JPH0128801B2 - - Google Patents

Description

Claim 1 Spherical particles of metal powder are supplied to a rolling deformation device equipped with rolls, and the spherical particles are rolled in the rotational direction of the rolls and simultaneously stretched in the axial direction of the rolls to deform them and form metal fibers. In the method for making metal fibers, the stretching ratio of the spherical particles in the rotational axis direction is V ₃ , the radial reduction ratio of the spherical particles is V ₄ , the diameter of the spherical particles is D, and the diameter of the metal fiber is d In this case, the stretching ratio V ₃ in the rotational axis direction of the spherical particles is set to satisfy the relational expression V ₃ > 4/3・D ³ /d ³・V ₄ with respect to the radial reduction ratio V ₄ of the spherical particles. A method of making metal fibers characterized by:

2. The method according to claim 1, characterized in that the spherical particles are stretched along their axis of rotation and simultaneously moved in the plane of rolling in a direction perpendicular to the direction of operation.

3 having a supply passage, a supply mechanism for feeding spherical particles, and a first member and a second member consisting of rolls, the first member and the second member being spaced apart so as to simultaneously roll and stretch the spherical particles. and a device for stretching the spherical particles at a rate exceeding the metal plastic flow rate of the spherical particles while reducing the diameter of the spherical particles. A device for producing metal fibers in which the deformation device is controlled by a spherical particle stretching device.

4. One of the two bodies of the deformation tool serves as a means for stretching the spherical particle along its axis of rotation at a rate exceeding the plasticity rate of the metal at elongation during reduction of the diameter of the particle; One body has the form of an additional roll with a working surface made in the form of a rotating hyperbola of variable radius R(x), with the main roll and the additional roll having β between their axes. ＞arc tanD(2D ² −3d ² )(V ₁ −V ₂ )/12d ²・R・V ²
・sinα Here, V ₁ is the peripheral speed of the main roll, V ₂ is the peripheral speed of the additional roll, R is the radius at the center point of the operating surface of the main roll and additional roll, a is the spherical particle, the main roll and the additional roll 4. Device according to claim 3, characterized in that the device is placed intersectingly so that a contact angle of .

5 The working surface of the main roll has the shape of a rotating hyperbola with a variable radius R(x), and the intersection angle between the axis of the main roll and the axis of the additional roll is 2β>arc tanD(2D ² −3d ² )/6d ² ·R · sin α.

6 The variable radius R(x) of the rotating hyperbola is R(s) ^-√2 + ²・² , where x is the variable distance from the center point of the main roll and additional rolls to both sides along their axes. 6. A device according to claim 4, characterized in that it is defined by:

7. The means for stretching the spherical particles along their axis of rotation at a rate exceeding that of the plastic flow of the metal in the elongation during the reduction of the diameter of the particle may be an integral part of the main roll or of the deforming tool capable of reciprocating motion. 4. A device according to claim 3, characterized in that it has the form of a mechanism for imparting reciprocating motion mechanically coupled to the device.

8. Device according to claim 7, characterized in that one of the two bodies of the deformation tool has the form of an additional cylindrical roll.

9. Device according to claim 4 or 8, characterized in that the main roll of the deforming tool is cylindrical.

10 One of the two deformation tools is 70
10. Device according to claim 7 or 9, characterized in that it has the form of a flat plate inclined at ~80[deg.] and placed parallel to the axis of the horizontally placed main cylindrical roll.

11 The deformation tool is provided with a cylindrical part whose axis is horizontal, the surface 20 of this cylindrical part has a radius of curvature determined by 40D _nio ≦R ₁ ≦60D _nio , and this cylindrical part is connected to the upper end of the flat plate. and the mechanism for feeding the spherical particles extends 10-15° of an arc from the top point of said cylindrical surface towards the passage for feeding the spherical particles into the gap between the main cylindrical roll and said plate. shifted,
11. The device according to claim 10, wherein the diameter of each supply passage is made such that D ₁ ≦4D _nio , and the distance between adjacent passages is made such that l≧40D _nio .

