved by the invention]

FIG. 10 shows the relationship between the forged part surface of titanium alloy die forging and the required forging force obtained by the simulation test. For example, in the case of a 40-inch titanium alloy with a forged area of about 2400 mm ² , the hammer capacity conversion required forging force is about 63 t.
-M and domestic existing equipment is 35-40 m-t,
The conventional forging method requires about twice as much force. Fig. 11 shows the results of the model test for the relationship between the forging direction, the inclination of the manufacturing surface, and the forging force. It shows that the forging force extremely decreases when the inclination angle exceeds 50 °.

As can be understood from these figures, forging using a titanium alloy material requires a very large pressing force. That is, a large-scale press facility is required, and the facility cost becomes enormous.

Further, since it is difficult to mold in one forging step, if heating and molding are repeated, crystal grains grow and become coarse, and the mechanical properties deteriorate.

Further, as is clear from the above-mentioned chart, if the normal line of the forged surface is inclined with respect to the pressing direction (forging direction), the working capacity will be significantly reduced.

Since the turbine blade is a member having a three-dimensional twist angle, it is difficult to avoid occurrence of a difficult forging portion and an easy forging portion in the relationship between the forged surface and the forging direction. For this reason, forging having a twist angle of 90 ° from the root to the tip of the blade was very difficult to forge by the conventional technique.

The present invention has been made in view of the above circumstances, for example, using a material having poor hot workability such as titanium alloy or 12Cr steel, it is unlikely to cause crystal grain coarsening due to reheating, and has a small capacity. It is intended to provide a method for forging a turbine blade with soundness and high accuracy by using the forging equipment of.

[Means for solving problems]

In order to achieve the above object, the present invention is a method of forging a turbine blade by deforming a rod-shaped material heated using an upper die and a lower die into a flat shape, in which the finish shape of the turbine blade is changed in the longitudinal direction. Therefore, the upper and lower molds are divided into a plurality of areas, and the upper and lower molds are divided into a plurality of parts each having a lap portion with an adjacent area and corresponding to the plurality of areas, and the divided upper and lower molds are used. The above-mentioned material is forged in each area.

Further, according to the present invention, at least one set of the upper and lower dies divided into a plurality of parts corresponding to the plurality of areas faces a work part other than the area to be forged through a clearance. It is characterized in that the members are integrally connected to each other, and the support member holds the processed portion other than the forged area.

[Action]

According to the above method, the turbine blade is divided into a plurality of areas, and forging is performed on each of the areas, so that even a small-scale forging facility can be easily forged using a material having poor hot workability. I can. In other words, by adopting a split die, the forging area for each operation can be determined according to the installed capacity, and die casting forging can be performed even for turbine long blades made of materials with poor hot workability such as titanium alloys. Can be done.

In particular, in the present invention, since the upper die is divided into a plurality of areas and the lower die is overlapped with the adjacent area, it is possible to prevent the displacement of the boundary portion caused by the split forging, and At least one of the upper and lower molds
In the set, since the support member, which is opposed to the portion to be processed other than the area to be forged via the clearance, is connected, the portion to be processed can be held by the support member to prevent bending.

〔Example〕

Next, one embodiment of the method of the present invention will be described with reference to FIGS. 1 to 4.

In this embodiment, a rod-shaped (specifically, stepped round bar-shaped) material 3 as shown in FIG. 5 is used to mold a turbine blade as shown in FIG. As shown, the forging range G1 of the root side half is forged, and then the forging range G2 of the tip side half is forged as shown in FIG. Illustrated
G3 is the lap part.

The first forging in the G1 range shown in Fig. 2 is the finished product (7th
The upper mold and the lower mold corresponding to the half of the surface area in the figure). FIG. 3 shows a die configured to forge the above G1 range.

FIG. 3 (Q) is a plan view of the lower shape 2a. Upper mold on this
When 1a is placed and cut along the RR plane and the SS plane, the results are as shown in FIGS. 3 (R) and 3 (S). J indicates a forged surface.

The unforged part G2 shown in FIG. 2 is heated and the parts are forged by the dies 1b and 2b shown in FIG. 4 to obtain the product of FIG.

FIG. 4 (T) is a plan view of the lower mold 2b. FIG. 4 (U), (T), (S) shows the upper mold 1b placed on the lower mold 2b and cut along the U-U surface, T-T, SS surface.

