Foam metal production system based on hollow microsphere continuous feeding
Through the foam metal production system of continuous feed of hollow microbeads, the continuous transport and upflow of hollow microbeads is achieved by using the screw push mechanism and the floating channel, which solves the problem of difficult to control the bubble size and improves the performance and production efficiency of foam metal.
Patent Information
- Application Number
- CN202510745266.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-06-05
- Publication Date
- 2025-08-01
AI Technical Summary
The existing blowing method is difficult to control the bubble size when preparing foam aluminum, and the bubble sizes are different and the pore sizes are uneven, which affects production efficiency and product quality.
A foam metal production system using a continuous feed of hollow microbeads is used to set up a screw push mechanism and upward channel in the melt pool, and the continuous transport and upward of hollow microbeads is achieved by using push screws and driving devices to produce foam metal instead of traditional bubbles.
Effectively control bubble size, improve the performance and production efficiency of foam metal, and ensure uniform pore size distribution.
Smart Images
Figure CN120394822A_ABST
Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of porous foam materials, and in particular relates to a foam metal production system based on continuous feeding of hollow microspheres. Background Art
[0002] Aluminum foam is made by adding additives to pure aluminum or aluminum alloys and then foaming them. It combines the characteristics of both metal and bubbles. It boasts low density, high impact absorption, high temperature resistance, strong fire resistance, corrosion resistance, sound insulation and noise reduction, low thermal conductivity, high electromagnetic shielding, strong weather resistance, filtering capabilities, ease of processing and installation, high forming precision, and surface coating. It has enormous market potential in railway passenger vehicles, military, construction, automotive, decoration, aerospace, aviation, and shipbuilding. Aluminum foam can be categorized into open-cell and closed-cell based on its pore structure, with closed-cell aluminum foam being more widely used. Closed-cell aluminum foam is primarily produced by melt blowing.
[0003] In the melt blowing process, gas is directly injected into liquid aluminum or aluminum alloy through a blowing head, which has the advantages of low cost and continuous production. However, in the existing blowing method, all bubbles are generated in one or more groups of pores machined on the plane, and the gas output is uneven and uncontrollable, resulting in different bubble sizes, difficult to accurately control the pore size, and uneven pore size distribution in the final product. The biggest problem with the existing planar pores of the blowing method is the slow bubble detachment speed, which greatly affects the production efficiency and bubble pore size control. In order to control the bubble pore size and improve production efficiency, the rotary blowing method and the reciprocating blowing method are proposed. The rotary blowing method drives the blowing head to rotate to achieve gas dispersion, and the reciprocating blowing method disperses the bubbles by driving the blowing head to perform reciprocating motion. However, the rotary blowing method and the reciprocating blowing method cause greater disturbance to the melt, and the bubble detachment conditions vary greatly, and the uniformity of the prepared foam aluminum pores is poor. In particular, the interference caused by vibration causes a large number of bubbles to merge, further exacerbating the unevenness of the bubbles and the difficulty of control. Hollow glass microspheres, a new material developed in recent years, are widely used and offer excellent performance. Hollow glass microspheres are tiny, hollow, spherical powders. Particle size can be adjusted to any micron level, depending on the application. With a density of 0.1-0.7 g / ml, hollow glass microspheres offer advantages such as light weight, high volume, low thermal conductivity, high compressive strength, and excellent dispersibility, flowability, and stability. Furthermore, hollow glass microspheres exhibit excellent properties such as insulation, self-lubrication, sound insulation, non-absorption, fire resistance, corrosion resistance, radiation protection, and non-toxicity. Summary of the Invention
[0004] In view of the excellent properties of hollow microspheres, replacing traditional bubbles with hollow microspheres can solve the problem of difficult control of bubble size and effectively improve the performance of foamed metals. In view of this, the purpose of the present invention is to provide a foamed metal production system based on continuous feeding of hollow microspheres.
