A method and device for preparing cast tungsten carbide alloy

Abstract

The present invention provides a method and equipment for preparing a cast tungsten carbide alloy, including weighing raw materials according to the required proportions for casting tungsten carbide and pressing them into blocks; melting the block raw materials by electromagnetic induction under a protective atmosphere; pouring and casting them into a forming mold; after the casting is cooled, demolding to obtain a cast tungsten carbide alloy block; crushing and screening by a crusher to select the cast tungsten carbide powder that meets the requirements. The entire smelting process is surrounded by a protective atmosphere, so that the smelting process can be closed throughout the process, effectively preventing the molten metal from being contaminated by dust in the air. At the same time, in the electromagnetic suspension smelting process, the melt overcomes gravity and suspends in the smelting crucible, and is out of contact with the inner wall of the crucible, thereby obtaining high-temperature heating and effectively preventing the molten metal from being contaminated by the smelting crucible. It has the characteristics of improving the quality of the cast tungsten carbide powder products produced, making the product quality controllable and having better physical properties.

Description

Technical Field

[0001] The invention relates to the technical field of preparation of cast tungsten carbide alloy blocks, and in particular to a method and equipment for preparing cast tungsten carbide alloys. Background Art

[0002] Cast tungsten carbide powder is widely used in the reinforcement of metal surfaces of parts with high requirements for wear resistance and high temperature resistance in petroleum, geology, engineering machinery, etc. due to its high melting point (2535℃), high hardness and excellent wear resistance, so as to effectively improve work efficiency and service life. Traditional casting tungsten carbide powder is made by mixing tungsten carbide powder and tungsten powder in a tilting melting furnace, melting it in an open furnace cavity, cooling it in a graphite casting mold into a rod-shaped alloy block (WC, W2C eutectic), and then making it into powder through mechanical methods such as crushers and vibrating screens.

[0003] When casting tungsten carbide powder is prepared in this way, the working environment is exposed to the air, and there is floating dust in the air, which is integrated into the molten metal during the smelting process. In the smelting crucible, the molten metal will also contact the crucible wall. The residue in the smelting process is easy to accumulate on the crucible wall and finally mix with the molten metal, making the hardness of the product far different from the theoretical value of WC and W2C. The quality controllability of the product is poor, which will affect the performance of the product. Summary of the invention

[0004] In view of the above problems in the prior art, the present invention provides a method and equipment for preparing cast tungsten carbide alloy.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is as follows:

[0006] In a first aspect, a method for preparing a cast tungsten carbide alloy is provided, comprising:

[0007] S01. According to the required ratio for casting tungsten carbide, weigh W powder and WC powder and mix them as raw materials, and press the raw materials into blocks;

[0008] S02, feeding the bulk raw materials into a melting crucible of an electromagnetic suspension melting device under a protective atmosphere, and melting the bulk raw materials by utilizing the high temperature generated by electromagnetic induction;

[0009] S03, wait for the raw materials to be completely melted and evenly poured into a forming mold;

[0010] S04, after the casting is cooled, the forming mold is taken out from the smelting equipment, and demolding is performed to obtain a cast tungsten carbide alloy block;

[0011] S05. After the cast tungsten carbide alloy blocks are collected, they are crushed by a crusher and sieved to select the cast tungsten carbide powder that meets the requirements.

[0012] Furthermore, in step S01, the mass proportion of C in the raw material is 3.7-3.8%.

[0013] Furthermore, in step S02, the protective atmosphere is nitrogen.

[0014] Furthermore, in step S02, the electromagnetic suspension smelting equipment uses electromagnetic induction to control the heating temperature of the raw materials to 2500-3000°C.

[0015] Furthermore, in step S03, the staff observes the melting conditions of the raw materials in the crucible to ensure that the raw materials are completely and evenly melted.

