RU2501626C2 - Method and device for blade forging - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to metal forming and can be used in production of turbine blades. Initial blank is placed in horizontal intake of split female die composed of two split followers. Split followers have horizontal opening to make said intake and radial cavities for blades. Axial force is applied to blank both ends by male dies arranged on both sides. Blank is strained unless a complete filling of blade cavities to produce multiple-piece forged piece. Forged piece consist of blades connected by butt-end. Forged piece is withdrawn from the mould to detach the blades from butt-end.

EFFECT: higher ductility, lower moulding force, higher precision and metal recovery.

4 cl, 18 dwg, 1 ex

Description

The invention relates to the processing of metals by pressure, and can be used to obtain turbine blades by hot stamping, and more specifically for blades that are used in aircraft gas turbine engines (GTE).

As you know, GTE blades are the most massive parts in the production of engines, so their production is highly labor intensive and, accordingly, significant costs. This especially applies to the shoulder blades that I get! pressure treatment method - hot stamping. Currently, the traditional technological scheme is most widely used: pre-harvesting is obtained by disembarkation on the gas-condensate field, and then it is stamped in open dies on a press or a hammer in several operations, with cutting of the flake after each stamping.

In this regard, punching methods were developed when several pieces of blades were obtained from one billet, the so-called "multi-piece punching". For example, a method for multi-piece stamping of blades is known (Author's certificate. No. 994101, B21K 3/04, 02/07/83). According to this method, in ordinary open dies, forgings for several pieces of blades were obtained. Then, in the cut stamp, the blades are separated from the burr, and then processed separately. Practice has shown that the lot method has many disadvantages. For example, the area of flashing in the forging increases significantly, and this leads to additional consumption of material and a low coefficient of its use (CMM). In addition, with open stamping, it is not possible to obtain high degrees of deformation, especially in the area of the pen blade. And this significantly affects the quality of the material structure of the blade, which determines the service properties of these parts, which leads to low durability in operation.

A known method and device for the manufacture of blanks such as discs with blades (US patent No. 4530229, B22D 22/00, Jul. 23, 1985, "Forging method and die package therefor"), in which the original blank is placed in a sectional split matrix, apply a punch the deformation force to the upper end of the workpiece, and the original workpiece is deformed filling the cavities between the stamp sections until the current is completely shaped.

A known method of stamping blades, which is implemented in a stamp (SU 1682028 A1, B21K 3/00, 10/07/1991), including placing the workpiece in a multi-channel matrix, applying axial force to it and deforming it to fill cavities (channels) in the matrix, to obtain multi-piece forgings, consisting of blades connected by a pressure switch, which I remove! from the stamp and the blades are separated from the pressure switch.

The disadvantages of this method are: large specific efforts to deform the workpiece, as a rule, exceeding the tensile strength of die tooling, which is associated with unilateral application of force, as well as the complexity and high cost of the stamp. With a unilateral application of force, there is a restriction of the plastic flow of the metal, as a result of which the friction forces of the metal on the walls of the stamp increase, which leads to an increase in the stamping force.

The objective of the present invention is to ensure the effectiveness of multi-piece stamping of the blades, increasing ductility at the expiration of the metal of the workpiece in the side cavity of the stamp, reducing technological effort, improving the accuracy of stamped products, increasing CMM.

The solution to the problem is achieved by placing the initial billet in a horizontal matrix receiver, consisting of two half-matrices with a vertical plane of the connector, and using the punches located on both sides of the billet, applying axial force to both billets of the billet, deform the billet until the cavities under the blades are completely filled, but in the shape and size of the respective blades, so that a multi-piece forging is obtained, consisting of blades connected by a pressostat, which is then removed and the blades are separated from pressure switch.

A device for implementing the method, comprising a punch tool consisting of a fixed and a moving part, is characterized in that the detachable matrix consists of two half-matrices with a vertical plane of the connector, in which a horizontal through hole is formed that forms the receiver and the cavities are radially arranged relative to the receiver in shape and the dimensions correspond to the blades, each half matrix having its own punch.

According to the invention, cavities for shaping the blades (pen and lock) can be made in the plane of the half-matrix connector or perpendicular to the plane of the half-matrix connector.

The invention is illustrated by drawings.

Figure 1 shows a device for implementing the proposed method. Figure 2 shows a view aa of the device of figure 1.