[0005] To achieve the above object, the present invention provides the following technical solutions: A foamed metal production system based on continuous feeding of hollow microspheres, comprising: A molten pool, the upper end of the molten pool is open and used for accommodating molten metal liquid; A discharge guiding device, arranged above the molten pool and used for guiding the formed foamed metal material to continuously discharge; A microsphere feeding device, used for continuously adding hollow microspheres to the molten pool; The discharge guiding device includes a first guiding part and a second guiding part arranged oppositely, and a discharge guiding channel for the forming and discharging of the foamed metal material is formed between the first guiding part and the second guiding part; a floating channel for guiding the hollow microspheres into the discharge guiding channel is arranged in the molten pool; The microsphere feeding device includes a screw pushing mechanism, the screw pushing mechanism includes a pushing channel, a pushing screw arranged in the pushing channel, and a driving device drivingly connected to the pushing screw; the first end port of the pushing channel is located below the floating channel and is set as a discharge port for conveying hollow microspheres into the floating channel, the second end of the pushing channel is provided with a feeding channel, and a feeding hopper is arranged on the feeding channel; The pushing channel is inclined, and the first end of the pushing channel is located below the second end; or, the pushing channel is inclined, and the first end of the pushing channel is located above the second end; or, the pushing channel is horizontally arranged.
[0006] Further, a flow control valve for controlling the continuous feeding flow rate of hollow microspheres is arranged on the feeding channel.
[0007] Further, the driving device adopts a servo motor, and the pushing screw includes a screw rotating shaft and a spiral pushing blade arranged on the screw rotating shaft; the output shaft of the servo motor is drivingly connected to the screw rotating shaft; The servo motor is located outside the molten pool, and the servo motor is drivingly connected to the screw rotating shaft through a transmission shaft, or, the pushing channel extends outside the molten pool, and the servo motor is drivingly connected to the screw rotating shaft through a transmission shaft or a coupling.
[0008] Further, the first end of the screw rotating shaft extends outside the pushing channel; a bearing seat for supporting the screw rotating shaft is installed in the molten pool.
[0009] Furthermore, a propeller blade assembly for evenly distributing the hollow microspheres is provided in the floating channel; the propeller blade assembly includes a propeller blade located in the floating channel and a first propeller blade driving assembly drivingly connected to the rotating shaft of the propeller blade.
[0010] Furthermore, the floating channel is arranged at one end of the molten liquid pool, and a driving propeller blade assembly for driving the molten metal to flow towards the floating channel is provided at the other end of the molten liquid pool opposite to the floating channel.
[0011] Furthermore, the driving propeller blade assembly includes a driving propeller blade and a second propeller blade driving assembly drivingly connected to the rotating shaft of the driving propeller blade.
[0012] Furthermore, the hollow microspheres are hollow ceramic microspheres, hollow glass microspheres or hollow spheres made of metal materials.
[0013] Furthermore, the pushing channel is inclined, and the inclination angle of the pushing channel is 15°-30°.
[0014] Furthermore, the pushing channel is made of titanium alloy material, high-temperature resistant metal ceramic material or graphite; the pushing screw is made of titanium alloy material or high-temperature resistant metal ceramic material.
[0015] The beneficial effects of the present invention are as follows: The foam metal production system based on continuous feeding of hollow microspheres of the present invention can meet the purpose of continuous transportation of hollow microspheres by arranging a screw pushing mechanism in the molten liquid pool. Specifically, by arranging the pushing channel inclined and arranging a pushing screw in the pushing channel, and driving the pushing screw to rotate by a driving device, the hollow microspheres transported from the feeding channel into the pushing channel can be transported to the discharge port at the first end of the pushing channel, and the buoyancy force of the hollow microspheres in the molten metal can be overcome by the pushing force of the pushing screw, so as to meet the purpose of continuous feeding of hollow microspheres; by arranging a floating channel between the discharge port and the discharge guiding channel, the hollow microspheres can be guided to continuously float into the discharge guiding channel to meet the production requirements of the foam metal material; in summary, the foam metal production system based on continuous feeding of hollow microspheres of the present invention can solve the problem of difficult control of the bubble size and effectively improve the performance of the foam metal by using hollow microspheres instead of traditional bubbles to produce foam metal. BRIEF DESCRIPTION OF THE DRAWINGS
[0016] In order to make the objectives, technical solutions and beneficial effects of the present invention clearer, the present invention provides the following drawings for illustration: Figure 1 It is a schematic structural diagram of the foam metal production system based on continuous feeding of hollow microspheres of the present invention, specifically the structural diagram when the first end of the pushing channel is below the second end; Figure 2 of Figure 1 Enlarged view of area A; Figure 3 Schematic structural diagram of the foam metal production system when the first end of the pushing channel is above the second end; Figure 4 Schematic structural diagram of the foam metal production system when the pushing channel is horizontally arranged and entirely located in the molten metal pool; Figure 5 Schematic structural diagram of the foam metal production system when the pushing channel is horizontally arranged and the second end extends out of the molten metal pool.