[0016] In a second aspect, a device for preparing a cast tungsten carbide alloy is provided, which is applied to a method for preparing a cast tungsten carbide alloy proposed in the first aspect of the present application, comprising a furnace body, a smelting crucible and a forming mold, wherein a smelting chamber and a mold chamber are provided in the furnace body, the smelting crucible is rotatably arranged in the smelting chamber of the furnace body, a smelting induction coil is wound around the outer wall of the smelting crucible, and a mold frame for placing the forming mold is provided in the smelting chamber on one side of the smelting crucible.

[0017] The top of the furnace body is located directly above the melting crucible and is provided with a feeding barrel for feeding materials. The top of the furnace body is provided with a first observation hole for observing the melting situation in the melting crucible. The mold chamber is located on one side of the melting chamber. A first valve is provided in the furnace body at the connection between the melting chamber and the mold chamber. A mold transfer system for transferring the forming mold between the mold chamber and the mold frame is provided in the furnace body. A furnace door for opening and closing the mold chamber is provided on the furnace body.

[0018] Furthermore, the mold shifting system includes a first horizontal push rod, a second horizontal push rod and a lifting push rod. The first horizontal push rod and the second horizontal push rod are respectively arranged on the side walls of the smelting chamber and the mold chamber along the arrangement direction of the mold frame and the mold chamber. The push rods of the first horizontal push rod and the second horizontal push rod are coaxial and opposite to each other, and can clamp the forming mold placed on the mold frame. The lifting push rod is arranged on the bottom wall of the mold chamber.

[0019] Furthermore, it also includes a cooling system, which includes a cooling water flow channel. The furnace wall of the furnace body is set as a double-layer structure, and the cooling water flow channel is set in the interlayer of the furnace wall of the furnace body. The furnace body is cooled by cooling water passing through the cooling water flow channel.

[0020] Furthermore, a second observation hole is provided on the side wall of the furnace body close to the mold frame, through which the pouring of raw materials in the smelting crucible can be observed.

[0021] Furthermore, a feeding chamber is arranged above the furnace body, the bottom of which is connected to the discharge barrel, a second valve for opening and closing the discharge barrel is arranged below the feeding chamber, the top of the feeding chamber is open, and a top cover for opening and closing the feeding chamber opening is rotatably arranged.

[0022] The beneficial effects of the present invention are:

[0023] 1. The stable casting tungsten carbide powder product produced by the device and method provided in this application has a high feather structure and an irregular shape. The feather structure of the product is 90-95%, and the microhardness is greater than 2300kg / mm 2 The product has excellent comprehensive application performance; other properties such as wear resistance and impact toughness are also excellent.

[0024] 2. The product is smelted by electromagnetic induction heating, and the temperature can be controlled at 2500-2800℃, which gets rid of the higher temperature requirements (3000℃ and above) of traditional smelting process, and effectively reduces the consumption of various graphite materials.

[0025] 3. Compared with the common production method of cast tungsten carbide alloy blocks, the new process method and route eliminates the labor-intensive operation mode of the smelting process. The new method can realize the process automation control of multiple processes, improve the working environment, reduce the labor load of operators, and reduce labor costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic cross-sectional structure diagram of a furnace body, a forming mold, etc. of an apparatus for preparing cast tungsten carbide alloy according to Example 1 of the present application.

[0027] Figure 2 This is a schematic diagram of the raw material feeding process of the first furnace in Example 1 of the present application.

[0028] Figure 3 This is a schematic diagram of the raw material smelting process of the first furnace of Example 1 of the present application.

[0029] Figure 4 This is a schematic diagram of the process of pouring raw materials from the first furnace into the forming mold and the process of adding raw materials to the second furnace in Example 1 of the present application.

[0030] Figure 5 This is a schematic diagram of the alternating process of the forming mold of the first furnace and the second forming mold in Example 1 of the present application.

[0031] Figure 6 This is a schematic diagram of the cooling process of the forming mold in the first furnace and the starting process of raw material melting in the second furnace in Example 1 of the present application.

[0032] Figure 7This is a flow chart of the steps of the method for preparing cast tungsten carbide alloy according to Example 2 of the present application.

