RU2347645C1 - Method of ultrasonic forming of long-length items out of powder materials - Google Patents

Abstract

FIELD: metallurgy.

SUBSTANCE: simultaneously there are performed forming of hollow casing from band, filling casing with powder material and inserting wire into its cavity. Oscillations of ultrasonic frequency are transmitted to wire; by means of screwing the wire is shaped into a spring. Projections with height exceeding diameter of wire are formed on coils of the spring or on wire.

EFFECT: facilitating control of impregnation degree and uniformity of item impregnation at increased diameter.

9 cl, 11 dwg

Description

The invention relates to the field of powder metallurgy and can be used in various sectors of the economy, for example in mechanical engineering.

A known method of forming long products from powder materials, including, sequentially carried out the manufacture of a shell of an electrically conductive material, loading the powder into the shell and compacting it in the radial direction, carried out by a pulsed magnetic field during periodic alternation of the powder compaction operation with the movement of the shell in a direction perpendicular to the pressing force [ one].

The main disadvantage of this method is its low productivity, which is due to the need for pre-fabrication of the shell (cutting a workpiece in the form of a pipe into segments of the required length), periodically-batch loading of the powder into the shell and periodic compaction of the powder in the shell by a pulsed magnetic field.

There is also known a method of forming lengthy products from powder materials, during which, at the preparatory stage of the process, the shell is made of tape, and filling its cavity with powder is combined in time with the manufacture of the shell, and a long reinforcing element in the form of a wire is introduced into the cavity of the shell. At the final stage of the process, the shell is heated, squeezed in the radial direction and subjected to heat treatment [2].

However, this method, being more productive than the one described above, has several significant drawbacks.

Firstly, this is not a sufficiently high rate of filling the shell with powder, since the powder enters the cavity of the shell by gravity, i.e. poured into it without any external impact on it. The result is not the highest possible process performance.

Secondly, this is the absence of any external effect on the powder already in the shell, as a result of which, at the stage of filling the shell with powder, its compaction occurs only under the influence of its own weight, and this negatively affects the porosity of the final product and the uniformity of its impregnation, t .e. on the quality of the finished product.

Thirdly, this is a limitation of the assortment of the resulting products in diameter (diameter not more than 15 mm), which is a consequence of the use of a rectilinear reinforcing element in the form of a single wire. In the manufacture of articles of large diameter (for example, more than 20 mm), one wire, due to the significant distance between its surface and the wall of the shell, does not provide a sufficient degree of uniformity in the impregnation of the product.

Fourth, this is a limitation of the assortment of products obtained by the number of materials with which the powder can be impregnated. In the known method, these are two metals: shell and reinforcing element.

In addition, a known method of forming lengthy products from powder materials, which due to the use of the energy of ultrasonic vibrations and a reinforcing element in the form of two wires does not have the above disadvantages.

According to this method, which includes the formation of a cylindrical shell and loading powder into its cavity, the implementation of which is carried out by rotational-translational movement of the tape through the neck of a funnel filled with powder and simultaneously introducing a reinforcing element from the wire into the cavity of the shell in the direction of its translational movement, to improve the quality of the finished product products and process performance, the reinforcing element is formed by two wires and act on it and on the powder, filling funnel, the ultrasonic vibration energy, wherein one of the wires of the reinforcing member attached to the spring shape and tell her rotational movement [3].

However, this method, which is the closest to the proposed and adopted as a prototype, has two significant drawbacks.

The first of these is that with an increase in the diameter of the manufactured products (for example, from 30 mm to 50 mm), which is very relevant, the distance between the coil of the spring and the inner surface of the shell increases and, therefore, the degree of uniformity of the impregnation decreases products. A similar phenomenon is observed in the area between the inner surface of the spring and the axis of the shell.

The second disadvantage of this method is interconnected with its technological capabilities and lies in the fact that it allows you to adjust the degree of impregnation of the product with the material of the reinforcing element only by changing the diameter of the wire used and changing the distance between the spring coils.

Due to these disadvantages, this method can be characterized as having limitations in technological capabilities and in the range of manufactured products in diameter.

The technical problem to which the invention is directed is to expand technological capabilities and increase the range of manufactured products.

To solve the problem in a method of ultrasonic molding of long products from powder materials, including simultaneously forming a hollow shell from a tape, filling the shell with powder material and introducing wire into its cavity, which is informed by ultrasonic frequency vibrations and by means of twisting, it gives the appearance of a spring, according to the invention, on the coils of the spring form protrusions.