[Detailed description of the invention]

[Technical Field of the Invention] The present invention relates to a powder metallurgy method for metal fibers used in gas and liquid filters and mixers, sound dampers, fire-resistant porous bodies, etc., and in particular, a method and apparatus for making metal fibers. Regarding.

[Technical background of the invention]

Current powder metallurgy processes require improved techniques and place high demands on cost efficiency and final product quality. Porous materials are of particular interest in powder metallurgy processes. One thing that seems very promising in this regard is the use of metal fibers instead of metal powders.
However, the widespread use of metal fibers in powder metallurgy is hampered by the lack of sufficiently simple and inexpensive manufacturing methods.

A basic solution to this problem is provided by mechanically processing the metal powder to obtain metal fibers directly from the metal powder.

A method for producing metal fibers from spherical particles of metal powder is known (see International Application PCT/SU-82/00030, filed September 15, 1982), in which spherical particles of metal powder are first supplied. These particles are then rolled in the operating channel and at the same time deformed by stretching (stretching) the particles along their axis of rotation, and the metal fibers thus produced are discharged.

The above-mentioned application further discloses an apparatus for making metal fibers from spherical particles of metal powder by the above-described method, the apparatus having a mechanism for feeding spherical particles and a deforming tool (or forming tool); The deformation tool has two main rolls that are placed opposite each other to roll and stretch the spherical particles to be deformed. The particles are then supplied into the gap between the two rolls from the supply passage of the supply mechanism.

However, the above method and apparatus are limited by the plasticity of the metal of the particles, and in order to obtain the maximum possible ratio between length and diameter of the fibers produced,
It has the disadvantage that an excessive number of rolling cycles are required, as a result of which the production efficiency is reduced and the plasticity of the metal of the particles is affected by the formation of cracks in the particles. The stretching of the variable-shaped spherical particles along the axis of rotation cannot completely neutralize the damping effect of the contact friction force directed toward the center of the fibers, which are made parallel to the axis of rotation; Deformation of the particles is hindered because the rate of such stretching cannot match the rate of plastic flow of the metal in the stretched state of the fiber.

[Summary of the invention]

The present invention aims to provide a method for making metal fibers, in which spherical particles of metal powder are rotated along the axis of their rotation to the maximum possible length and diameter of the fibers. The metal fibers are drawn at a rate that increases the manufacturing efficiency of the metal fibers. The present invention further aims to provide an apparatus for carrying out the method as described above,
This device has a structure that makes it possible to increase the production efficiency of metal fibers and to maximize the fiber length-to-diameter ratio.

In the method of the invention, spherical particles of metal powder are provided and these particles are deformed during the course of the manufacturing operation by rolling each particle and simultaneously stretching it along its axis of rotation; The metal fibers produced by the process are discharged. In the present invention, stretching the variable shape spherical particles of metal powder along its axis of rotation is carried out at a rate that exceeds the rate of plastic flow of the metal at elongation during reduction of the diameter of the spherical particles.

The degree to which the rate of elongation of the deformable particles is made greater than the rate of plastic flow of the metal during elongation while the particle diameter is reduced is preferably determined by the following formula: V ₃ >4/3·V ₄・D ³ /d ³ Here, V ₃ is the stretching ratio of the spherical particles along the rotation axis, V ₄ is the radial reduction ratio of the spherical particles, D is the diameter of the spherical particles, and d is the diameter of the metal fiber. be.

It is desirable to stretch the spherical particles along their axis of rotation while at the same time moving the particles in the rolling plane in a direction perpendicular to the path of the manufacturing operation.