[0033] Among them, 1. furnace body; 11. smelting chamber; 12. mold chamber; 13. first valve; 14. discharge barrel; 2. smelting crucible; 3. forming mold; 4. smelting induction coil; 5. mold frame; 6. first observation hole; 7. second observation hole; 8. feeding chamber; 81. second valve; 9. top cover; 101. first horizontal push rod; 102. second horizontal push rod; 103. lifting push rod. DETAILED DESCRIPTION

[0034] In order to better understand the above technical solution, the above technical solution will be described in detail below in conjunction with the accompanying drawings and specific implementation methods.

[0035] Example 1

[0036] The embodiment of the present invention provides an apparatus for preparing a cast tungsten carbide alloy, which is applied to a method for preparing a cast tungsten carbide alloy provided in another embodiment of the present invention, referring to Figure 1 , including a furnace body 1, in which a smelting chamber 11 and a mold chamber 12 are arranged horizontally side by side and connected to each other, and a first valve 13 is provided at the connection between the smelting chamber 11 and the mold chamber 12, and the opening and closing of the connection between the smelting chamber 11 and the mold chamber 12 can be controlled by the first valve 13. An opening is provided on the side wall of the furnace body 1 at the mold chamber 12, and a furnace door for opening and closing the opening of the mold chamber 12 is provided outside the furnace body 1. A discharge barrel 14 is connected to the top of the furnace body 1, and the discharge barrel 14 is externally connected to a feeder. The top of the furnace body 1 is located on one side of the discharge barrel 14, and is also provided with a first observation hole 6, which is directly opposite to the upper opening of the smelting crucible 2, so that the staff can observe the smelting condition of the raw materials in the smelting crucible 2.

[0037] A smelting crucible 2 is arranged in the smelting chamber 11 of the furnace body 1. The smelting crucible 2 is rotatably mounted in the furnace body 1 through a bracket. The smelting crucible 2 is located directly below the material discharge. When the smelting crucible 2 is rotated to face upward, the material discharge barrel 14 faces the opening of the smelting crucible 2. The rotating shaft of the smelting crucible 2 is extended outside the furnace body 1 and an external transmission motor is connected to drive the smelting crucible 2 to turn over in the smelting chamber 11. A smelting induction coil 4 is wound around the outer wall of the smelting crucible 2. When the smelting induction coil 4 is energized, the raw materials in the smelting crucible 2 can be magnetically suspended and heated.

[0038] A mold support is fixedly arranged on the side of the melting crucible 2 where it is turned over and poured in the melting chamber 11. The mold support should be lower than the melting crucible 2. The mold support is used to place the forming mold 3. When the melting crucible 2 is turned over and poured, the molten raw materials in the crucible are poured into the forming mold 3. A mold transfer system for transferring the forming mold 3 between the mold chamber 12 and the mold support 5 is arranged in the furnace body 1.

[0039] Pour W powder and WC powder raw materials into the melting crucible 2 through the discharge barrel 14, start the melting induction coil 4, so that the raw materials are suspended in the melting crucible 2 and gradually heated up. The staff observes the melting state of the raw materials in the melting crucible 2 at any time through the first observation hole 6. When the staff observes that the raw materials are completely melted, the melting crucible 2 is controlled to be dumped, and the molten metal after the raw materials are melted is poured into the forming mold 3 on the mold support. Then, the forming mold 3 on the mold support is moved into the mold chamber 12 by the mold transfer system, and the mold chamber 12 is combined with the manual operation tool to drag and replace the empty forming mold 3 sent to the melting chamber 11 for replacement. After the raw materials are cooled and formed in the forming mold 3 in the mold chamber 12, the staff can take out the forming mold 3 from the mold chamber 12 and demold the cast tungsten carbide alloy block.

