A centrifugal disc for flinging off molten metal droplets radially

Abstract

A centrifugal disc capable of throwing out metal droplets in radial direction is provided with a plurality of liquid throwing grooves along the circumference of the disc surface, the center line of the liquid throwing grooves being a logarithmic spiral with the center of the disc surface as the center; a molten liquid pool is arranged at the center of the disc surface; during operation, the rotating direction of the centrifugal disc is opposite to the outward extending direction of the logarithmic spiral; the metal molten liquid in the molten liquid pool enters into each liquid throwing groove and is thrown out in the radial direction of the centrifugal disc at the end of each liquid throwing groove. Since the impact is direct, the molten droplets directly fuse with the deposited layer after impacting the deposited layer and do not reflect, thus solving the problem of the reflected molten droplets impacting the deposited layer again from the source. Compared with the oblique impact, the direct impact in the radial direction is not only beneficial to improving the density of the molten droplets and the deposited layer and forming fine grain structure, but also enables the molten droplets to almost completely fuse on the deposited layer, greatly improving the effective deposition rate of the metal material.

Description

Technical Field

[0001] This invention relates to the field of centrifugal jet forming technology, and in particular to a centrifugal disc capable of radially ejecting molten metal droplets. Background Technology

[0002] The principle of spray deposition is to break molten metal into fine droplets under the protection of an inert gas, and then continuously spray them onto a metal substrate under high pressure or centrifugal force, depositing a semi-solid deposition layer. The deposition layer solidifies into a preform through thermal conduction from the metal substrate. The preform is then hot-extruded or hot-forged to form a high-density metal ring. The advantage of spray deposition is that it can produce ring-shaped parts with minimal compositional segregation, fine and uniform microstructure, and relatively large dimensions.

[0003] The invention patent with authorization announcement number CN109877299B discloses a casting device and a casting centrifugal disc. The casting device in this patent uses the jet deposition principle to prepare hollow metal ingots. However, in application, it was found that the prepared hollow metal ingots are not ideal, mainly because the grain structure is not fine enough and the density is not high enough.

[0004] Analysis revealed that one reason for the insufficiently fine grain size and low density is that the ejection velocity of the molten droplets from the centrifuge disc is not high enough, and the impact kinetic energy is also insufficient to form smaller dendrites through impact. Even with increases in rotational speed to over 10,000 revolutions per minute, the ejection velocity of the molten droplets in existing centrifuge discs has not significantly improved. Figure 1 As shown, the reason is that the molten droplets 4 ejected from the molten pool 11 have a relatively low velocity, and they bounce and roll on the surface of the centrifugal disk 1, resulting in insufficient ejection velocity and kinetic energy. Therefore, radial grooves 16 are provided on the surface of the centrifugal disk 1, referring to... Figure 2-3 After entering the radial groove 16, the molten droplet 4 moves outward along the radial groove 16 and is thrown outward at the end of the radial groove 16. Obviously, the radial groove 16 can prevent the molten droplet 4 from bouncing and rolling on the centrifugal disk 1, so that the molten droplet 4 reaches the same angular velocity as the centrifugal disk 1 before leaving the centrifugal disk 1, which is beneficial to improving the throwing speed and kinetic energy of the molten droplet 4.

[0005] Another reason for the insufficiently fine grain structure and low density is that the molten droplets 4 ejected from the centrifuge disc 1 do not impact the deposition layer 3 radially, but rather obliquely. Figure 3As can be seen, after being ejected from the radial groove 16, the molten droplet 4 obliquely impacts the deposition layer 3, which is deposited on the metal substrate 2. According to the requirements of the spray forming process, the molten droplet 4 needs to cool rapidly during ejection, reaching a semi-solid state before impacting the deposition layer 3. Thus, the semi-solidified molten droplet 4 will reflect upon impacting the deposition layer 3, with only a portion fusing to the deposition layer 3 and the rest reflecting out. If the reflected molten droplets 4 do not impact the deposition layer 3, it only results in material loss. However, most of the molten droplets 4, after reflection by the centrifugal disk 1, will impact the deposition layer 3 again. Since the molten droplets lose some kinetic energy and gradually solidify after multiple impacts, the subsequent impact on the deposition layer results in poor fusion between the droplet and the deposition layer, a loose structure affecting density, and the inability to form smaller dendrites. In summary, the key to solving this problem is to ensure that the molten droplet impacts the deposition layer radially and directly along the centrifugal disk, eliminating the possibility of droplet reflection at the source. Summary of the Invention

[0006] To overcome the shortcomings of the prior art, the present invention discloses a centrifugal disc that can radially eject molten metal droplets, the purpose of which is to enable the droplets to impact the deposition layer radially and head-on along the centrifugal disc, thereby eliminating the possibility of droplet reflection from the source.

