CN218111681U

CN218111681U - Kneading block for double-screw extruder

Info

Publication number: CN218111681U
Application number: CN202221914443.8U
Authority: CN
Inventors: 李朝明
Original assignee: Shanghai Liyuan Environmental Technology Co ltd; Nanjing Lingfeng Intelligent Technology Co ltd
Current assignee: Shanghai Liyuan Environmental Technology Co ltd; Nanjing Lingfeng Intelligent Technology Co ltd
Priority date: 2022-07-25
Filing date: 2022-07-25
Publication date: 2022-12-23
Anticipated expiration: 2032-07-25

Abstract

The utility model relates to a mediate piece for twin-screw extruder, be equipped with the piece body of mediating of internal spline including the center. The material of the kneading block body is high-speed steel, and a metal nitriding layer, a self-fluxing alloy spray welding layer and a nickel-based tungsten carbide spray coating layer with the hardness gradually increasing are sequentially prepared on the outer surface of the kneading block body outwards. The utility model discloses a surface at pure high-speed steel kneading block piles up a plurality of layers of hardness through spray-welding and supersonic speed flame spraying method and is the metal level that the gradient increases, avoids the hardness of outer surface layer to differ too greatly with the hardness of body, effectively improves the bonding strength between each layer, makes it exert best work efficiency and guarantee life in high temperature working process.

Description

Kneading block for double-screw extruder

Technical Field

The utility model belongs to the technical field of screw extruder, especially, relate to a hold between fingers piece for double screw extruder.

Background

The screw extruder is a mechanical production device widely applied to industries such as plastic, food and feed processing, and the working principle of the screw extruder is that pressure and shearing force are generated through rotation of a screw, so that physical or chemical changes occur after materials are subjected to mixing, extruding, shearing and the like, and finally a finished product is extruded at the terminal of the device. With the rapid development of polymer industry, various novel filling, reinforcing, modifying and functional polymer materials are emerging continuously, and are widely applied to various high-strength reinforced plastics. In order to reduce the manufacturing cost of plastic products and to improve certain properties thereof, various reinforcing fillers, such as talc and calcium carbonate, are generally added to the plastic products. Due to the addition of the auxiliary agent, various corrosive media (such as chloride, bromine, sulfide and the like) can be generated under the action of various physical and chemical properties in the extrusion production process. The introduction of these additives during the plastic processing process can cause corrosion or wear of the screw, or both. In the production process, a screw of the extruder is in a severe high-pressure high-temperature environment and bears huge friction force and shearing force, and the abrasion condition of the surface of the screw is serious. The abrasion of the screw increases the distance between the screw and the machine barrel, and the compression and shearing of the screw to the material are influenced, so that the product quality is reduced. On the other hand, frequent replacement of the worn and failed screw not only increases the cost, but also delays the production plan, and reduces the production efficiency, so that the wear of the screw is reduced, the working life of the screw is prolonged, the maintenance cost of the equipment is greatly reduced, the quality of the product is ensured, and higher economic benefit is brought to enterprises.

At present, the conventional heat treatment has little significance for improving the service performance of the screw material, the whole heat treatment technology cannot fully utilize the material, and various defects exist. For example, hot-dip coating, the range of the selection of materials by carburizing is narrow, and the wear resistance of the prepared coating is not enough; the cost for integrally manufacturing the thread element by using the high-strength alloy material is high, and the thread element which has excellent performance and is suitable for producing glass fiber or carbon fiber modified plastics cannot be produced at home.

High Velocity Oxygen (HVOF) is a high temperature, high velocity combustion flame stream generated by combustion of a hydrocarbon fuel gas such as propane or propylene, or hydrogen and high pressure oxygen in a combustion chamber or in a special nozzle. The supersonic flame spraying has moderate heat input, high spraying speed, difficult crystallization of the coating and compact structure, and is the preferred technology for preparing the surface coating of the thread element. However, the coating has high hardness, which is generally more than 1200HV (HRc 70) and greatly different from the hardness (HRc 60-62) of the matrix of the screw element, and the service life of the screw element cannot be exerted to the maximum extent in the high-temperature working process.