The device according to the invention has a feeding mechanism with a feeding channel for feeding spherical particles and a deforming tool, said deforming tool consisting of a main body in the form of a main roll and a second body, both said bodies being flexible. The deformed spherical particles are placed opposite each other so as to be rolled and stretched at the same time, and the spherical particles are supplied into the gap between the two bodies from the supply passage of the supply mechanism. Further in the invention, means are coupled to the deforming tool for stretching each spherical particle along its axis of rotation at a rate exceeding the rate of plastic flow of the metal in the elongation during reduction of the diameter of the particle. .

Preferably, one body of the deformation tool serves as a means for stretching the spherical particle along its axis of rotation at a rate that exceeds the rate of plastic flow of the metal in the elongation during reduction of the diameter of the particle; The body has the form of an additional roll with a working surface made in the form of a rotating hyperbola of variable radius R(x), the main roll and the additional roll having an angle between their axes given by are crossed to form: β>arc tanD(2D ² −3d ² )(V ₁ −V ₂ )/12d ²・R・V ₂
・sinα Here, V ₁ is the peripheral speed of the main roll 2, V ₂ is the peripheral speed of the additional roll, R is the radius at the center point of the working surface of the main roll and additional roll, α is the spherical particle and the main and additional roll is the contact angle with

In addition, it is desirable that the operating surface of the main roll has the shape of a rotating hyperbola with a variable radius R(x). In this case, the intersection angle between the axis of the main roll and the axis of the additional roll is determined by the following formula: It is determined: 2β>arc tanD(2D ² −3d ² )/6d ² ·R·sinα Further, the variable radius R(x) of the rotating hyperbola is preferably determined by the following equation.

R(x)=√ ² + ² · ² where x is the variable distance from the center point along the axis of the main roll and additional rolls to both sides.

The means for stretching the spherical particles along their axis of rotation at a rate that exceeds the rate of plastic flow of the metal during elongation during the reduction in diameter of the particles is an integral part of the main roll or a reciprocating deformation tool. It is desirable to have some form of mechanism for imparting reciprocating motion mechanically coupled to the reciprocating motion.

Preferably, one body of the deformation tool has the form of an additional cylindrical roll.

Preferably, the main roll of the deformation tool has a cylindrical shape.

In another version, the deformation tool piece has the form of a flat plate inclined at 70-80° to the horizontal and placed parallel to the axis of the horizontally placed main cylindrical roll.

The deformation tool further has a cylindrical portion whose axis is horizontal, and the surface of this cylindrical portion has a radius of curvature defined by the following equation.

40D _nio ≦R ₁ ≦60D _nio It is desirable that this cylindrical part is connected to the upper end of the flat plate, and in this case, the mechanism for supplying spherical particles extends from the top of the cylindrical surface to the main cylindrical part. offset by 10-15° of an arc towards the passage for supplying particles into the gap between the roll and said plate;
The diameter of each supply passage is made to be D ₁ ≦4D _nio , and the distance between adjacent passages is made to be l≧40D _nio .

The invention makes it possible to increase the efficiency of fiber manufacturing operations, the fibers obtained by the method of the invention having the maximum possible ratio of length to diameter, which ratio is equal to that of the metal being deformed. It can be enlarged to the limit of plasticity.

[Embodiments of the invention]

In the method of making metal fibers from spherical particles of metal powder according to the present invention, the spherical particles are supplied,
These particles are deformed by rolling each of the particles in the direction of operation and simultaneously stretching them along their axis of rotation. The stretching of the spherical particles along the axis of rotation takes place at a rate greater than the rate of plastic flow of the metal at the time the diameter of the spherical particles being deformed is reduced.

The degree to which the elongation rate of the variable-shaped spherical particles of metal powder along the axis of rotation is greater than the rate of plastic flow of the metal in elongation when the diameter of the spherical particles is reduced is preferably determined by the following formula: : V ₃ > 4/3・V ₄・D ³ /d ³ Where, V ₃ is the stretching ratio of the spherical particles along the rotation axis, V ₄ is the radial reduction ratio of the spherical particles, and D is the reduction ratio of the spherical particles in the radial direction. diameter, d is the diameter of the metal fiber.