[0007] To achieve the above-mentioned objectives, the present invention adopts the following technical solution:

[0008] A centrifuge disc capable of radially ejecting molten metal droplets has multiple ejection channels evenly distributed circumferentially on its surface. The center line of each channel is a logarithmic spiral centered on the disc's center. A molten metal pool is located at the center of the disc. During operation, the centrifuge disc rotates in the opposite direction to the outward extension of the logarithmic spiral. Molten metal from the pool enters each ejection channel and is ejected radially from the end of each channel.

[0009] The following beneficial effects can be achieved by implementing the above technical solution:

[0010] 1. The centrifugal trough with a logarithmic spiral centerline allows molten droplets to be ejected radially from the centrifugal disc and impact the deposition layer. Because it is a radial head-on impact, the molten droplets fuse directly with the deposition layer after impact. A small amount of sputtering may occur, but no reflection will occur. This solves the problem of reflected molten droplets impacting the deposition layer again from the source.

[0011] 2. This radial frontal impact not only helps to improve the density of the fusion between the molten droplet and the deposited layer and form a fine grain structure, but also allows the molten droplet to be almost completely fused to the deposited layer, which greatly improves the effective deposition rate of the metal material.

[0012] 3. During operation, the molten droplets move in a logarithmic spiral within the centrifugal disc. Since the logarithmic spiral is independent of the rotational speed, the molten droplets are always ejected radially from the centrifugal disc, regardless of the speed of the centrifugal disc.

[0013] The technical solution is further improved, and the expression for the logarithmic spiral is:

[0014] r = R * e θ ;

[0015] In the formula, r is the polar radius, R is the radius of the molten pool, θ is the polar angle, and θ > π.

[0016] The beneficial effects of implementing the above technical solution are: the polar angle θ > π, which can increase the stiffness of the logarithmic spiral, and the centrifugal acceleration of the molten droplet will increase exponentially with the polar angle θ.

[0017] To further improve the technical solution, an outlet hole is provided between the molten metal pool and the slinging tank. During operation, the molten metal in the molten metal pool enters each slinging tank through the outlet hole.

[0018] The beneficial effects of implementing the above technical solution are: the set liquid outlet hole is equivalent to a flow limiting hole, which can prevent too much molten metal from entering the liquid throwing tank and forming droplets with excessive diameter.

[0019] To further improve the technical solution, a downward-sloping conical surface is provided at the edge of the centrifuge disc. When working, the molten droplets impact the deposition layer and are reflected. The reflected molten droplets are then reflected downwards by the conical surface after impacting it.

[0020] The beneficial effects of implementing the above technical solution are as follows: the impact motion is very complex, and a small number of molten droplets may be reflected after impacting the deposition layer, and then impact the deposition layer again through reflection by the centrifugal disk. By setting the conical surface, the molten droplets can be reflected downwards, preventing them from impacting the deposition layer.

[0021] To further improve the technical solution, a hot-melt material is wrapped around the edge of the centrifugal disc. When working, the molten droplets impact the deposition layer and are reflected. The reflected droplets are then absorbed by the hot-melt material after impacting it.

[0022] The beneficial effects of implementing the above technical solution are as follows: Since molten metal droplets are highly heated liquid droplets, when they impact the molten material, they can instantly soften the material. At this point, the droplet will embed itself or penetrate into the molten material, eliminating the possibility of reflection. This fundamentally solves the problem of reflected droplets re-impacting the deposition layer.

[0023] To further improve the technical solution, the hot melt material is any one of asphalt, plastic, or hot melt adhesive.

[0024] The beneficial effects of implementing the above technical solution are: asphalt, plastics, hot melt adhesives, etc. are all common hot melt materials that can be wrapped around the edge of the centrifugal disc. Attached Figure Description

[0025] Figure 1 The diagram shown is a schematic of the structure of an existing centrifuge disc.

[0026] Figure 2 The diagram shows a schematic of an existing centrifuge disc with radial grooves.

[0027] Figure 3 What is shown is Figure 2 Top view.

[0028] Figure 4 The diagram shown is a three-dimensional structural schematic of this centrifuge disc.

[0029] Figure 5 The diagram shown is a motion analysis diagram of the ball within the radial groove.

[0030] Figure 6 The diagram shows the trajectory of the ball within the logarithmic spiral groove at time T1.

[0031] Figure 7 The diagram shows the trajectory of the ball within the logarithmic spiral groove at time T21.

[0032] Figure 8 The diagram shown is a motion analysis diagram of a small ball within a logarithmic spiral groove.

[0033] Figure 9-11 The diagram shown is a schematic of an improved version of this centrifuge disc.