[0040] Specifically, thermocouples can be respectively arranged in the melting chamber 11 and the mold chamber 12 to obtain the temperature in the melting chamber 11 and the mold chamber 12. In the embodiment of the present application, the mold moving system includes a first horizontal push rod 101, a second horizontal push rod 102 and a lifting push rod 103. The first horizontal push rod 101 and the second horizontal push rod 102 are coaxial and opposite to each other along the mold. The arrangement direction of the tool frame and the mold chamber 12 is respectively arranged on the side walls of the melting chamber 11 and the mold chamber 12. The first horizontal push rod 101 and the second horizontal push rod 102 can control the extension length of the piston rod through a control terminal such as a computer, so as to cooperate with the clamping of the forming mold 3 placed on the mold frame 5, and move the forming mold 3 horizontally into the mold chamber 12. The lifting push rod 103 is set on the bottom wall of the mold chamber 12. After the first horizontal push rod 101 and the second horizontal push rod 102 work together to move the molding mold 3 to the piston rod extended by the lifting push rod 103, the piston rod of the lifting push rod 103 is lowered, so that the molding mold 3 descends smoothly, making it convenient for the staff to pull and drag the molding mold 3.

[0041] When pouring the molten metal in the melting crucible 2 into the forming mold 3, in order to prevent the molten metal from overflowing on the forming mold 3, in the embodiment of the present application, a second observation hole 7 is provided on the side wall of the furnace body 1 close to the mold frame 5, through which the pouring of the raw materials in the melting crucible 2 can be observed, which can effectively prevent the overflowing molten metal from damaging the inner wall of the furnace body 1.

[0042] In order to further protect the furnace body 1, in the embodiment of the present application, a cooling system is also provided in the furnace body 1, and the cooling system includes a cooling water flow channel. The furnace wall of the furnace body 1 is set as a double-layer structure, and the cooling water flow channel is set in the interlayer of the furnace wall. The cooling flow channel is connected to the circulating cooling water system in the factory. Before the smelting crucible 2 smelts the raw materials, the cooling system is turned on to continuously pass circulating cooling water into the cooling flow channel to cool down the furnace wall. After the smelting starts, the furnace wall of the furnace body 1 can effectively isolate the heat, so as to facilitate the staff to move outside the furnace body 1 and observe the situation inside the furnace body 1, and at the same time, it also ensures that the various parts of the furnace body 1 are not deformed or damaged by high temperature.

[0043] In the embodiment of the present application, the feeder includes a feeding chamber 8, which is arranged above the furnace body 1, the top of the feeding chamber 8 is open, and a top cover 9 for opening and closing the opening of the feeding chamber 8 is rotatably provided. The bottom of the feeding chamber 8 is connected to the discharge barrel 14, and a second valve 81 for opening and closing the discharge barrel 14 is provided below the feeding chamber 8. The staff adds raw materials into the feeding chamber 8, and when it is necessary to add raw materials to the melting crucible 2, the second valve 81 is opened, and the raw materials can automatically fall into the melting crucible 2. By setting up the feeder, the raw materials required for the next furnace can be added to the feeder in advance during the melting of one furnace of raw materials. After the raw materials of the previous furnace are poured and the melting crucible 2 is flipped and reset, the raw materials required for the next furnace can be released into the melting crucible 2, thereby improving the melting production efficiency of the cast tungsten carbide alloy. During the feeding process of the feeder, the upper cover 9 of the feeder is closed when feeding, so that the furnace body 1 can maintain sealed production, thereby improving the quality of the cast tungsten carbide alloy block.

[0044] The forming mold 3 is a graphite mold, which has good thermal conductivity and can improve the cooling efficiency of the molten metal in the graphite mold. Furthermore, a cooling channel can be set in the mold support so that the molten metal can be quickly cooled after being poured into the forming mold 3, effectively preventing the molten metal from sloshing and overflowing from the forming mold 3 when the mold transfer system transfers the forming mold 3, and improving the production efficiency of the cast tungsten carbide alloy block.

