RU2381083C1 - Manufacturing method of scapular blanks - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to manufacturing on hydraulic pipe-profiled press of blanks for manufacturing of turbine blades, and also other types of rotor-type blades or blades of stator for turbomachines or propellers, mainly from titanium alloys. Method includes pressing of ring blank, which is installed on mandrel in container. It is implemented its straight and backward extrusion in to two symmetric cavities. One cavity is located between containers and die block, which is between compression ram and container. Received blank is subject to sequentially thermal and mechanical operation. Then it is cut for sectors, and sectors are subject to dressing up to receiving of plates. Plates are cut for symmetric scapular blanks.

EFFECT: receiving on universal press, stove and machining facilities of scapular blank with rational geometry, structure and texture of metal.

2 cl, 1 ex, 4 dwg, 1 tbl

Description

The invention relates to the processing of metals by pressure, and in particular to the manufacture of blanks on hydraulic tube presses for the production of turbine blades, as well as other types of rotor blades or stator blades for turbomachines or propellers, mainly from titanium alloys.

The manufacturing process of the blades should ensure their high quality, reliability and a given resource. However, when choosing a method for processing large-scale batches of parts, such as blades of gas turbine engines, it is necessary to take into account economic efficiency.

Most turbine blades used in aircraft engines and other similar systems are hollow, which circulates the cooling medium inside them. Currently, one of the most advanced technologies for manufacturing a hollow blade is the method of superplastic forming of titanium alloy billets, combined with diffusion welding. In this case, stamped blanks of variable section and sheets with a fine-grained structure are used as initial components.

The use of machining of workpieces having ending parts leads to the fact that a large volume of expensive material, amounting to more than 40%, is converted into shavings and trimmings. Therefore, this method for economic reasons is unattractive.

A known method for the production of blades (US Patent No. 6,739,049). The manufacturing process for the manufacture of blade blanks involves cutting titanium plates into rectangular wedge-shaped products of suitable length and thickness. Each part is cut in the longitudinal direction along an inclined plane to obtain two separate identical conical panels, which will later become the side components of the blade. Cutting is done with a band saw. The advantage of this method is that it is more economical in terms of using the material. The disadvantages of this method include the fact that the process involves the availability of special equipment, is performed using an expensive tool and is inefficient. In addition, the stringent requirements for the formation of the texture (given the orientation of the grains of the alloy) of the blade during the manufacture of blanks make this method difficult to implement.

A known method of manufacturing hot extrusion stampings on presses with a movable container, comprising feeding the heated preform to the container, extruding the preform in the container with a press washer, compressing part of the preform into a matrix included in the matrix assembly, forming a stamping with part of a constant section and forming on said stamping thickening by precipitation of the remaining part of the workpiece, part of the matrix node is placed in the container from the conditions for ensuring the conjugation of their planes, and the rest of the remaining part preparations during the formation of a thickening are carried out in the cavity between the mating planes of the matrix assembly and the container, which is formed by moving the matrix assembly relative to the container before the thickening is formed, and the sediment is produced by synchronously moving the press washer and container (RF Patent No. 2259897, published 2005.09.10, IPC V21C 23/03).

This method allows for a single installation of the workpiece to produce the design of complex internal and external stamping surfaces. The sequential design of the internal and external contours of the part reduces the stamping force, increases the tool life and improves the quality of the part. The invention provides a non-waste process, minimizing the specific forces on the tool and increasing its durability, high quality products, expanding the technological capabilities of hot die forging to increase the complexity of the shape of the outer contour and cavity and improve the service properties of parts using metals and alloys of increased strength. The technological capabilities of universal hydraulic presses with a moving container are also greatly expanded.

The disadvantage of this method is that it allows you to form thickenings only on the outer side surface, in addition, the cavities of the stamping elements are created due to the coordinated movement of the matrix unit, container and press stamp relative to each other, which, due to the large inertia of the moving parts of the press and considerable efforts perceived by them move with a relatively large error. These factors limit the accuracy of the geometrical dimensions of the pressed billet. In addition, the stamping process is extended over time, as a result of which the elements of the workpiece are formed at different temperatures, leading to a spread in their mechanical and structural properties.

A known method of manufacturing blanks of blades, for example, a compressor of a gas turbine engine. By extrusion, a preform is obtained in the form of an I-profile with a jumper thickness of not less than a predetermined maximum pen thickness of the blade preform. The thickness of the shelves of the profile is not less than the specified maximum thickness of the shank of the blade blank. The resulting I-beam profile is divided into fragments with a length not less than the specified width of the shank of the blade blank. After extruding the I-beam, it can be rolled or drawn. The resulting workpiece of the blade is twisted along its longitudinal axis (RF Patent No. 2254200, publ. 06/20/2005, IPC V21K 3/04) - prototype.

The disadvantage of this method is a significant complication of the process, due to the appearance of labor-intensive additional technological operations, high labor costs and energy costs.

The problem to which this invention is directed is an economical and high-performance method for producing blade blanks with constant mechanical and structural properties.

The technical result achieved by the implementation of the invention is the creation of a stable process for producing, on universal press, furnace and machine tool equipment, a blade blank having a rational geometric shape, a predetermined regulated structure and metal texture.