[0034] In the picture:

[0035] 1. Centrifuge tray;

[0036] 11. Molten pool; 12. Splashing tank; 13. Outlet hole; 14. Conical surface; 15. Hot melt material; 16. Radial groove;

[0037] 2. Metal substrate;

[0038] 3. Sedimentary layer;

[0039] 4. Molten droplets;

[0040] 5. Small ball. Detailed Implementation

[0041] Preferred embodiments of the present invention will now be described with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection 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," and "outer," indicating directions or positional relationships, are based on the directions or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or element must have a specific orientation, or be constructed and operated in a specific orientation; therefore, it should not be construed as a limitation of the present invention. It should also be noted that in the description of the present invention, unless otherwise explicitly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium, or a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in the present invention according to the specific circumstances.

[0042] like Figure 4 As shown, a centrifuge disc capable of radially ejecting molten metal droplets has ten ejection channels 12 evenly distributed circumferentially on its surface. The center line of each channel 12 is a logarithmic spiral centered on the center of the disc surface. A molten pool 11 is located at the center of the disc surface and is connected to the ten ejection channels 12.

[0043] If we want to study the motion of the molten droplet 4 in the liquid-throwing tank 12, we must first study the motion trajectory of the ball 5 in the radial groove 16.

[0044] Reference Figure 5 When the centrifugal disc 1 rotates counterclockwise, the small ball 5 is subjected to two forces within the radial groove 16: one is the pushing force Ft exerted by the radial groove 16 on the small ball 5, and the other is the centrifugal force Fr. The resultant force of the pushing force Ft and the centrifugal force Fr is F, and the direction of the resultant force F is inclined, with an angle α between it and the radial line.

[0045] Similarly, ball 5 generates two velocities: a circumferential velocity Vt, the direction of which is the same as the thrust Ft, and the magnitude of which depends on the rotational speed of the centrifugal disk 1 and the position of ball 5; and a 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. The resultant velocity of Vt and Vr is V, and the direction of the resultant velocity V is also inclined, with an angle α between it and the radial line. This indicates that ball 5 will be thrown out of the radial groove 16 in an inclined direction.

[0046] If observed from within the centrifugal disk 1, the ball 5 undergoes only linear motion with variable acceleration within the radial groove 16, where acceleration increases with radius. However, if observed from outside the centrifugal disk 1, the ball 5 not only undergoes linear motion with variable acceleration within the radial groove 16 but also circular motion with increasing rotational speed in the circumferential direction. Thus, the trajectory of the ball 5 on the centrifugal disk 1 is a logarithmic spiral centered on the disk's center.

[0047] According to the properties of a logarithmic spiral, the angle between the tangent at any point on the spiral and the radial line is equal. Therefore, the angle α between the resultant force F and the radial line remains unchanged, and the angle α between the resultant velocity V and the radial line also remains unchanged. The formula for a logarithmic spiral is r = R*e. θ When θ > π, Vr ≈ Vt, Ft ≈ Fr. In this case, α is approximately 45°. Furthermore, a polar angle θ > π increases the stiffness of the logarithmic spiral, and the centrifugal acceleration of ball 5 increases exponentially with the polar angle θ.

[0048] So, let's change our perspective and change the reference target. If we create a liquid-spraying trough 12 with a logarithmic spiral centerline on the centrifuge disc 1, and place a small ball 5 with an initial velocity of zero inside the liquid-spraying trough 12, and then rotate the centrifuge disc 1 clockwise, then when observed from outside the centrifuge disc 1, the trajectory of the small ball 5 in the liquid-spraying trough 12 will be a logarithmic spiral.

[0049] Reference Figure 6 At time T1, standing outside the centrifuge plate 1, it can be observed that ball 5 is located at point P1 in the logarithmic spiral groove. At this time, ball 5 is also located in the virtual radial groove 16.

[0050] Reference Figure 7 At time T2, if observed from outside the centrifugal disk 1, the ball 5 can be seen moving to point P2 in the logarithmic spiral groove. At this time, the ball 5 is still located in the virtual radial groove 16.

[0051] Therefore, viewed from outside the centrifugal disk 1, the ball 5 is essentially moving within a non-rotating radial groove 16, undergoing variable acceleration linear motion with its radius continuously increasing. The angle of the radial groove 16 is related to the initial position of the ball 5. This indicates that the ball 5 will be thrown out radially from the centrifugal disk 1.

[0052] Reference Figure 8 Because the rotation of centrifugal disk 1 has reversed, the directions of Vt and thrust Ft have also reversed. At this time, the resultant velocity of Vt and V is Vr, and the resultant force of Ft and F is Fr. Compared with the motion of ball 5 in radial groove 16, the ejection velocity of ball 5 will be reduced.

