RU2374027C1 - Manufacturing method of forgings of variable cross-section by hot extrusion with movable dies - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: invention relates to metal deformation process and can be used at extruding of details of variable cross-section on hydraulic presses. Extruding is leaded into compose matrix containing travelling semi-matrix with usage of feather system. Feathers are interlocked to press ram and are outfitted by separate system of hydraulic drive. Variable cross-section of forging is formed by means of broadening of compose matrix ensured by separation of movable semi-matrixes under action of deformed metal at movement of wedge upwards.

EFFECT: saving metal and reduction of extrusion efforts.

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Description

The invention relates to the processing of metals by pressure and can be used in stamping by extrusion of parts of variable cross-section on hydraulic presses with movable semi-matrices.

A known stamp for extruding blades, containing a cage with a conical socket, a detachable matrix placed in it with inserts on half-matrices, forming an engraving of the castle and feather parts of the blade (SU 1518997 A1).

The disadvantage of this method is the inability to obtain stampings of variable cross section (especially in the manufacture of blades), high deformation force, increased wear of working tools, as well as the possibility of not filling engravings.

A known method of manufacturing hot stamping forgings on presses with a movable container, comprising supplying a heated billet to the container, pressing a press washer in the container and pressing a part of the workpiece into a matrix included in the matrix unit, with the remaining part of the workpiece being upset in the plane between the mating planes of the matrix unit and a container (RU 2259897 C1, B21C 23/03, B21J 5/06).

The disadvantage of this method is the impossibility of manufacturing high-precision parts of variable cross section, as well as the complexity of controlling the synchronous movement of the press washer and container.

Closest to the claimed is a stamp for extrusion, mainly of blades, containing conical detachable matrixes mounted in a housing with a conical cavity and with wedges for divorcing the matrices and an ejector. In this case, the half-matrix is made with protrusions and depressions located symmetrically relative to the plane of the connector (SU No. 441087 A1, 08/30/1974, B21K 3/04, B21J 13/02).

The disadvantage of this method is the ability to jam semi-matrices during their disclosure, as well as the inability to obtain blanks of variable cross-section not only of the blades, but also of other parts with a variable profile.

The technical result achieved by the implementation of the invention is the ability to obtain blanks of variable cross section, approaching the finished product by extrusion, which leads to economy of metal and lower extrusion force by reducing the friction surface between the workpiece and the tool. The friction surface is reduced by reducing the height of the belt of the matrix (Figure 1).

The technical result is achieved by the fact that in the proposed method of manufacturing stampings of variable cross section by hot extrusion with movable semi-matrices, a system of wedges kinematically connected with a press slider and having a separate hydraulic drive system, stamping is obtained due to the given wedges moving upwards and sliding the half-matrices during metal deformation.

In the manufacture by this method, the extrusion force is reduced by reducing the friction surface, and, as a result of this, the wear of the working surfaces of the tools is reduced.

The movement of the wedges up is set based on the angle α, characterizing the conicity of the blades, which, in turn, is associated with the flow rate of the metal V _East. (Figure 3).

The presented technological scheme (Fig. 1) contains an upper plate with a punch fixed to it, a lower plate on which two half-matrixes are placed. Two wedges with a separate hydraulic drive system and an ejector are located in the plate openings. On semi-matrices is a container for the workpiece.

The stamp works as follows.

When lowering the press slider with the plate 1 and the punch 2 fixed on it, the connection between the wedges 3 and the slider starts to work. At a certain value of the slide movement (which is determined based on the specific dimensions of the workpiece and the technological characteristics of the press, such as the speed of the slide, and the technological characteristics of the process, such as temperature, degree of deformation, drawing ratio), the wedges 3 begin to move up the container 4. As a result a gap appears between the half-matrices 5, 6 and the wedges 4. Under the action of the deformable metal 7, the half-matrices 5, 6 are moved apart by the size of this gap (Figure 2).

The heated billet is fed into the container, the billet is extruded through the channel of the composite matrix (Figure 1), consisting of left and right conical half-matrices. When this form stamping of variable cross section, expanding to the remaining part of the workpiece in the container (Figure 2). The specified stamping variable cross section is formed by expanding the composite matrix through a system of wedges (Figs. 1, 2). As a result, it is possible to obtain complex stampings in one technological transition, the range of technological tools is reduced and the quality of the resulting product is improved.

An example of determining the angle of inclination of cones

Consider extruding a blade blank for stamping. Consider a blade having the following dimensions in sections (Figure 4). The sections of the blade in the near-end and final sections with allowance for machining are presented.

From geometric considerations, the angle of cone of the blade α is equal to:

where h ₀ and h _k are the width of the scapula in the adjacent and final sections of the scapula, respectively;

l is the length of the feather blades.

The amount of movement of the wedges to the i-th section is determined by the formula:

where τ is the extrusion process time;

V _source = const - the rate of metal flow through the matrix point, depending on the conditions of the extrusion process [Theory of metal pressing, 2nd ed. Perlin I.L., Reitbarg L.Kh. M., Metallurgy, 448 p., P. 61]:

where λ is the drawing coefficient;

F _k is the cross-sectional area of the container;

F _n is the cross-sectional area of the matrix channel;

V _press - pressing speed.

Then the gap, which must be between the matrix and the wedges to obtain the i-th stamping section, is:

where h _i is the width of the blade in the i-th section.

Then the angle of inclination of the wedges is equal to:

where l _i - the length of the feather blades in the i-th section.

Further determination of the size of the tool depends on the equipment on which the extrusion process takes place, on the overall dimensions of the blade.

During this process, stamping of variable cross-section is obtained and it becomes possible to obtain precise stampings, for example blades, close in size to the finished part.

Claims (1)

A method of manufacturing stampings of variable cross-section by hot extrusion on presses into a composite matrix containing movable semi-matrices using a system of wedges kinematically connected to the press slider and equipped with a separate hydraulic drive system, characterized in that the extrusion is carried out by expanding the composite matrix by sliding the movable semi-matrices under the action deformable metal when moving wedges up.

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