The solution of the problem also contributes to the fact that:

- the formation of the protrusions is carried out mainly simultaneously with the twisting of the wire into the spring;

- the formation of the protrusions is carried out in a plane, mainly perpendicular to the longitudinal axis of the shell;

- the formation of the protrusions is carried out mainly on each coil of the spring;

- at least one protrusion is formed on the coil of the spring;

- the protrusion is formed so that its vertex is facing the longitudinal axis of symmetry of the shell or to its inner surface;

- the protrusions are formed so that their vertices are turned in one or in different directions;

- protrusions form with the same and / or with a different shape;

- the protrusions form with the same and / or with different sizes;

- the protrusion is formed with a height mainly exceeding the diameter of the wire.

The invention is illustrated by drawings:

figure 1 - shows the device by which the proposed method is implemented in any of the possible options for its implementation;

figure 2-4 shows a section along aa in figure 1 and shows the sequence of formation of the protrusions;

Figures 5-11 show embodiments of protrusions (to simplify the perception of the shape of the protrusions, the spring coils are conventionally shown to be linear).

The proposed method can be implemented by a device for ultrasonic molding of long products from powder materials 1, which (see Fig. 1) includes means for forming a hollow cylindrical shell 3 from a tape 2, consisting of a conical funnel 4 and a mechanism (in the drawings shown) for pulling the tape through the neck 5 of the funnel, i.e. through a cylindrical hole, and the feed mechanism into the cavity of the shell of a long reinforcing element of wire 6, which give the form of a spring 7.

The spring feed mechanism is formed, coaxially arranged, leading 8 and driven 9 rollers and a drive consisting of an electric motor 10 and a source 11 of ultrasonic vibrations. The leading 8 and driven rollers 9, having a cylindrical shape, are made (see FIG. 2), respectively, with longitudinal recesses 12 and with longitudinal beads 13, which, when the rollers rotate, are combined with each other and form (see FIG. 3) on the spring turns 7 the protrusions 14, separated from each other by radius sections 15. The recesses 12 and the flanges 13 can have a wide variety of shapes, dimensions and any options for their location, but they must necessarily provide the protrusions 14 with a certain height, which in its minimum value should and be larger than the diameter of the wire used. The optimal case is when the height of the protrusion is several times the diameter of the wire used.

The source of ultrasonic vibrations 11, located in the housing 16, is formed by a transformer 17 of the direction of oscillation, made in the form of a disk, and ultrasonic transducers 18, for example piezoceramic. The radiating link 19 of the oscillation direction transformer is rigidly connected to the waveguide 20 of the driving roller 8. They are a rod-type ultrasonic instrument, made as a whole and made of a titanium alloy. The transformer 17 of the direction of oscillation, its radiating link 19 and the waveguide 20, mounted along the symmetry axis of the funnel 4 and directly above its neck 5, are made with a through axial hole 21, which determines the possibility of the formation of a reinforcing element with two wires. To implement this feature, the device must have a second feed mechanism for this wire. An ultrasonic oscillation source 11 mounted rotatably around its longitudinal axis and reciprocating along it, and an electric motor 10 are interconnected by means of gears 22, 23 and 24.

The driven roller 9, made, for example, of textolite, is mounted on the funnel 4 by means of struts 25 and bracket 26 and is mounted with the possibility of rigid fixation in the working position (fixing screws are not shown in the drawings) and moving in directions perpendicular and parallel to the axis funnel symmetry.

The proposed method for ultrasonic molding of long products from powder materials, in its general form and in the form of forming a reinforcing element with one wire and giving it the appearance of a spring, is as follows.

First, prepare the device for operation. To do this, in the neck 5 of the funnel 4 through a rectangular hole (not indicated by figure 1) made in the side wall of the funnel, insert a thin metal strip 2 and twist it in a spiral, forming the first turns of a cylindrical shell 3, which are introduced into the neck 5 of the funnel and pass through it. Then, cutting the end of the tape, align the end of the shell 3 and close it with the lid 27. Then the driven 9 roller is moved away from the driving roller 8, the radiating end of the waveguide 20 of which is installed at some experimentally determined distance from the neck 5 of the funnel 4. After that, the cavity of the funnel through a round hole made in its wall (not indicated by figure 1), enter a thin wire 6. In this case, the free end of the wire (see figure 2) is placed between the leading 8 and the driven 9 rollers and hand squeeze it along surface riding roller. Then the driven roller (see figure 3) by means of racks 25 is pressed against the leading roller and rigidly fix its position. As a result of this movement, the shoulder 13 of the driven roller 9 presses the wire 6 into the recess 12 of the driving roller 8 and forms on it the first protrusion 14 of the future spring. After that, for a while, necessary for the spring 7 to touch the bottom of the cover 27 with its end, turn on the electric motor 10. As a result of this rotation, the first turns of the spring 7, equipped with the corresponding protrusions 14, are formed on the drive roller 8 (see Fig. 4). which are turned in one direction, made with the same shape and size, oriented in a plane perpendicular to the longitudinal axis of the shell, separated from each other by radius sections 15 and have a height exceeding the diameter of the wire 6. Then the cavity of the funnel 4 for fill with the necessary and pre-calculated amount of powder 1, which completes the preparation of the device for operation.