The stretching of the spherical particles along the axis of rotation to maximize the length of the metal fibers produced by the method of the invention is carried out by moving the particles in the plane of rolling in a direction perpendicular to the path of the manufacturing operation. be exposed.

FIG. 1 shows a device for carrying out the method of the invention, which device has a deforming tool 1, which is made up of two bodies made in the form of a main roll 2 and an additional roll 3. The additional roll 3 has a working surface in the form of a rotating hyperbola. What are roles 2 and 3?
Their axes 4 and 5 intersect and there is an angle β between them.
and β is determined from the following formula: β>arc tanD(2D ² −3d ² )(V ₁ −V ₂ )/12d ²・R・V ₂
・sinα Here, D is the diameter of the spherical particles 6, d is the diameter of the metal fiber 7, V ₁ is the linear velocity of the main roll 2, V ₂ is the linear velocity of the additional roll 3, and R is the working surface of the main roll 2. and the radius at the center point of the additional roll 3, α is the contact angle between the spherical particles 6 and the main and additional rolls 2 and 3.

The variable radius of the rotation hyperbola is determined from the following equation.

R(x) = √ ² + ²・² where x is main roll 2 or 14 and additional roll 3
are variable distances from their center points along the axes 4 and 5 on either side.

The apparatus according to the invention has means for stretching the spherical particles along its axis of rotation at a rate greater than the rate of plastic flow of the metal in the elongation during reduction of the diameter of the spherical particles, said additional rolls being It functions as a means of this.

FIG. 1 further shows the vectors of peripheral velocities V ₁ , V ₂ and tangential velocities V〓 ₁ , V〓 ₂ of rolls 2 and 3, respectively.

Spherical particles 6 of metal powder are fed from a feeding mechanism 8 through a passage 9 into the gap between the rolls 2 and 3, and metal fibers 7 exit from the opposite side of the rolls 2 and 3. Rolls 2 and 3 are held in bearings 10 and 11 and drive means 12 and 13 are connected to rolls 2 and 3.

FIG. 3 shows the directional vector of the frictional force τ at the contact point between the surface of the fiber 7 and the surface of the rolls 2, 3.

In another example of the device of the invention shown in FIG.
The working surface of the main roll 14 has the shape of a rotating hyperbola with a variable radius R(x) substantially similar to that described above. The angle between the axes 15 and 5 of the rolls 14 and 3 is determined by the following equation.

2β＞arc tanD(2D ² −3d ² )/6d ²・R・sinα Figures 4 and 5 show the main and additional rolls 1
4 and 3, the peripheral velocity vectors V ₁ , V ₂ and the tangential velocity vectors V〓 ₁ , V〓 ₂ are shown.

In a further embodiment of the device according to the invention, the second body of the deforming tool 1 is made in the form of a cylindrical roll 16, as shown in FIG. Means for stretching a variable shape spherical particle of metal powder along its axis of rotation at a rate greater than the rate of plastic flow of the metal in the elongation during which the diameter of said particle is reduced comprises a bearing 1
Mechanism 1 that provides reciprocating motion to a roll 2 connected to
It is 7.

FIG. 7 shows vectors of peripheral speeds of the main and additional rolls 2 and 16 of the deforming tool 1 shown in FIG.
Indicates V ₁ and V ₂ .

In another embodiment of the device according to the invention, shown in FIGS. 8 and 9, the second body of the deforming tool 1 is a flat plate 18.
This roll 18 is placed parallel to the axis 4 of a cylindrical main roll 2 placed horizontally so as to form an angle of 70 degrees with the horizontal.

In the final example of the device of the invention shown in FIG. 10, the deforming tool 1 has a cylindrical section with a horizontal axis, and the surface 20 has a radius of curvature R ₁ defined by the following equation: connected to.