[0017] Explanation of reference numerals: 1 - Hollow microspheres; 10 - Molten metal pool; 11 - Molten metal; 12 - Floating channel; 13 - Propeller blade; 14 - First drive motor; 15 - Bevel gear transmission mechanism; 16 - Driving blade; 17 - Second drive motor; 18 - Coupling; 21 - First guiding part; 22 - Second guiding part; 23 - Discharge guiding channel; 24 - First guiding roller; 25 - First guiding belt; 26 - Second guiding roller; 27 - Second guiding belt; 28 - Tool holder; 29 - Cutting tool; 31 - Pushing channel; 311 - Discharge port; 32 - Driving device; 33 - Screw rotating shaft; 34 - Screw pushing blade; 35 - Coupling; 36 - Feeding channel; 37 - Feeding hopper; 38 - Flow control valve; 39 - Bearing seat; 40 - Transmission shaft; 41 - Sealing structure. Detailed implementation manners
[0018] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments, so that those skilled in the art can better understand the present invention and be able to implement it, but the embodiments given are not intended to limit the present invention.
[0019] As Figure 1 shown, the foam metal production system based on continuous feeding of hollow microspheres in this embodiment includes a molten metal pool 10, a discharge guiding device, and a microsphere feeding device.
[0020] In this embodiment, the upper end of the molten metal pool 10 is open and is used to accommodate molten metal 11, and a floating channel 12 located below the discharge guiding device is provided in the molten metal pool 10.
[0021] In this embodiment, a discharge guide device is disposed above the molten pool 10 and is used to guide the continuous discharge of the formed foam metal material. In this embodiment, the discharge guide device includes a first guide portion 21 and a second guide portion 22 disposed opposite each other. A discharge guide channel 23 for forming and discharging the foam metal material is formed between the first guide portion 21 and the second guide portion 22. A floating channel 12 is provided below the discharge guide channel 23 to guide the hollow microspheres in their upward floating direction. The floating channel 12 is used to guide the hollow microspheres to float upward and enter the discharge guide channel 23.
[0022] In this embodiment, a first guide roller 24 and a second guide roller 26 are spaced apart on the opposing sides of the first guide section 21 and the second guide section 22, respectively. A first guide belt 25 is mounted on the first guide roller 24, and a second guide belt 27 is mounted on the second guide roller 26. The spacing between the first guide section 21 and the second guide section 22 is adjustable. Thus, the first guide roller 24 and the second guide roller 26 drive the first and second guide belts 25 and 27 to move upward synchronously, driving the foam metal material upward along the discharge guide channel 23 and continuously discharging the material. In this embodiment, the first and second guide sections 21 and 22 are equipped with water-cooling jackets (not shown) for cooling the foam metal material during forming. The water-cooling jackets control the cooling rate of the foam metal material to 10-50°C / s.
[0023] In this embodiment, a cutting device for cutting the foam metal material is provided on the discharge guiding device. The cutting device is vertically above the discharge guiding device. The cutting device can be provided at the outlet of the discharge guiding channel 23. After the foam metal material comes out of the outlet of the discharge device, the cutting device can cut the foam metal material. In some embodiments, the cutting device includes a knife holder 28 and a cutter 29. The knife holder 28 is installed on the top surface of the first guide part 21. When the cutter 29 is working, it moves in the horizontal direction relative to the first guide part 21 to cut the foam metal material. In addition, during the process of the cutter 29 cutting the foam metal material, the driving mechanism provided in the knife holder 28 also drives the cutter 29 to move synchronously with the foam metal material to make the incision smoother, and the cutter 29 will not affect the continuous discharge of the foam metal material.