Figure 3 shows another device for implementing the proposed method.

Figure 4 shows a view aa of the device of figure 3.

5 and 6 show the stamping steps of the proposed method.

In Fig.7 shows obtained by the proposed method multi-piece forging.

On Fig shows a section along aa of the forgings of Fig.7.

Figure 9 shows the workpiece of the blade, separated from the pressure switch.

Figure 10 shows another forging obtained by the proposed method.

Figure 11 shows a section along aa of the forgings of figure 10.

On Fig shows a specialized press model PMG-2.

13-16 show the stamping steps on the PMG-2 press.

On Fig shows a photograph of the obtained multi-piece forgings.

On Fig shows a photograph of the obtained blanks of the blades.

The method is as follows.

A device for implementing the method of stamping blades is a stamp set of figures 1 and 2. The kit includes a detachable matrix 1, consisting of two half-matrices 2 with a vertical plane of the connector, in which a horizontal through hole is formed, forming the receiver 3, and cavities radially located relative to the receiver 4 in shape and size corresponding to the blades, and each of the half-matrix 2 is equipped with its own punch 5.

According to the invention, the cavities 4 for shaping the blades (pen 6 and lock 7) can be made in the plane of the connector of the half-matrix 2 (see FIGS. 1 and 2) or perpendicularly to the plane of the connector of the half-matrix 2, as shown in FIGS. 3 and 4.

The half-matrix 2 is closed along the plane of the connector, so that they form a closed matrix 1, as shown in Fig.5. The initial cylindrical workpiece 8 is inserted into the receivers 3. Then, with the punches 5, which enter the receivers 3 on both sides, the workpiece 8 is deformed in the cavity of the closed die 1. As a result of the bilateral application of force to the workpiece 8, the metal of the initial workpiece 8 is extruded into the side cavities 4 which in shape and size correspond to the blades. The position of the punches 5 at the end of the stroke after the complete formation of the blades is shown in Fig.6. After stamping, the finished forgings 9 are removed, opening the half-matrixes 2. The forgings 9, as shown in Figs. 7 and 8, are several (in this case four) blanks of the blades 10 connected by locking parts 7 to the pressure switch 11. Then, the resulting lot the forging 9 is placed in a cutting stamp and the blades 10 are separated from the pressostat 11. The stamped blade blank obtained in this method, which is shown in Fig. 9, has minimal allowances for further machining, since it was deformed th in a closed stamp. In addition, the plastic deformation of the initial workpiece 8 occurs with bilateral application of force from the punches 5, and this provides favorable conditions for the formation of the blades and high degrees of deformation due to lateral extrusion. Figure 10 and 11 shows the forging obtained in the matrix 1, where the cavity 4 is made perpendicular to the plane of the connector of the half-matrix 2 (see figure 3 and 4). In such a stamp, you can get a larger number of blades in one forging (see figure 10), but the design of the matrix is more complicated and its cost will be higher.

Deformation using double-sided pressing is preferable to one-sided one, since the plastic deformation center is located symmetrically, there is no restriction of the plastic flow of metal, characteristic of one-sided deformation, as a result of which the friction forces of the metal along the stamp walls are reduced, which leads to a reduction in the stamping force. In addition, double-sided stamping doubles the deformation rate. This provides a very high ductility of the metal during stamping, which guarantees the production of complex forgings by extrusion into the side cavities of the stamp, and extremely high degrees of deformation are achieved under conditions of comprehensive non-uniform compression. As a result, the metal structure is worked out and compacted and, accordingly, the mechanical strength indicators of the obtained blade blanks are increased.

An example implementation of this method.

Using this method, gas turbine compressor blades were made with a length of 43 mm, a feather width of 22 mm, and a lock of 27.5 mm from VT8 titanium alloy. The dimensions of the initial blank: diameter 30 mm, length 141 mm. The billet is heated in a special installation, which is a mechanized furnace bath. Heating in it occurs in a molten salt of the composition: 95% BaCl2 + 5% MgF2, at a temperature of 960 ± 10 ° C. This protects the surface of the workpiece during heating. In addition, the layer of barium salts on the surface of the workpiece is an excellent lubricant for its deformation.