Mechanism 8 for supplying spherical particles of 40D _nio ≦R ₁ ≦60D _nio metal powder
is offset slightly at an angle of 15° from the uppermost point of surface 20 towards the path of rolling the particles 6 between roll 2 and plate 19. The diameter of each passage 9 for supplying spherical particles is D ₁ ≦4D _nio , and adjacent passages are separated by a distance of l≧40D _nio .

The apparatus for carrying out the method of the invention shown in FIGS. 1, 2 and 3 operates as follows.

Drive means 12 and 13 are engaged to rotate the main cylindrical roll 2 and the additional roll 3 in one direction but at different peripheral speeds V ₁ and V ₂ . Spherical particles 6 of metal powder are fed from a feed mechanism 8 through a channel 9 into the gap between the rolls 2 and 3 of the forming tool 1. By giving roll 2 a peripheral velocity V ₁ that is higher than the peripheral velocity V ₂ of roll 3, it is possible to draw the particles 6 into the gap between rolls 2 and 3 during rolling and then transport them along the operating path. be made into While being moved in the direction of the fiber manufacturing operation in the gap between rolls 2 and 3, the particles 6 are deformed by rolling and stretching. The stretching is carried out at a rate greater than the rate of plastic flow of the metal at elongation when the diameter of the particle 6 is reduced, which rate is given by the equation:

V ₃ >4/3・V ₄・D ³ /d ³ Where, V ₃ is the stretching ratio of the spherical particles 6 along the rotation axis, V ₄ is the radial reduction ratio of the spherical particles 6, and D is the spherical particle. 6 is the diameter, and d is the diameter of the metal fiber 7.

The particles 6 are deformed until fibers 7 are created, the diameter of these fibers depending on the minimum gap between the rolls 2 and 3.

The axis 5 of the roll 3 is inclined with respect to the axis 4 of the roll 2 by an angle determined by the following equation.

β＞arc tanD(2D ² −3d ² )(V ₁ −V ₂ )/12d ²・R・V ₂
・sinα Here, R is the radius of the working surface of the main roll 2 and additional roll 3 measured at the center point of these rolls, α is the contact angle between the spherical particles 6 and rolls 2 and 3, and rolls 2 and 3. Since _the mother surfaces of _both rolls are parallel in the area where the _gap between
Stretching along the axis of rotation is facilitated. The value of V〓 ₂ increases as the inclination angle β of the axes 4 and 5 of the rolls 2 and 3 increases. Tangential component V of peripheral velocity V ₁ of roll 2 ₁ is 0 (zero)
Therefore, the axes 4 and 5 of rolls 2 and 3
By changing the inclination angle β of rolls 2 and 3
The contact friction force τ on the top is directed in the opposite direction, so that the particles 6 are stretched by the contact friction force τ in the direction of the tangential component V〓 _{2 of the peripheral velocity V 2} of the roll 3, and the particle ₆ is stretched by the contact friction force τ in the direction of the tangential component _V〓 Since the value is greater than the rate of plastic flow of the metal in elongation when the diameter of the particles 6 is reduced, this facilitates the formation of the fibers 7. This increases the efficiency of operation.

The apparatus shown in FIGS. 4 and 5 operates as follows.