[0024] The microbead feeding device of this embodiment includes a screw pushing mechanism, which includes a pushing channel 31, a pushing screw arranged in the pushing channel 31, and a driving device 32 connected to the pushing screw; the first end port of the pushing channel 31 is located below the floating channel 12 and is provided as a discharge port 311 for conveying hollow microbeads into the floating channel 12, and the second end of the pushing channel 31 is provided with a feeding channel 36, and the feeding channel 36 is provided with a feeding hopper 37.
[0025] In this embodiment, the driving device 32 adopts a servo motor. The pushing screw includes a screw rotating shaft 33 and a spiral pushing blade 34 arranged on the screw rotating shaft 33; the output shaft of the servo motor is in transmission connection with the screw rotating shaft 33.
[0026] In this embodiment, the pushing channel 31 is inclined, and the first end of the pushing channel 31 is located below the second end. Specifically, the first end of the pushing channel 31 is located below the floating channel 12, and the second end extends out of the molten pool 10. The feeding channel 36 and the feeding hopper 37 are both arranged on the second end of the pushing channel 31 that extends out of the molten pool 10. Specifically, in this embodiment, the output shaft of the servo motor is connected to the screw rotating shaft 33 through a coupling 35, and at this time, the servo motor and the screw rotating shaft 33 are coaxially inclined. Of course, in some other embodiments, the servo motor can be horizontally installed, and the output shaft of the servo motor is connected to the screw rotating shaft 33 through a universal joint, which will not be elaborated here.
[0027] As Figure 3 shown, in some other embodiments, the pushing channel 31 is inclined, and the first end of the pushing channel 31 is located above the second end. At this time, the whole pushing channel 31 can be arranged in the molten pool 10, and a sealing structure is provided between the pushing channel 31 and the screw rotating shaft 33 to prevent the metal such as from entering from the second end of the pushing channel 31. The output shaft of the servo motor is in transmission connection with the screw rotating shaft 33 through a transmission shaft 40, and the transmission shaft 40 and the screw rotating shaft 33 can adopt a bevel gear transmission mechanism and a face gear transmission mechanism to realize the transmission connection. At this time, the feeding hopper 37 is arranged above the molten pool 10, and the feeding channel 36 connects the feeding hopper 37 and the pushing channel 31.
[0028] As Figures 4 - 5 shown, in some other embodiments, the pushing channel 31 is horizontally arranged. As Figure 4 shown, at this time, the whole pushing channel 31 can be arranged in the molten pool 10, and a sealing structure 41 is provided between the pushing channel 31 and the screw rotating shaft 33 to prevent the metal such as from entering from the second end of the pushing channel 31. The output shaft of the servo motor is in transmission connection with the screw rotating shaft 33 through a transmission shaft 40, and the transmission shaft 40 and the screw rotating shaft 33 can adopt a bevel gear transmission mechanism and a face gear transmission mechanism to realize the transmission connection. At this time, the feeding hopper 37 is arranged above the molten pool 10, and the feeding channel 36 connects the feeding hopper 37 and the pushing channel 31. As Figure 5 shown, at this time, the second end of the pushing channel 31 can be extended out of the molten pool 10, and the output shaft of the servo motor is connected to the screw rotating shaft 33 through a coupling 35. At this time, the feeding channel 36 and the feeding hopper 37 are both arranged on the second end of the pushing channel 31 that extends out of the molten pool 10.
[0029] In addition, since the sizes of the hollow microspheres 1 are mostly in the micron range, after the pushing channel 31 is filled with the hollow microspheres 1, due to the relatively high viscosity and surface tension of the molten metal itself, and the poor affinity between the material of the hollow microspheres 1 and the molten metal, under natural conditions, due to the blocking effect of the hollow microspheres 1, the distance that the molten metal penetrates into the pushing channel 31 is short, that is, it can be considered that the molten metal cannot penetrate into the pushing channel 31, let alone enter the feeding channel 36. That is, there is no molten metal in the feeding channel 36, and the hollow microspheres 1 can directly fall into the pushing channel 31 under the action of gravity. In particular, before use, the pushing channel 31 should be filled with the hollow microspheres 1 first, and then the molten metal should be injected into the melting pool 10, which will not be elaborated here.