Many researches for improving the wear resistance of mechanical parts at home and abroad exist, but the working environment of the screw of the extruder is special, the friction is not common between metal and metal, but between metal and high polymer, and soft abrasive materials such as crop products and the like, and the friction and the wear are often accompanied with the corrosion of various corrosive media under higher temperature and contact stress, the friction and the wear mechanism of the type are very complex, and the industry urgently needs to develop a special protection measure for enhancing the surface of the screw.

SUMMERY OF THE UTILITY MODEL

The utility model aims to solve the technical problem that a piece is mediated for double screw extruder is provided, improve the production efficiency and the life that are used for the double screw extruder of the especially fine and carbon fibre modified plastics of modified plastics when guaranteeing to mediate block shape and structural strength requirement.

The utility model provides a technical scheme that its technical problem adopted is: a kneading block for a twin-screw extruder is provided, which comprises a kneading block body provided with an internal spline at the center. The material of the kneading block body is high-speed steel, and a metal nitriding layer, a self-fluxing alloy spray welding layer and a nickel-based tungsten carbide spray coating layer with the hardness gradually increasing are sequentially prepared on the outer surface of the kneading block body outwards.

Further, all sharp edges of the kneading block body except the end faces are rounded and passivated, and the radius of the rounding is 0.2-0.5 mm.

Furthermore, the material of the kneading block body is W6Mo5Cr4V2 high-speed steel, and the surface hardness after heat treatment is HRC 60-62.

Further, the metal nitriding layer is prepared by spray welding on the outer surface of the kneading block body, the thickness of the metal nitriding layer is 0.2-0.3 mm, and the hardness of the metal nitriding layer is 750-850 HV.

Further, the self-fluxing alloy spray welding layer is prepared by spray welding on the outer surface of the metal nitriding layer, the thickness of the self-fluxing alloy spray welding layer is 1.0-1.5 mm, and the hardness of the self-fluxing alloy spray welding layer is 900-1000 HV.

Furthermore, the nickel-based tungsten carbide spray coating is prepared by a supersonic flame spraying method on the outer surface of the self-fluxing alloy spray welding layer, the thickness is 0.3-0.5 mm, and the hardness is more than 1200HV.

Advantageous effects

The utility model discloses a surface at pure high-speed steel kneading block piles up a plurality of layers of hardness through spray welding and supersonic speed flame spraying method and is the metal level that the gradient increases, avoids the hardness of outer surface layer to differ too greatly with the hardness of body, effectively improves the bonding strength between each layer, makes it exert best work efficiency and guarantee life in high temperature working process.

The utility model provides a piece is mediated to block has high tenacity and high rigidity concurrently, has excellent wearability, corrosion resistance and torsional strength, and its life is than the piece is mediated to pure W6Mo5Cr4V2 high-speed steel and improves more than 3 times, improves the production efficiency that is used for the especially fine and carbon fiber modified plastics's of modified plastics twin-screw extruder, has good price/performance ratio.

Drawings

FIG. 1 is a front view of a kneading block for a twin-screw extruder.

FIG. 2 is a half sectional view of a kneading block for a twin-screw extruder.

Wherein, 100-the kneading block body; 200-a metal nitriding layer; 300-self-fluxing alloy spray welding layer; 400-nickel base tungsten carbide spray coating. Like reference symbols in the various drawings indicate like elements.

Detailed Description

The present invention will be further described with reference to the following specific examples. It should be understood that these examples are only for illustrating the present invention and are not intended to limit the scope of the present invention. Furthermore, it should be understood that various changes and modifications of the present invention may be made by those skilled in the art after reading the teachings of the present invention, and these equivalents also fall within the scope of the appended claims.

As shown in figure 1, the utility model provides a mediate the piece center and be equipped with the internal spline, outwards its material be W6Mo5Cr4V2 high-speed steel, metal nitriding layer, from the fusible alloy spray welding layer, nickel base tungsten carbide spraying layer in proper order from the core.

As a preferred embodiment of the present invention, on the basis of the above technical solution, after the W6Mo5Cr4V2 high speed steel is processed to the shape of the kneading block body 100, the heat treatment hardness is HRc 60-62, and all sharp edges except the end surfaces are rounded and passivated, and the radius of the rounding is 0.5mm.

