CN117300128A

CN117300128A - A centrifugal disk that can throw out molten metal droplets radially

Info

Publication number: CN117300128A
Application number: CN202311276118.2A
Authority: CN
Inventors: 魏世忠; 李鹏; 雷贤卿; 杨璐; 孙波; 仝帅武; 毛丰; 王军令
Original assignee: Henan University of Science and Technology
Current assignee: Henan University of Science and Technology
Priority date: 2023-09-29
Filing date: 2023-09-29
Publication date: 2023-12-29

Abstract

A centrifugal disk capable of radially throwing out metal molten drops, wherein a plurality of liquid throwing grooves are uniformly distributed on the disk surface of the centrifugal disk along the circumferential direction, and the center line of each liquid throwing groove is a section of logarithmic spiral line taking the center of the disk surface as the center; the center of the disk surface is provided with a molten pool, when the centrifugal disk works, the rotating direction of the centrifugal disk is opposite to the outward extending direction of the logarithmic spiral line, and metal molten in the molten pool enters each liquid throwing groove and is thrown out along the radial direction of the centrifugal disk at the tail end of each liquid throwing groove. Because of the forward impact, the molten drops are directly fused with the deposition layer after impacting the deposition layer, and reflection cannot occur, so that the problem that the reflected molten drops impact the deposition layer again is solved from the source. Compared with oblique impact, the front impact in the radial direction is beneficial to improving the fusion density of the molten drops and the deposition layer and forming fine grain structures, and the molten drops can be almost completely fused on the deposition layer, so that the effective deposition rate of the metal material is greatly improved.

Description

Centrifugal disk capable of radially throwing out metal molten drops

Technical Field

The invention relates to the technical field of centrifugal spray forming, in particular to a centrifugal disk capable of radially throwing out metal molten drops.

Background

The principle of spray deposition is that under the protection of inert gas, molten metal is broken into tiny metal droplets, then the fine metal droplets are continuously sprayed onto a metal substrate under the action of high-pressure gas or centrifugal force to deposit a semi-solidified deposition layer, the deposition layer is solidified into a prefabricated blank by means of heat conduction of the metal substrate, and the prefabricated blank is subjected to hot extrusion or hot forging to form a high-density metal ring body. The spray deposition process has the advantages that annular parts with small component segregation degree, fine and uniform structure and larger size can be prepared.

The invention patent with the publication number of CN109877299B discloses a cast-in device and a cast-in centrifugal disc, wherein the cast-in device in the patent realizes the preparation of a metal hollow ingot by using a jet deposition principle. However, in the application, the prepared metal hollow ingot is not ideal, and mainly has the characteristics of insufficient fine grain structure and insufficient high density.

It has been found by analysis that one reason for the insufficient fineness and low density of the grain structure is that the molten droplets thrown from the centrifugal disk are not thrown at a high enough speed, and the impact kinetic energy is not large enough, so that smaller dendrites cannot be formed by impact. In the existing centrifugal disk, even if the rotating speed is increased to more than 1 ten thousand revolutions per minute, the throwing speed of the molten drops is not increased obviously. As shown in fig. 1, the reason for this is that the droplet 4 thrown out of the melt pool 11 has a small velocity, and the droplet 4 is caused to bounce and roll on the disk surface of the centrifugal disk 1, so that the throwing-out velocity of the droplet 4 is not high enough and the kinetic energy is not large enough. For this purpose, radial grooves 16 are provided in the disk surface of the centrifugal disk 1, see fig. 2-3. The droplets 4 enter the radial slots 16 and move outwardly along the radial slots 16 and are thrown outwardly at the ends of the radial slots 16. Obviously, the radial grooves 16 can prevent the molten drops 4 from bouncing and rolling on the centrifugal disk 1, so that the molten drops 4 reach the same angular velocity as the centrifugal disk 1 before being separated from the centrifugal disk 1, and the throwing speed and the kinetic energy of the molten drops 4 are improved.