For the subsequent implementation of the process of forming a long workpiece, first turn on an ultrasonic generator (not shown), to which ultrasonic transducers 18 are connected, and then an electric motor 10 and a mechanism for pulling the tape 2 through the neck 5 of the funnel 4. As a result, the tape 2 is folded in a spiral, forming a shell 3 filled with powder 1, which at the entrance to the shell is exposed to ultrasonic vibrations by the end of the waveguide 20 of the driving roller 8. In the shell, the powder is densified It is due to the oscillations of the spring 7, performed by it (during its rotational and translational movements) with ultrasonic frequency, excited in it due to its contact with the side surface of the driving roller 8, which is an ultrasonic instrument.

At the end of the process of forming the workpiece of the required length, which can be judged, for example, by the complete expiration of the powder 1 from the funnel 4, the ultrasonic generator and the feeding mechanisms of the tape 2 and wire 6 are turned off. After that, the casing 3 and the spring 7 in the area located under the neck 5 funnels 4 are cut and a new lid 27 is installed on the end of the shell protruding from the neck of the funnel. Then, a new portion of the powder is poured into the funnel 4 and the next preform is formed.

The obtained preform, having previously provided it with a lid (corresponding to the shape and size of the lid 27), is first heated (if necessary) and crimped in the radial direction, and then subjected to heat treatment, as a result of which a finished product or a semi-finished product arriving at subsequent processing.

When implementing the proposed method, it is necessary to take into account that the degree and uniformity of the impregnation of the powder with the material of the reinforcing element is determined (see Figs. 5-11) by the size, shape, quantity, orientation and location of the protrusions 14, which can be very diverse and are set based on the requirements to finished products. A spring is quite optimal, the protrusions of which are shown in Figs. 8 and 11.

Other examples of the implementation of the proposed method include the possibility of forming protrusions on the wire until it starts to twist into a spring. This requires some structural complication of the equipment used, but it determines the possibility of arranging all the spring protrusions along the longitudinal axis of the shell or of arranging some part of them along the axis of the shell, and the other part perpendicular to it, which in some cases can be very practical.

The following is an example of a specific implementation of the proposed method, not excluding other options for its implementation in the scope of the claims.

When preparing the device for operation, a copper tape 2 (width 20 mm, thickness 0.25 mm) is inserted into the neck 5 of the funnel 4, having a diameter equal to 50.5 mm, and the progressive movement is manually reported to it. As a result of this, the tape in the counterclockwise direction of rotation is folded into a spiral and forms the first turns of the cylindrical shell 3. In this case, the introduction of the tape 2 is adjusted and set so that the overlap of the edges of the shell 3 having an internal diameter equal to 50 mm is 2 mm, and the angle of its rise was equal to 60 degrees. The feed of the tape is carried out manually until the first turn of the shell extends beyond the plane of the end face of the neck 5 of the funnel. Then, cutting the edge of the tape with scissors, align the end face of the shell 3 and close it with a lid 27.

After that, manipulating the location of the source of ultrasonic vibrations 11, racks 25 and bracket 26, install the leading 8 and driven 9 rollers. For this, the free (radiating) end of the waveguide 20 (diameter 14 mm, length 115 mm) of the driving roller 8 (diameter 34 mm, length 30 mm, recess 8 mm) is installed from the neck 5 of the funnel 4 at a distance of 15 mm, and the driven roller 9 (diameter 34 mm, length 30 mm, shoulder height 8 mm) are positioned so that its geometric center with the geometric center of waveguide 20 lies in the same plane, i.e. so that its lower end is located between the antinode of displacements and the antinode of stresses of the ultrasonic wave propagating in the waveguide.