The apparatus is started and the particles 6 are fed into the gap between the main roll 14 and the additional roll 3 as described above.
The axis 15 of the roll 14 is aligned with the axis 5 of the roll 3 at an angle determined by the following formula: 2β>arc tanD(2D ² −3d ² )/6d ²・R・sinα. Although the generatrix lines of these rolls 14 and 3 are kept in parallel positions, the tangential component V〓 ₁ of the peripheral velocity V ₁ is tilted in the plane emerging from the gap between them. Component V〓 is directed to the same side as ₂ . The difference between these components V〓 ₁ and V〓 ₂ generates a force that stretches the particle 6 in a direction coinciding with its axis of rotation. component in order to neutralize the contact friction force in the direction of stretching of the particles 6 by varying the value of the angle 2β between the rolls 14 and 3.
The difference between V〓 ₁ and V〓 ₂ is chosen to be greater than the rate of plastic flow of the metal in the elongation when the diameter of the particle 6 is reduced. Velocity vector V〓 ₁ and V〓 ₂
Due to the same direction of the particles 6, each particle 6 is moved along the generatrix of the rolls 14 and 3 with a speed V 〓 ₂ during their deformation, so that the particles 6 are moved along their axis of rotation. distributed. This prevents adjacent particles 6 from overlapping in the direction of their extension, facilitating the operation of forming the fibers 7 and increasing the efficiency of the operation.

The apparatus shown in FIGS. 6 and 7 operates as follows.

The drive means 12 and 13 are actuated to rotate the main and additional cylindrical rolls 2 and 16 in the same direction but at different speeds V ₁ and V ₂ . At the same time, a mechanism for imparting reciprocating motion to the roll 2 is actuated, and this motion is transferred to the link mechanism and the bearing 10.
The information is transmitted to role 2 via . In other respects the device functions as described above. The shape of rolls 2 and 16 allows for easy fabrication, and rolls 2 and 16
The axial reciprocating motion provided to facilitates shaping of the fiber 7 and increases the speed of the fiber manufacturing operation.

The apparatus shown in FIGS. 8 and 9 operates as follows.

The drive means 12 is actuated to rotate the roll 2 in the operating direction, and at the same time the mechanism 17 is actuated so that an axial reciprocating motion is transmitted from the mechanism 17 to the roll 2 via the bearing 10. Particles 6 are fed between roll 2 and plate 18 of deformation tool 1 . The angle of inclination of the plate 18 with respect to the horizontal is 70-80°. Reducing the angle between plate 18 and the horizontal reduces the rate at which particles are fed between plate 18 and roll 2, which affects the efficiency of the device. In other respects the device functions as described for the previous example.

In order to improve the distribution of the particles 6 fed from the mechanism 8 into the gap between the roll 2 and the plate 19 (FIG. 10), these particles 6 are transferred from the passage 9 to the cylindrical surface 2.
0, falls freely onto this surface and is dispersed after impacting this surface 20.

The provision of a cylindrical surface 20 at the upper end of the plate 19 allows the mechanism 8 to be used to supply particles 6 with different diameters.

As described above, according to the present invention, spherical particles of metal powder are stretched along their rotation axis at a rate exceeding the plastic flow rate of the metal during elongation during reduction of the diameter of the spherical particles. The metal fibers made are commercially available because they give the maximum possible ratio of length to diameter of the fibers, increase the production efficiency of the metal fibers, and allow drawing to be carried out without cracking the spherical particles of metal powder. It is of good quality.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the apparatus for producing metal fibers according to the present invention, that is, an example in which the deforming tool is made as an additional roll having an operating surface of a rotating hyperbola, and FIG. FIG. 3 is a sectional view taken along the line - in FIG. FIG. 5 is a sectional view taken along the line - in FIG. 4, FIG. 6 is an explanatory view of the other side of the device of the present invention, that is, an example in which a mechanism for giving reciprocating motion is provided, and FIG. 7 is a cross-sectional view taken along the line - in FIG. 6, FIG. 8 is an explanatory diagram of still another example of the device of the present invention, that is, an example in which the second body of the deforming tool is made as a plate, and FIG.
The figure is a view taken by arrow A in Fig. 8, and Fig. 10 is a view taken from arrow A in Fig. 8.
FIG. 3 is a perspective view according to arrow B in the figure. 1... Deformation tool, 2... Main roll, 3... Additional roll, 4, 5... Axis center of rolls 2 and 3, 6
... Spherical particles, 7 ... Metal fibers, 12,13 ...
Drive means, 17...means for giving reciprocating motion.