The device is installed on a press model PMG-2, working on the principle of double-sided stamping. This press (Fig. 12) has a horizontal bed on which sliders 12 are mounted bearing half-matrixes 13 and sliders 14 are bearing punches 15. Each group of sliders has an independent drive. Two sliders 14 carrying punches 15 are located symmetrically on adjustable guides and are driven by screw mechanisms. The sliders 12, to which the half-matrices 13 are attached, are mounted on the bed in the same guides and have a longitudinal displacement drive from the hydraulic cylinders. To create the clamping force of the tool (half-matrix), a special mechanism is provided in the slide of the press. To obtain stable part sizes and tool life, it is necessary to adjust the impact energy, which is performed on this press by changing the pressure of the gas-hydraulic accumulator. In addition, this press has a safety device that can limit the technological effort.

Press Specifications

Rated force, t.s. 250 Kinetic energy, tcm 5 Drive power kW 60

Overall dimensions, mm:

Length 7800 Width 4650 Height 2500 Weight kg 20000

The sliders 12 are moved together in the middle part of the bed, so that the half-matrix 13 are closed, forming a closed matrix, as shown in Fig.13. The heated preform 16 is inserted sideways into the matrix receiver (see FIG. 14). Then include the working stroke of the sliders 14. At the end of the working stroke, the punches 15, mounted on the sliders 14, enter the receivers of the half-matrix 13, and the workpiece 16 is deformed in the cavity of the closed matrix. In this case, the kinetic energy of the moving parts of the screw press accumulated during the acceleration course is converted into plastic work of the workpiece. As a result of the two-sided application of force to the workpiece 16, metal is extruded into the side cavities 4 of the stamp (see Fig. 1 and Fig. 3), which correspond in shape and size to the blades. The position of the sliders 14 at the end of the stroke is shown in FIG. After stamping, the finished forging 18 remains in one of the half-matrix 13 and must be removed from it. To this end, the sliders 12 are moved along the guides, making the half-matrices 13 open. At the same time, the forging 18 is ejected due to its interaction with one of the punches 15. Then the sliders 12 continue the course of the connector until they meet with the sliders 14, after which the sliders 14 move simultaneously. until it stops in the frame, as shown in Fig.16.

From one cylindrical billet, a four-piece forgings were obtained for blanks of gas turbine compressor blades, as shown in the photograph of FIG. Forgings are obtained in the described manner in a stamp set similar to that shown in FIG. In this case, the shape and dimensions of the obtained blade blanks are close to the finished part, since they are formed in the cavities of the closed matrix. The resulting blanks of the blades were separated from the remaining part of the blank, the so-called pressostat, in a cut stamp. Then, the stamped blade blanks shown in FIG. 18 underwent machining operations to remove the allowance and surface finish according to traditional technology. At the same time, the number of machining operations has sharply decreased, since the machining allowances are very low. The control and testing of the blades obtained by this method showed that they satisfy all the requirements of the technical conditions, both in the structure of the material and in the mechanical properties.

As a result of applying this method and device for stamping blades, the following indicators are achieved:

- The utilization of the material (CMM) is not less than 0.35.

- High productivity, since 4 pieces of blades were obtained in one press stroke.

- Improving the structure and mechanical properties of the material of the scapula.

- Reduced labor costs by 30% by reducing the number of machining operations.

Claims (4)

1. The method of stamping the blades, including placing the original billet in the detachable matrix of the die set, applying axial force to the workpiece and deforming until the cavities under the blades are filled, followed by separating the blades from the press residue, characterized in that the initial billet is placed in a horizontal receiver of the detachable matrix, consisting of two half-matrices with a vertical plane of the connector, and by applying axial force to both ends of the workpiece by means of horizontal punches nick produce deformation of said preform to a complete filling of the cavities under the blades radially arranged in the horizontal split matrix receiver. 2. A device for stamping blades, containing a stamping kit with a split matrix, characterized in that the split matrix consists of two half-matrices with a vertical plane of the connector, which are made with a horizontal through hole forming a horizontal receiver and radially spaced relative to the receiver cavity under the blades, the shape and size of the respective blades, each half-matrix is equipped with its own punch, while the punches are installed with the possibility of entering into a horizontal receiver at both sides. 3. The device according to claim 2, characterized in that the cavity under the blades are made in the plane of the connector of the half-matrix. 4. The device according to claim 2, characterized in that the cavity under the blades are made perpendicular to the plane of the connector of the half-matrix.

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