Another reason for the insufficient fineness and low density of the grain structure is that the droplets 4 thrown from the centrifugal disk 1 do not strike the deposit 3 in the radial direction but strike the deposit 3 in an oblique direction. As can be seen from fig. 3, the droplets 4, after being thrown out of the radial grooves 16, strike the deposit layer 3 obliquely, and the deposit layer 3 is deposited on the metal substrate 2. According to the requirements of the spray forming process, the molten droplets 4 need to be rapidly cooled during the throwing process, and are required to be in a semi-solidified state before striking the deposited layer 3. In this way, the droplet 4 in the semi-solidified state will reflect when it hits the deposit 3, only a part of the droplet 4 being fused to the deposit 3 and another part of the droplet 4 being reflected. If the reflected droplets 4 no longer strike the deposit 3, only material losses are caused, but most of the droplets 4 strike the deposit 3 again after reflection by the centrifugal disk 1. Because the molten drops after multiple impacts lose part of kinetic energy and solidify gradually, after impacting the deposit again, on one hand, the fusion property of the molten drops and the deposit is poor, the tissue is loose, and the density is affected; on the other hand, smaller dendrites cannot be formed. In summary, it is critical to solve the problem that it is desirable to be able to strike the droplets against the deposit layer in the radial front of the centrifuge disk, thereby eliminating the possibility of droplet reflection from the source.

Disclosure of Invention

In order to overcome the defects in the background technology, the invention discloses a centrifugal disk capable of radially throwing out metal molten drops, which aims at: the molten drops can strike the deposition layer along the radial front surface of the centrifugal disk, and the possibility of reflection of the molten drops is eliminated from the source.

In order to achieve the aim of the invention, the invention adopts the following technical scheme:

a centrifugal disk capable of radially throwing out metal molten drops, wherein a plurality of liquid throwing grooves are uniformly distributed on the disk surface of the centrifugal disk along the circumferential direction, and the center line of each liquid throwing groove is a section of logarithmic spiral line taking the center of the disk surface as the center; the center of the disk surface is provided with a molten pool, when the centrifugal disk works, the rotating direction of the centrifugal disk is opposite to the outward extending direction of the logarithmic spiral line, and metal molten in the molten pool enters each liquid throwing groove and is thrown out along the radial direction of the centrifugal disk at the tail end of each liquid throwing groove.

After the technical scheme is implemented, the following beneficial effects can be generated:

1. the central line is a liquid throwing groove with a logarithmic spiral line, so that molten drops can be thrown out from the centrifugal disk in a radial direction and impact a deposition layer. Due to the front impact in the radial direction, the molten drops are directly fused with the deposition layer after impacting the deposition layer, a small amount of sputtering is likely to occur, but reflection cannot occur, so that the problem that the reflected molten drops impact the deposition layer again is solved from the source.

2. The front impact in the radial direction is beneficial to improving the fusion density of the molten drops and the deposition layer and forming fine grain structures, and the molten drops can be almost completely fused on the deposition layer, so that the effective deposition rate of the metal material is greatly improved.

3. In operation, the droplets are moved in the spinning tank by a logarithmic spiral, which is independent of the rotational speed, i.e. the droplets are always spun out in the radial direction of the centrifugal disk, whether the rotational speed of the centrifugal disk is high or low.

Further improving the technical scheme, the expression of the logarithmic spiral is as follows:

r＝R*e ^θ ；

wherein R is the polar diameter, R is the radius of the melt pool, θ is the polar angle, and θ > pi.

After implementing the technical scheme, the beneficial effects that it produced are: the polar angle theta is larger than pi, the rigidity of the logarithmic spiral line can be increased, and the centrifugal acceleration of the molten drop can be increased exponentially along with the polar angle theta.

According to the technical scheme, a liquid outlet hole is formed between the molten pool and the liquid throwing groove, and when the liquid throwing groove works, metal molten in the molten pool enters each liquid throwing groove through the liquid outlet hole.

After implementing the technical scheme, the beneficial effects that it produced are: the liquid outlet hole is equivalent to a limiting hole, so that excessive molten metal can be prevented from entering the liquid throwing groove to form molten drops with overlarge diameters.

According to the technical scheme, a conical surface which is inclined downwards is arranged at the edge of the centrifugal disc, when the centrifugal disc works, molten drops impact the deposited layer and then are reflected, and after the molten drops impact the conical surface, the reflected molten drops are reflected downwards by the conical surface.