[0045] Reference Figure 2-6The working process of the present invention is as follows: after the W powder and WC powder raw materials are configured and pressed into blocks, the raw materials of the first furnace are put into the feeder, the second valve 81 is opened, and the raw materials of the first furnace are put into the melting crucible 2 in the furnace body 1. The melting induction coil 4 magnetically suspends and melts the raw materials in the melting crucible 2. After the staff confirms that all the raw materials of the first furnace are melted evenly, the melting crucible 2 is turned over to pour the molten metal into the forming mold 3 of the first furnace on the mold frame 5 in the melting chamber 11. Then the first valve 13 is opened, and the forming mold 3 of the first furnace is transferred to the mold chamber 12 through the mold transfer system, and the empty forming mold 3 of the second furnace placed in the mold chamber 12 in advance is transferred to the mold frame 5 in the melting furnace. At the same time, the top cover 9 on the feeder can be opened to feed the raw materials of the second furnace. After the mold transfer system is completed, the first valve 13 is closed, and the raw material smelting operation of the second furnace can be started in the smelting chamber 11. After the molten metal in the forming mold 3 of the first furnace in the mold chamber 12 is cooled to form the cast tungsten carbide alloy block, the forming mold 3 of the first furnace is taken out and put into the empty forming mold 3 of the next furnace, and the alloy block of the first furnace is demolded and taken out, and the finished cast tungsten carbide powder is obtained after being crushed by a crusher.

[0046] The melting crucible 2 is placed in the furnace body 1, and the whole melting process is surrounded by a protective atmosphere, which can make the melting process closed and effectively prevent the molten metal from being polluted by dust in the air. At the same time, during the electromagnetic suspension melting process, the melt overcomes gravity and suspends in the melting crucible 2, breaking away from the inner wall of the crucible, thereby obtaining high-temperature heating and effectively preventing the molten metal from being polluted by the melting crucible 2. The quality of the cast tungsten carbide powder products produced is greatly improved, and the working environment is greatly improved; the product quality is highly controllable and the physical properties are better.

[0047] Example 2

[0048] Reference Figure 7 The embodiment of the present invention provides a method for preparing a cast tungsten carbide alloy, comprising the following steps:

[0049] S01. According to the required ratio for casting tungsten carbide, W powder and WC powder are weighed and mixed as raw materials, and the raw materials are pressed into blocks. The mass proportion of C in the raw materials is 3.7-3.8%.

[0050] S02, prepare for smelting, start the chiller, continuously fill the cooling channel of the furnace body 1 with circulating cooling water, check and clean the electromagnetic suspension smelting equipment, install the smelting crucible 2, the mold, etc.;

[0051] A protective atmosphere is filled in the furnace body 1, and the block raw materials are sent into the melting crucible 2 of the electromagnetic suspension melting equipment under the protective atmosphere. The high-frequency power supply is started and the high-frequency current is increased. The high temperature generated by the electromagnetic induction effect of the melting induction coil is used to melt the block raw materials. The protective atmosphere is protected by nitrogen. The electromagnetic suspension melting equipment uses electromagnetic induction to control the heating temperature of the raw materials to 2500-3000°C.

[0052] S03. The staff observes the melting condition of the raw materials in the melting crucible 2 through the first observation hole 6 on the furnace body 1. After the staff determines that the materials are completely melted based on their experience, they are poured into the forming mold 3, the high-frequency power supply is turned off, and the cooling system is turned off.

[0053] S04, open the first valve 13, transfer the forming mold 3 into the mold chamber 12 and let it stand and cool for 30 to 40 minutes. After the casting is completely cooled, take the forming mold 3 out of the furnace body 1 and demould it to obtain a cast tungsten carbide alloy block;

[0054] S05. After the cast tungsten carbide alloy blocks are collected, they are crushed by a crusher and sieved to select the cast tungsten carbide powder that meets the requirements.

[0055] It should be understood by those skilled in the art that, although preferred embodiments of the present invention have been described, additional changes and modifications may be made to these embodiments once those skilled in the art are aware of the basic inventive concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present invention. Obviously, those skilled in the art may make various changes and modifications to the present invention without departing from the spirit and scope of the present invention. Thus, if these modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include these modifications and variations.