In carrying out the present invention, the upper and lower molds are shown in FIG.
It is also possible to configure only the G2 part shown in.

Also, it can be divided into three sections as shown in G3, G4, G5. Although illustration is omitted, it may be divided into four, or more significantly. The larger the number of sections, the easier it is to forge large turbine blades with small equipment. In either case, the surface area of the finished product should be divided into approximately equal parts and a wrap portion should be provided.

The molds (upper mold 1b and lower mold 2b) of this embodiment are constructed by using the G2 area shown in FIG. 4 (T) as a forging mold and constructing the G1 'portion in the drawing as follows.

That is, a female type (see FIG. 4 (T)) that faces the already-formed portion G1 as shown in FIG. 1 through a minute clearance.
G1 'part) is constructed integrally. When the forging process is performed in this way, the forged part is forged in the forging range G2 shown in Fig. 2.
Since G1 is held by the above-mentioned female portion, bending can be prevented.

In addition, the provision of the forged lap portion G3 shown in FIG. 1 has the effect of preventing the deviation of the boundary portion expected to occur due to the split forging.

In addition, when applying the method of the present invention to divide into turbine blades and a plurality of areas and divide and forge each area,
If it is difficult to forge and mold a certain area only once, the area can be forged in multiple times by using a plurality of types of upper and lower molds. This makes it easy to gradually bring the forged surface closer to the forging direction.

〔The invention's effect〕

As described above, according to the forging method of the present invention, for example, using a material having poor hot workability such as titanium alloy or 12Cr steel, it is unlikely that coarsening of crystal grains occurs due to reheating,
It has the excellent practical effect of being able to forge turbine blades with soundness and high precision using a small capacity forging equipment.

[Brief description of drawings]

1 and 2 are perspective views for explaining a processing step of a turbine blade in an embodiment of the present invention. FIG. 3 is an explanatory view of the first forging die in the above embodiment, and FIG. 4 is an explanatory view of the same second forging die. FIG. 5 is a perspective view of a turbine blade forging material, and FIG. 6 is a schematic front view of a forging machine. FIG. 7 is a three-view drawing of a turbine blade forged product. FIG. 8 is an explanatory view of a turbine blade forging die in the prior art, and FIG. 9 is an explanatory view of a forging state similarly. 10th
FIG. 11 and FIG. 11 are charts for explaining the technical problems in the construction. DESCRIPTION OF SYMBOLS 1 ... Upper mold for turbine blade forging of a conventional example, 2 ... Similarly lower mold, 1a, 1b ... Upper mold for turbine blade forging in one embodiment of the present invention, 2a, 2b. 3 ... Material for forging.

Claims (6)

[Claims] 1. A method for forging a turbine blade by deforming a heated rod-shaped material into a flat shape by using an upper die and a lower die, wherein the finish shape of the turbine blade is divided into a plurality of areas along its longitudinal direction. The upper and lower molds are divided into a plurality of parts, each of which has a wrap portion with an adjacent region, and the above-mentioned divided upper and lower molds are used to divide the material into the respective regions. A method of forging turbine blades, characterized by forging each of them. 2. For at least one of the plurality of areas, forging is performed a plurality of times using a plurality of types of upper and lower dies for the area, and the direction of the surface to be forged is changed for each time. Characterized by making the forging direction approach,
A method for forging a turbine blade according to claim 1. 3. A support that at least one set of upper and lower dies divided corresponding to each of the plurality of areas faces a processed portion other than the area to be forged via a clearance. The turbine blade forging method according to claim 1, wherein the members are integrally formed in a continuous manner, and the support member holds the processed portion other than the forged area. 4. For at least one of the plurality of sections in the above item c, forging is performed a plurality of times using a plurality of types of upper and lower dies for each section, and the direction of the surface to be forged is determined for each time. The turbine blade forging method according to claim 1, wherein the forged surface is changed closer to the forging method. 5. The upper and lower molds, which are divided by corresponding to each of the plurality of sections of the item b, are constructed by wrapping the adjacent sections in the adjacent section. The described turbine blade forging method. 6. At least one of the upper and lower molds divided into a plurality of sections corresponding to each of the plurality of sections of the item b is provided with a clearance to a work portion other than the section to be forged. The turbine blade forging method according to claim 1, wherein the supporting members facing each other are integrally connected.