[0053] In this invention, the molten droplet 4 is equivalent to a small ball 5. Observed from outside the centrifuge disk 1, the trajectory of the molten droplet 4 in the sling bath 12 is a straight line, and this straight line is the radial line of the centrifuge disk 1. The molten droplet 4 can be ejected radially along the centrifuge disk 1, impacting the deposition layer 3 in a forward direction. Because it is a forward impact, the molten droplet 4 directly fuses with the deposition layer 3 after impacting it. A small amount of sputtering may occur, but no reflection will occur. This solves the problem of the reflected molten droplet 4 impacting the deposition layer 3 again from the source. Compared with oblique impact, this radial forward impact not only helps to improve the density of the fusion between the molten droplet 4 and the deposition layer 3 and form a fine grain structure, but also allows the molten droplet 4 to almost completely fuse with the deposition layer 3, greatly improving the effective deposition rate of the metallic material.

[0054] Furthermore, the movement of the molten droplet 4 within the centrifugal casting tank 12 is independent of the rotational speed. In other words, regardless of the rotational speed of the centrifugal disc 1, the molten droplet 4 can always be ejected radially from the centrifugal disc 1.

[0055] Reference Figure 9 In one of the improved technical solutions, the molten pool 11 is a cylindrical body with multiple outlet holes 13 on its wall. During operation, the molten metal in the molten pool 11 enters each casting tank 12 through the outlet holes 13. The outlet holes 13 are equivalent to flow restrictors, preventing excessive molten metal from entering the casting tank 12 and forming excessively large droplets 4.

[0056] Reference Figure 10 In another improved technical solution, a downwardly inclined conical surface 14 is provided at the edge of the centrifugal disk 1. When working, the molten droplet 4 impacts the deposition layer 3 and is reflected. The reflected molten droplet 4 is then reflected downward by the conical surface 14 after impacting the conical surface 14.

[0057] The impact process is complex. A small number of molten droplets 4 may be reflected after impacting the deposition layer 3, and then impact the deposition layer 3 again through reflection from the centrifuge disk 1. With the conical surface 14, the molten droplets 4 can be reflected downwards and fall to the bottom of the tank, no longer impacting the deposition layer 3. The molten droplets 4 that fall to the bottom of the tank can be reused after cooling.

[0058] Reference Figure 11 Additionally, a hot melt material 15 can be wrapped around the edge of the centrifuge disc 1. During operation, the molten droplets 4 impact the deposition layer 3 and are reflected. The reflected droplets 4 are then absorbed by the hot melt material 15 after impacting it. The hot melt material 15 can be any of asphalt, plastic, or hot melt adhesive. Asphalt, plastic, and hot melt adhesive are all common hot melt materials 15 that can be wrapped around the edge of the centrifuge disc 1.

[0059] The molten metal droplet 4 is a highly heated droplet. When the droplet 4 impacts the molten material 15, it can instantly soften the molten material 15. At this time, the droplet 4 will be embedded or penetrate into the molten material 15, losing the possibility of reflection. This fundamentally solves the problem of the reflected droplet 4 impacting the deposition layer 3 again.

[0060] The hot melt material needs to be replaced periodically, and the replaced hot melt material contains solidified metal. To recover the metal, the hot melt material can be removed by hot melting, and the metal can be filtered out.

[0061] The parts not detailed herein are prior art. Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A centrifugal disc capable of radially ejecting molten metal droplets, characterized in that: in Multiple spools are evenly distributed circumferentially on the surface of the centrifuge disc. The center line of each spool is a logarithmic spiral centered on the center of the disc surface. The expression for the logarithmic spiral is: In the formula, r is the polar radius, R is the radius of the molten pool, θ is the polar angle, and θ > π. A molten metal pool is located at the center of the disc. During operation, the centrifugal disc rotates in the opposite direction to the outward extension of the logarithmic spiral. The molten metal in the molten metal pool enters each slinging tank and is slinged out radially from the end of each slinging tank along the centrifugal disc. The edge of the centrifugal disc is wrapped with a hot melt material. When working, the molten droplets impact the deposition layer and are reflected. The reflected droplets are then absorbed by the hot melt material after impacting it.

2. The centrifugal disc for radially ejecting molten metal droplets as described in claim 1, characterized in that: A liquid outlet is provided between the molten metal pool and the liquid ejection tank. During operation, the molten metal in the molten metal pool enters each liquid ejection tank through the liquid outlet.

3. A centrifugal disc capable of radially ejecting molten metal droplets as described in claim 1, characterized in that: in The edge of the centrifuge disc has a downward-sloping conical surface. When working, the molten droplets hit the deposition layer and are reflected. The reflected droplets hit the conical surface and are then reflected downwards by the conical surface.

4. A centrifugal disc capable of radially ejecting molten metal droplets as described in claim 1, characterized in that: The hot melt material is any one of asphalt, plastic, or hot melt adhesive.

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