After implementing the technical scheme, the beneficial effects that it produced are: the impact movement is complicated, and there may be a small amount of molten droplets that are reflected after striking the deposit, and then strike the deposit again by reflection from the centrifugal disk. After the conical surface is arranged, the molten drops can be reflected downwards and do not strike the deposition layer any more.

According to the technical scheme, the edge of the centrifugal disk is wrapped with the hot-melt material, when the centrifugal disk works, molten drops impact the deposition layer and then are reflected, and the reflected molten drops are absorbed by the hot-melt material after impacting the hot-melt material.

After implementing the technical scheme, the beneficial effects that it produced are: the metal molten drop is a high-heat liquid drop, and when striking the hot-melt material, the molten drop can instantly soften the hot-melt material, and at the moment, the molten drop is embedded or penetrated into the hot-melt material, so that the possibility of reflection is lost. Thus, the problem that the reflected molten drops strike the deposited layer again is fundamentally solved.

Further improving the technical scheme, the hot-melt material is any one of asphalt, plastic and hot-melt adhesive.

After implementing the technical scheme, the beneficial effects that it produced are: asphalt, plastic, hot melt adhesive and the like are common hot melt materials and can be wrapped at the edge of the centrifugal disc.

Drawings

Fig. 1 shows a schematic structure of a conventional centrifugal disk.

Fig. 2 shows a schematic structure of a conventional centrifugal disk with radial grooves.

Fig. 3 shows a top view of fig. 2.

Fig. 4 shows a schematic perspective view of the centrifugal disk.

Figure 5 shows a diagram of the movement analysis of the pellets in the radial grooves.

Fig. 6 shows a diagram of the trajectory of the movement of the pellet in the logarithmic spiral groove at time T1.

Fig. 7 shows a diagram of the trajectory of the movement of the pellet in the logarithmic spiral groove at time T21.

Figure 8 shows a graph of the movement analysis of the pellets in a logarithmic spiral groove.

Fig. 9-11 show a schematic representation of a modification of the present centrifuge disk.

In the figure:

1. a centrifugal disc;

11. a melt pool; 12. a liquid throwing tank; 13. a liquid outlet hole; 14. conical surface; 15. a hot-melt material; 16. a radial groove;

2. a metal substrate;

3. depositing a layer;

4. dripping;

5. and (3) a small ball.

Detailed Description

Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention. It should be noted that, in the description of the present invention, terms such as "front", "rear", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", and the like indicate directions or positional relationships based on the directions or positional relationships shown in the drawings, which are merely for convenience of description, and do not indicate or imply that the devices or elements must have a specific orientation, be constructed and operated in a specific orientation, and thus are not to be construed as limiting the present invention. It should also be noted that, in the description of the present invention, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; either directly or indirectly through intermediaries, or in communication with each other. The specific meaning of the above terms in the present invention can be understood by those skilled in the art according to the specific circumstances.

As shown in fig. 4, a centrifugal disk capable of radially throwing out metal molten drops is characterized in that ten liquid throwing grooves 12 are uniformly distributed on the disk surface of the centrifugal disk 1 along the circumferential direction, and the center line of each liquid throwing groove 12 is a section of logarithmic spiral line taking the center of the disk surface as the center. A melt pool 11 is arranged in the center of the disk surface, and the melt pool 11 is connected with ten liquid throwing tanks 12.

If the movement of the droplet 4 in the slinger 12 is to be studied, the trajectory of the movement of the ball 5 in the radial groove 16 must be studied first.

Refer to fig. 5. When the centrifugal disk 1 rotates counterclockwise, the ball 5 is subjected to two forces in the radial groove 16, one being the thrust Ft of the radial groove 16 against the ball 5 and the other being the centrifugal force Fr. The resultant force of the thrust force Ft and the centrifugal force Fr is F, the direction of which is inclined, and the angle between which and the radial line is α.