The specified technical result is achieved by the fact that in the method of manufacturing blade blanks, comprising pressing an annular blank mounted on a mandrel in a container that is closed with the matrix unit, by extruding it by the stroke of the stamp into two symmetrical cavities, one of which is located between the container and the matrix node, and the second between the stamp and the container, while direct extrusion of the annular workpiece into the cavity between the container and the matrix node and reverse extrusion into the cavity between the ram and the container, the resulting preform was sequentially subjected to thermal and mechanical treatment, cut into a sector, and the sector is subjected to editing to obtain plates which are cut into symmetrical blade preform.

Sectors are subjected to creep annealing editing at a load value that provides a creep rate of 10 ⁻⁵ −10 ⁻⁸ s ⁻¹ at annealing temperature.

The invention is illustrated by drawings, where in Fig.1 shows the blade blank 1 with the ending part 2, in Fig.2 - at the top, the initial position before the pressing operation of the matrix unit 3, container 4, mandrel 5, ring blank 6, press washers 7 and press stamps assembly 8, at the bottom - extrusion of the intermediate blank 9 in the cavity 10 and 11, figure 3 - sector 12, obtained after cutting the intermediate blank 9, figure 4 - scheme of cutting straightened sectors on the blade blanks 1.

The method is as follows: the annular blank 6 is heated and mounted on the mandrel 5 in the container 4, the matrix assembly 3 and the container 4 are closed, then a press washer 7 is pressed into the cavity 10 by direct extrusion between the container and the matrix assembly and backward extrusion into the cavity 11 between the press stamp assembly 8 and the container, after pressing in the intermediate blank 9 is removed from the container, heat treatment is performed to relieve residual stresses, then turning into specified sizes. After turning to the specified dimensions, the intermediate workpiece is cut into sectors. Sectors have small thicknesses, so either isothermal dressing or crypt annealing is used to edit them. The resulting plates are cut into symmetrical blade blanks, which are used in pairs in the manufacture of hollow blades, because they have identical strength and structural characteristics, as well as the texture of the feathers, which was formed by the flow of metal when pressing the Central protrusion to the periphery or direct or reverse extrusion.

Concrete example

To test the manufacturing technology of blade blanks, an annular blank of Ti-6Al-4V alloy with dimensions of ⌀246 × ⌀150 × 155 mm was pressed, which was heated to a temperature ТП 50 ... 100 ° С in an electric resistance furnace. The heated billet was placed in a 3150 tf press container with a working sleeve diameter of ⌀ 250 mm. The container and the matrix unit were closed by setting the container to “clamp”, and the metal was pressed out by direct extrusion into the cavity between the container and the matrix unit and backward extrusion into the cavity between the stamp and the container.

After removing the pressed billet with dimensions ⌀247 × 21221 × 135 mm at the ends and an internal protrusion with dimensions of ⌀247 × ⌀149 × 65 mm, the workpiece was heat-treated for solid solution according to the TPP mode of 30 ° С for 2 hours, mechanical processing was performed for dimensions ⌀ 242 × ⌀226 × 135 mm at the ends and on the part with an internal protrusion of ⌀242 × ⌀156 × 51 mm. Then, the machined workpieces were cut along a generatrix parallel to the axis into 6 sectors with a width of 122-124 mm, which were straightened in dies heated to the metal heating temperature, followed by cutting the sectors along the symmetry axis into 2 workpieces. The dimensions of the resulting blade blanks are 8 × 126 × 160 mm.

The mechanical properties of the blade blank are shown in the table.

The mechanical properties of the blade blank Cutting direction σ _0.2 , MPa σ _in , MPa δ,% ψ,% In the direction of pressing 876 965 17.6 40.6 Across the direction of pressing 929 1008 15.0 39.5

The microstructure of the blade blanks corresponds to deformation and heat treatment in the (α + β) region. The degree of globularization is 90%, the amount of α-phase is 80%. The grain size is 4-8 microns in the longitudinal direction, 2-4 microns in the transverse direction.

The advantages of this method is that it:

- allows you to make a blade blank as close as possible to the finished part, does not require additional machining;

- forms a homogeneous microstructure oriented along the axis of the blade, which ensures an increase in resource during operation of the blade;

- forms the optimal metal flow lines in the transition zone from the castle to the pen:

- more economical in terms of metal use;

- the cylindrical shape of the molded product provides manufacturability during machining;

- expands the possibility of tube-profile presses.

Claims (2)

1. A method of manufacturing a blade blanks, characterized in that it involves pressing an annular heated billet mounted on a mandrel in a container that is closed with the matrix unit by extruding it by the stroke of the stamp into two symmetrical cavities, one of which is located between the container and the matrix unit and the second between the stamp and the container, while direct extrusion of the annular workpiece into the cavity between the container and the matrix node and the reverse extrusion into the cavity between the stamp and container, the resulting workpiece is subsequently subjected to heat and machining, cut into sectors, and the sectors are straightened to obtain plates that are cut into symmetrical blade blanks. 2. The method according to claim 1, characterized in that the sectors are subjected to creep annealing editing at a load value providing a creep rate of 10 ⁻⁵ −10 ⁻⁸ s ⁻¹ at annealing temperature.

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