[0030] In a preferred embodiment of the present embodiment, a flow control valve 38 for controlling the continuous feeding flow rate of the hollow microspheres 1 is provided on the feeding channel 36.
[0031] In a preferred embodiment of the present embodiment, the first end of the screw rotating shaft 33 extends beyond the pushing channel 31. A bearing seat 39 for supporting the screw rotating shaft 33 is installed in the melting pool 10 to improve the running stability of the screw rotating shaft 33. Of course, the bearing seat 39 is made of high-temperature resistant materials such as titanium alloy materials and high-temperature resistant metal ceramic materials, which will not be elaborated here.
[0032] In this embodiment, the pushing channel 31 is inclined, and the inclination angle of the pushing channel 31 is 15°-30°. If the inclination angle of the pushing channel 31 is too small, the size of the melting pool 10 will be increased. If the inclination angle of the pushing channel 31 is too large, the hollow microspheres will be difficult to be pushed to the discharge port 311 due to the buoyancy effect. Therefore, setting the inclination angle of the pushing channel 31 to 15°-30° can not only set the size of the melting pool 10 to an appropriate size, but also meet the continuous feeding requirements of the hollow microspheres 1.
[0033] In a preferred embodiment of the present embodiment, a propeller blade assembly for evenly distributing the hollow microspheres 1 is provided in the floating channel 12. Specifically, the propeller blade assembly includes a propeller blade 13 located in the floating channel 12 and a first blade drive assembly drivingly connected to the rotating shaft of the propeller blade 13. In this embodiment, the first blade drive assembly includes a first drive motor 14 installed on the side wall of the melting pool 10, and the output shaft of the first drive motor 14 is perpendicular to the rotating shaft of the propeller blade 13 and is drivingly connected through a bevel gear transmission mechanism 15. By providing the propeller blade assembly, the rotating propeller blade 13 can disperse the floating hollow microspheres 1 around, making the distribution of the hollow microspheres 1 in the floating channel 12 more uniform.
[0034] In a preferred embodiment of the present embodiment, the floating channel 12 is provided at one end of the molten pool 10, and a driving paddle assembly for driving the molten metal to flow towards the floating channel 12 is provided at the other end of the molten pool 10 opposite to the floating channel 12. In this embodiment, the driving paddle assembly includes a driving paddle 16 and a second paddle driving assembly that is drivingly connected to the rotating shaft of the driving paddle 16. In this embodiment, the second paddle driving assembly includes a second driving motor 17 installed on the side wall of the molten pool 10, and the output shaft of the second driving motor 17 is drivingly connected to the rotating shaft of the driving paddle 16 through a coupling 18.
[0035] In this embodiment, the hollow microspheres can be hollow ceramic microspheres, hollow glass microspheres, hollow spheres made of metal materials, etc., which will not be elaborated here.
[0036] In this embodiment, all components located inside the molten pool 10 are made of high-temperature resistant materials, including high-temperature resistant cermet materials, titanium alloy materials, or graphite, etc. Specifically, the pushing channel 31 is made of titanium alloy materials, high-temperature resistant cermet materials, or graphite. In this embodiment, the pushing channel 31 is made of graphite. The pushing screw is made of titanium alloy materials or high-temperature resistant cermet materials. In this embodiment, the pushing screw is made of titanium alloy materials.
[0037] In this embodiment, the output shaft of the first driving motor 14 and the molten pool 10 adopt a high-temperature resistant sealing and matching method; similarly, the output shaft of the second driving motor 17 and the molten pool 10 adopt a high-temperature resistant sealing and matching method. The high-temperature resistant sealing method can be a mechanical labyrinth seal, which will not be elaborated here.