Similarly, the pellet 5 generates two speeds, one being the speed Vt in the circumferential direction, the direction of Vt being the same as the thrust Ft, the magnitude of Vt being related to the rotational speed of the centrifugal disk 1 and the position of the pellet 5; the other is the radial velocity Vr, the direction of which is the same as the centrifugal force Fr, and the magnitude of which is related to the centrifugal force Fr. Vt and Vt composite velocity are V, the direction of composite velocity V is inclined, and the included angle between the composite velocity V and the radial line is alpha. This means that the pellets 5 will be thrown out of the radial groove 16 in an inclined direction.

If viewed standing on the centrifugal disk 1, the pellets 5 simply make an acceleration-varying linear movement in the radial grooves 16 with increasing radius. If viewed outside the centrifugal disk 1, the pellets 5 do not only an accelerated linear movement in the radial grooves 16, but also a circular movement in circumferential direction with increasing rotational speed with radius. Thus, the movement track of the small ball 5 on the centrifugal disk 1 is a logarithmic spiral line which takes the center of the disk surface as the center.

According to the nature of the logarithmic spiral, the angle between the tangent line at any point on the spiral and the radial line is equal, so that the angle alpha between the resultant force F and the radial line is unchanged, and the angle alpha between the synthetic speed V and the radial line is also unchanged. For logarithmic spiral the formula r=r×e ^θ When θ > pi, vr≡Vt and Ft≡Fr. At this time, α is about 45 °. In addition, the polar angle theta is larger than pi, and the rigidity of the logarithmic spiral line can be increasedAnd the centrifugal acceleration of the pellets 5 increases exponentially with the polar angle θ.

Then, in another approach, the reference object can be translated. If a liquid throwing groove 12 with a central line of a logarithmic spiral line is arranged on the centrifugal disk 1, a small ball 5 with zero initial speed is placed at the inner end of the liquid throwing groove 12, and then the centrifugal disk 1 is rotated clockwise, the movement track of the small ball 5 in the liquid throwing groove 12 is a logarithmic spiral line when the centrifugal disk 1 stands outside the centrifugal disk 1.

Refer to fig. 6. At time T1, when the pellet 5 is positioned in the virtual radial groove 16, the pellet 5 is positioned at point P1 in the logarithmic spiral groove when the pellet is viewed as standing outside the centrifugal disk 1.

Refer to fig. 7. At time T2, when the ball 5 is observed to move to point P2 in the logarithmic spiral groove when standing outside the centrifugal disk 1, the ball 5 is still located in the virtual radial groove 16.

Thus, when viewed outside the centrifugal disk 1, the ball 5 moves in a linear acceleration-varying manner with increasing radius, corresponding to a radial groove 16 which does not rotate, the angle of the radial groove 16 being dependent on the starting position of the ball 5. This means that the pellets 5 are thrown out in the radial direction of the centrifugal disk 1.

Refer to fig. 8. Since the centrifugal disk 1 turns, the direction of Vt and thrust Ft is reversed, and the resultant speed of Vt and V is Vr, and the resultant force of Ft and F is Fr. The ball 5 is thrown out at a reduced speed compared to the movement of the ball 5 in the radial groove 16.

For the present invention, the droplet 4 corresponds to the pellet 5, and the movement locus of the droplet 4 in the liquid throwing groove 12 is a straight line when viewed from the outside of the centrifugal disk 1, and the straight line is a radial line of the centrifugal disk 1. The droplets 4 can be thrown out in the radial direction of the centrifugal disk 1, impinging positively on the deposit 3. Due to the forward impact, the molten drops 4 are directly fused with the deposition layer 3 after impacting the deposition layer 3, a small amount of sputtering is possible, but reflection cannot occur, so that the problem that the reflected molten drops 4 impact the deposition layer 3 again is solved from the source. Compared with oblique impact, the front impact in the radial direction is beneficial to improving the fusion density of the molten drops 4 and the deposition layer 3 and forming fine grain structures, and the molten drops 4 can be almost completely fused on the deposition layer 3, so that the effective deposition rate of the metal material is greatly improved.

Furthermore, the movement of the droplet 4 in the slinger 12 is independent of the rotational speed. That is, the droplets 4 can always be thrown out in the radial direction of the centrifugal disk 1, regardless of whether the rotational speed of the centrifugal disk 1 is large or small.