Claims

1. A device for preparing cast tungsten carbide alloy, characterized in that: Applicable to a method for preparing a cast tungsten carbide alloy, the method comprising: S01. According to the required ratio for casting tungsten carbide, weigh W powder and WC powder and mix them as raw materials, and press the raw materials into blocks; S02, feeding the bulk raw material into a melting crucible (2) of an electromagnetic suspension melting device under a protective atmosphere, and melting the bulk raw material by utilizing the high temperature generated by electromagnetic induction; S03, after the raw materials are completely melted and uniformly poured into a forming mold (3); S04, after the casting is cooled, the forming mold (3) is taken out from the smelting equipment, and demoulding is performed to obtain a cast tungsten carbide alloy block; S05. After the cast tungsten carbide alloy blocks are collected, they are crushed by a crusher and sieved to select the cast tungsten carbide powder that meets the requirements; The device comprises a furnace body (1), a smelting crucible (2) and a forming mold (3); a smelting chamber (11) and a mold chamber (12) are provided in the furnace body (1); the smelting crucible (2) is rotatably arranged in the smelting chamber (11) of the furnace body (1); a smelting induction coil (4) is wound around the outer wall of the smelting crucible (2); and a mold frame (5) for placing the forming mold (3) is provided on one side of the smelting crucible (2) in the smelting chamber (11); The top of the furnace body (1) is located directly above the smelting crucible (2) and is provided with a feeding barrel (14) for feeding materials. The top of the furnace body (1) is provided with a first observation hole (6) for observing the smelting conditions in the smelting crucible (2). The mold chamber (12) is located on one side of the smelting chamber (11). A first valve (13) is provided in the furnace body (1) at the connection between the smelting chamber (11) and the mold chamber (12). A mold transfer system for transferring the molding mold (3) between the mold chamber (12) and the mold frame (5) is provided in the furnace body (1). A furnace door for opening and closing the mold chamber (12) is provided on the furnace body (1); The mold transfer system comprises a first horizontal push rod (101), a second horizontal push rod (102) and a lifting push rod (103); the first horizontal push rod (101) and the second horizontal push rod (102) are respectively arranged on the side walls of the smelting chamber (11) and the mold chamber (12) along the arrangement direction of the mold frame (5) and the mold chamber (12); the push rods of the first horizontal push rod (101) and the second horizontal push rod (102) are coaxial and facing each other, and can clamp the molding mold (3) placed on the mold frame (5); the lifting push rod (103) is arranged on the bottom wall of the mold chamber (12); A feeding chamber (8) is arranged above the furnace body (1), the bottom of the feeding chamber (8) is connected to the discharge barrel (14), a second valve (81) for opening and closing the discharge barrel (14) is arranged below the feeding chamber (8), the top of the feeding chamber (8) is open, and a top cover (9) for opening and closing the opening of the feeding chamber (8) is rotatably arranged.

2. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: In step S01, the mass proportion of C in the raw material is 3.7-3.8%.

3. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: In step S02, the protective atmosphere is nitrogen.

4. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: In step S02, the electromagnetic suspension smelting equipment uses electromagnetic induction to control the heating temperature of the raw materials to 2500~3000℃.

5. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: In step S03, the staff observes the melting conditions of the raw materials in the crucible to ensure that the raw materials are completely and evenly melted.

6. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: It also includes a cooling system, the cooling system including a cooling water flow channel, the furnace wall of the furnace body (1) is arranged as a double-layer structure, the cooling water flow channel is arranged in the interlayer of the furnace wall of the furnace body (1), and the furnace body (1) is cooled by cooling water passing through the cooling water flow channel.

7. The device for preparing cast tungsten carbide alloy according to claim 1, characterized in that: A second observation hole (7) is provided on the side wall of the furnace body (1) close to the mold frame (5), and the pouring of raw materials in the melting crucible (2) can be observed through the second observation hole (7).

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