Then, a copper wire 6 having a diameter of 2 mm is introduced into the cavity of the funnel 4 through an opening made in its wall. In this case, the free end of the wire (see figure 2) is placed between the leading 8 and the driven 9 rollers and hand squeeze it on the surface of the driving roller. Then the driven roller (see figure 3) by means of racks 25 is pressed against the leading roller and rigidly fix its position. As a result of this movement, the shoulder 13 of the driven roller 9 presses the wire 6 into the recess 12 of the driving roller 8 and forms on it the first protrusion 14 of the future spring (inner diameter of the radius sections 16 mm, pitch 6 mm). After that, for a while, it is necessary for the spring 7 to touch the bottom of the cover 27 with its end and turn on the electric motor 10. As a result of this rotation, the first turns of the spring 7, equipped with the corresponding protrusions 14, are formed on the drive roller 8 (see Fig. 4). which are turned in one direction, made with the same shape and size, oriented in a plane perpendicular to the longitudinal axis of the shell, separated from each other by equal radius sections 15 and have a height of 8 millimeters, which is four times the diameter of the wire.

After that, the cavity of the funnel 5 is filled with three kilograms of tungsten powder, as a result of which the emitting end of the waveguide 20 is immersed in the powder, and the preparation of the device for operation ends.

To carry out the process of forming a long workpiece, an ultrasonic generator is included, to which ultrasonic transducers 18, designed for a frequency of 19 kHz, are connected, an electric motor 10 and a mechanism for pulling the tape 2 through the neck 5 of the funnel 4. As a result, the tape 2 is twisted in a spiral and forms a sheath 3 performing rotational (30 rpm) and translational (0.85 cm / sec) movements and filled with powder 1, which when entering the shell 3 is exposed to ultrasonic vibrations emitted by the end face during novoda 20 and having an amplitude equal to 10 microns. In the cavity of the shell, the powder is compacted due to the oscillations of the spring 7, performed by it with ultrasonic frequency during its rotational (30 rpm) and translational (0.85 cm / sec) movements, which are excited in it due to its contact with the side surface drive roller 8, which is an ultrasonic instrument.

At the end of the process of forming the shell 3 of the required length, for example, a length of 100 cm, turn off the ultrasonic generator and the feed mechanisms of the tape 2 and wire 6. After that, the shell 3 and the spring 7 in the area located under the neck 5 of the funnel 4 are cut into the end of the shell, protruding from the neck of the funnel, put on the cover 27.

The shell made in this way is provided with a lid, heated to 850 degrees and subjected to rolling with a specific pressure of 6 t / cm. Then it is sintered in vacuum at a temperature of 1250 degrees and as a result an article is obtained having a porosity of 14-12% with an average degree of pore filling of 10-8.

A comparative analysis of the known and proposed methods of forming long products from powder materials shows significant advantages of the latter. So, for example, the proposed method allows to significantly increase the diameter of manufactured products (by more than 60%) and makes it possible to purposefully control the degree of impregnation of the product with the material of the reinforcing element, which is provided by varying the height of the protrusions, their number, shape and arrangement, i.e. the amount of material introduced in a particular area of the product.

Information sources

1. USSR author's certificate No. 428858, IPC B22F 3/02, 1975.

2. Copyright certificate of the USSR No. 997984, IPC B22F 3/02, 1981.

3. USSR author's certificate No. 1780923, IPC B22F 3/02, 1992.

Claims (9)

1. The method of ultrasonic molding of reinforced long products of powder materials, including the simultaneous molding of a tape of a hollow shell, filling the shell with powder material and introducing into its cavity a reinforcing element in the form of a wire, which is informed by fluctuations in the ultrasonic frequency and, by twisting, gives the form of a spring, characterized in that that protrusions with a height exceeding the diameter of the wire are formed on the coils of the spring or on the wire. 2. The method according to claim 1, characterized in that the protrusions form at the same time as the wire is twisted into a spring. 3. The method according to claim 2, characterized in that the protrusions are formed in a plane perpendicular to the longitudinal axis of the shell. 4. The method according to claim 2, characterized in that the protrusions form on each coil of the spring. 5. The method according to claim 2, characterized in that at least one protrusion is formed on the coil of the spring. 6. The method according to claim 2, characterized in that the protrusions are formed so that their vertices are facing the longitudinal axis of symmetry of the shell or its inner surface. 7. The method according to claim 1 or 2, characterized in that the protrusions are formed so that their vertices are turned in one or in different directions. 8. The method according to claim 1 or 2, characterized in that the protrusions form the same and / or different shapes. 9. The method according to claim 1 or 2, characterized in that the protrusions form with the same and / or with different sizes.

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