[0038] The foam metal production system based on continuous feeding of hollow microspheres in this embodiment can meet the purpose of continuous transportation of hollow microspheres by setting a screw pushing mechanism in the molten pool. Specifically, by obliquely arranging the pushing channel and setting a pushing screw in the pushing channel, and using the driving device to drive the pushing screw to rotate, the hollow microspheres transported from the feeding channel into the pushing channel can be transported to the discharge port at the first end of the pushing channel. By using the pushing force of the pushing screw to overcome the buoyancy of the hollow microspheres in the molten metal, the purpose of continuous feeding of hollow microspheres can be achieved; by setting a floating channel between the discharge port and the discharge guiding channel, the hollow microspheres can be guided to continuously float into the discharge guiding channel to meet the production requirements of the foam metal material; in summary, the foam metal production system based on continuous feeding of hollow microspheres in this embodiment can solve the problem of difficult control of bubble size and effectively improve the performance of the foam metal by using hollow microspheres instead of traditional bubbles to produce foam metal.
[0039] The above-described embodiments are merely preferred embodiments cited to fully illustrate the present invention, and the protection scope of the present invention is not limited thereto. Equivalent substitutions or transformations made by those skilled in the art on the basis of the present invention are within the protection scope of the present invention. The protection scope of the present invention shall be subject to the claims.
Claims
1. A foam metal production system based on continuous feeding of hollow microspheres, characterized in that: Comprising: A molten liquid pool, the upper end of the molten liquid pool being open and used for containing molten metal liquid; A discharge guiding device, arranged above the molten liquid pool and used for guiding the continuous discharge of the formed foam metal material; A microsphere feeding device, used for continuously feeding hollow microspheres into the molten liquid pool; The discharge guiding device includes a first guiding part and a second guiding part arranged oppositely, and a discharge guiding channel for the forming and discharging of the foam metal material is formed between the first guiding part and the second guiding part; a floating channel for guiding the hollow microspheres into the discharge guiding channel is arranged in the molten liquid pool; The microsphere feeding device includes a screw pushing mechanism, the screw pushing mechanism includes a pushing channel, a pushing screw arranged in the pushing channel, and a driving device in transmission connection with the pushing screw; the port of the first end of the pushing channel is located below the floating channel and is set as a discharge port for conveying the hollow microspheres into the floating channel, a feeding channel is arranged at the second end of the pushing channel, and a feeding hopper is arranged on the feeding channel; The pushing channel is arranged obliquely, the first end of the pushing channel is located below the second end; or, the pushing channel is arranged obliquely, the first end of the pushing channel is located above the second end; or, the pushing channel is arranged horizontally.
2. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: A flow control valve for controlling the continuous feeding flow rate of the hollow microspheres is arranged on the feeding channel.
3. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: The driving device adopts a servo motor, the pushing screw includes a screw rotating shaft and a spiral pushing blade arranged on the screw rotating shaft; the output shaft of the servo motor is in transmission connection with the screw rotating shaft; The servo motor is located outside the molten liquid pool, the servo motor is in transmission connection with the screw rotating shaft through a transmission shaft, or, the pushing channel extends outside the molten liquid pool, and the servo motor is in transmission connection with the screw rotating shaft through a transmission shaft or a coupling.
4. The foam metal production system based on continuous feeding of hollow microspheres according to claim 3, wherein: The first end of the screw rotating shaft extends outside the pushing channel; a bearing seat for supporting the screw rotating shaft is installed in the molten liquid pool.
5. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: A propeller blade assembly for uniformly distributing the hollow microspheres is arranged in the floating channel; the propeller blade assembly includes a propeller blade located in the floating channel and a first blade driving assembly in transmission connection with the rotating shaft of the propeller blade.
6. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, wherein: The floating channel is arranged at one end of the molten liquid pool, and a driving propeller blade assembly for driving the metal liquid to flow towards the floating channel is arranged at the other end of the molten liquid pool opposite to the floating channel.
7. The foam metal production system based on continuous feeding of hollow microspheres according to claim 6, wherein: The driving propeller blade assembly includes a driving propeller blade and a second blade driving assembly in transmission connection with the rotating shaft of the driving propeller blade.
8. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: The hollow microspheres adopt hollow ceramic microspheres, hollow glass microspheres or hollow spheres made of metal materials.
9. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: The pushing channel is arranged obliquely, and the inclination angle of the pushing channel is 15° - 30°.
10. The foam metal production system based on continuous feeding of hollow microspheres according to claim 1, characterized in that: The pushing channel is made of titanium alloy material, high-temperature resistant metal ceramic material or graphite; the pushing screw is made of titanium alloy material or high-temperature resistant metal ceramic material.