As a preferred embodiment of the present invention, on the basis of the above technical solution, the kneading block body 100 after the rounding treatment is nitrided, the thickness of the metal nitrided layer 200 is 0.2 to 0.3mm, and the hardness is 750 to 850HV.

As a preferred embodiment of the present invention, on the basis of the above technical solution, the surface of the nitrided kneading block is spray-welded with a layer of self-fluxing alloy, the thickness of the self-fluxing alloy spray-welding layer 300 is 1.0-1.5 mm, and the hardness of the spray-welding layer is 900-1000 HV. The adopted self-fluxing alloy comprises the following components in percentage by weight: c:0.7 to 1.1, B:3.0 to 4.0, si:3.5 to 5.0, cr:15 to 17, fe:2 to 5 percent, and the balance being Ni. The self-fluxing alloy spray welding layer 300 is metallurgically bonded with a matrix, has high density and excellent corrosion resistance and wear resistance.

As a preferred embodiment of the present invention, on the basis of the above technical solution, the surface of the kneading block is roughened by sandblasting, and then a supersonic flame spraying method is adopted. Directly spraying nickel-based tungsten carbide alloy powder on the surface of the kneading block by using a spray gun to obtain a nickel-based tungsten carbide coating, and repeatedly spraying the nickel-based tungsten carbide coating back and forth above the surface of the kneading block matrix by using the spray gun to stack the nickel-based tungsten carbide coatings layer by layer, wherein the thickness of each nickel-based tungsten carbide coating is 50-100 mu m, and the total thickness of the stacked nickel-based tungsten carbide spraying coating 400 is 0.3-0.5 mm; when the supersonic flame spraying is carried out, the flame flow speed of the supersonic flame spraying is more than 2000m/s, the speed of sprayed particles is 400-500m/s, the temperature of the outer surface of the kneading block is less than 100 ℃ when the supersonic flame spraying is carried out, the oxygen flow is 200-250L/min, the powder feeding rate is 25-35g/min, and the distance between a spray gun and the outer surface of the kneading block is 200-275mm when the supersonic flame spraying is carried out. The granularity of the nickel-based tungsten carbide alloy powder is 100-150 mu m, and the mass percentage content ratio of tungsten carbide to nickel is 40% -50% to 50% -60%.

The utility model discloses kneading the piece and having high tenacity and high rigidity concurrently, having excellent wearability, corrosion resistance and torsional strength, its life kneads the piece than pure W6Mo5Cr4V2 high-speed steel and improves more than 3 times, improves the production efficiency that is used for the double screw extruder of the especially fine and carbon fibre modified plastics of modified plastics, has good price/performance ratio.

Claims

1. The kneading block for the double-screw extruder comprises a kneading block body (100) with an internal spline in the center, and is characterized in that the kneading block body (100) is made of high-speed steel, and a metal nitriding layer (200), a self-fluxing alloy spray-welding layer (300) and a nickel-based tungsten carbide spray-coating layer (400) with gradually increased hardness are sequentially prepared on the outer surface of the kneading block body (100) outwards.

2. Kneading block for a twin-screw extruder according to claim 1, characterized in that all sharp edges of the kneading block body (100) except the end faces are rounded blunt, the radius of the rounding being 0.2-0.5 mm.

3. The kneading block for a twin-screw extruder according to claim 1, wherein the kneading block body (100) is made of W6Mo5Cr4V2 high speed steel and has a surface hardness of HRC60 to 62 after heat treatment.

4. Kneading block for a twin-screw extruder according to claim 1, characterized in that the metallic nitriding layer (200) is prepared by spray welding on the outer surface of the kneading block body (100), has a thickness of 0.2 to 0.3mm and a hardness of 750 to 850HV.

5. Kneading block for a twin-screw extruder according to claim 1, characterized in that the self-fluxing alloy spray-welded layer (300) is prepared by spray-welding on the outer surface of the metallic nitriding layer (200), has a thickness of 1.0 to 1.5mm and a hardness of 900 to 1000HV.

6. Kneading block for a twin-screw extruder according to claim 1, characterized in that the sprayed layer (400) of tungsten carbide nickel is produced by supersonic flame spraying on the outer surface of the sprayed layer (300) of self-fluxing alloy, with a thickness of 0.3-0.5 mm and a hardness of more than 1200HV.