Refer to fig. 9. In one improvement scheme, the molten pool 11 is a cylinder, a plurality of liquid outlet holes 13 are formed in the cylinder wall, and when the device works, metal molten in the molten pool 11 enters each liquid throwing groove 12 through the liquid outlet holes 13. The liquid outlet hole 13 is equivalent to a flow limiting hole, and can prevent excessive molten metal from entering the liquid throwing groove 12 to form molten drops 4 with oversized diameter.

Referring to fig. 10. In another improvement, a conical surface 14 inclined downwards is arranged at the edge of the centrifugal disk 1, when the centrifugal disk works, the molten drops 4 strike the deposition layer 3 and then are reflected, and after striking the conical surface 14, the reflected molten drops 4 are reflected downwards by the conical surface 14.

The impact process is complicated and there may be a small amount of droplets 4 that are reflected after striking the deposit 3 and then strike the deposit 3 again by reflection from the centrifugal disk 1. After the conical surface 14 is arranged, the molten drops 4 can be reflected downwards to fall into the bottom of the box and no longer strike the deposition layer 3. The droplets 4 falling into the bottom of the tank can also be reused after cooling.

Referring to fig. 11, the edge of the centrifugal disk 1 may be coated with a hot-melt material 15, and when in operation, the molten droplets 4 strike the deposit layer 3 and then reflect, and the reflected molten droplets 4 are absorbed by the hot-melt material 15 after striking the hot-melt material 15. The hot melt material 15 may be any of asphalt, plastic, and hot melt adhesive. Asphalt, plastic, hot melt adhesive, etc. are common hot melt materials 15 that can be wound around the edge of the centrifuge disk 1.

The metal droplets 4 are high-heat droplets, and the droplets 4 can soften the hot-melt material 15 instantaneously when striking the hot-melt material 15, and the droplets 4 will be embedded or penetrated into the hot-melt material 15 to lose the possibility of reflection. This fundamentally solves the problem of the reflective droplet 4 striking the deposited layer 3 again.

The hot-melt material needs to be replaced periodically, and the replaced hot-melt material contains solidified metal material. In order to recover the metal material, the hot-melt material may be removed by a hot-melt method, and the metal material may be filtered out.

The parts not described in detail are prior art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.

Claims

1. A centrifugal disk capable of radially throwing out metal molten drops is characterized in that: a plurality of liquid throwing grooves are uniformly distributed on the disk surface of the centrifugal disk along the circumferential direction, and the center line of each liquid throwing groove is a section of logarithmic spiral line taking the center of the disk surface as the center; the center of the disk surface is provided with a molten pool, when the centrifugal disk works, the rotating direction of the centrifugal disk is opposite to the outward extending direction of the logarithmic spiral line, and metal molten in the molten pool enters each liquid throwing groove and is thrown out along the radial direction of the centrifugal disk at the tail end of each liquid throwing groove.

2. A centrifugal disk for radially projecting molten metal droplets according to claim 1, wherein: the expression of the logarithmic spiral is: r=r×e ^θ ；

3. A centrifugal disk for radially projecting molten metal droplets according to claim 1, wherein: a liquid outlet is arranged between the molten pool and the liquid throwing groove, and when the liquid throwing groove works, metal molten in the molten pool enters each liquid throwing groove through the liquid outlet.

4. A centrifugal disk for radially projecting molten metal droplets according to claim 1, wherein: the edge of the centrifugal disk is provided with a conical surface which is inclined downwards, when the centrifugal disk works, the molten drops impact the deposition layer and then are reflected, and after the molten drops impact the conical surface, the reflected molten drops are reflected downwards by the conical surface.

5. A centrifugal disk for radially projecting molten metal droplets according to claim 1, wherein: the edge of the centrifugal disk is wrapped with a hot-melt material, when the centrifugal disk works, molten drops impact the deposition layer and then are reflected, and the reflected molten drops are absorbed by the hot-melt material after impacting the hot-melt material.

6. A centrifugal disk for radially projecting molten metal droplets according to claim 5, wherein: the hot-melt material is any one of asphalt, plastic and hot-melt adhesive.