Manufacturing method for medium-frequency induction heating double-liquid composite casting of large wear-resistant lining plate

Abstract

The invention discloses a method for manufacturing a large wear-resistant lining plate through medium-frequency induction heating double-liquid composite casting. The method comprises the following steps that a vertical parting lost foam model with a metal partition plate is manufactured according to design requirements; hoisting the cylindrical sand box into a boss on a ground fixing bracket, putting the evanescent mode model into the cylindrical sand box, and sequentially filling sand into the cylindrical sand box, compacting by vibration and vacuumizing; alloy steel and high-chromium cast iron liquid are smelted in the two intermediate frequency furnaces to the discharging temperature; liquid is discharged from the casting ladles, and temperature measurement is prepared; the two kinds of liquid obtained after smelting are injected into a lost foam cavity at the same time; moving the medium-frequency induction heater to enable the heating coil to completely surround the side wall of the cylindrical sand box; a medium-frequency induction heater is started, induction heating is conducted on the cylindrical sand box, the heating power is 500 KW, the frequency is 900-1000 Hz, the temperature is 900-1150 DEG C, the temperature is kept for 3-10 min, and it is ensured that a bonding layer of the casting is fully fused; after heating is completed, the medium-frequency induction heater is moved out of and away from the cylindrical sand box; and the casting is taken out of the round sand box and cleaned.

Description

Technical Field

[0001] The invention relates to the technical field of casting, in particular to a method for manufacturing a large wear-resistant liner by medium-frequency induction heating and double-liquid composite casting. Background Art

[0002] Large ball mills, essential equipment for grinding materials, are widely used in various industrial fields requiring large-scale continuous production, such as mining, metallurgy, environmental protection and resource recovery, cement and building materials, and other fields. Liners in ball mills are classified by their location: cylinder lining, grinding head lining, and grinding door lining. These liners protect the cylinder, disperse the grinding media and material, and improve grinding efficiency. Liners are also classified by their material: metal-based linings, rubber linings, stone or cast stone linings, and composite material linings.

[0003] Currently, most ball mill liners are made of metal-based materials, with a small number made of non-metallic materials. Due to the different motion states of the grinding bodies in each chamber, different materials are used to manufacture the linings of each chamber to adapt to the requirements of this working state. In the crushing chamber, the grinding bodies are mainly subjected to impact, requiring the linings to have impact resistance and wear resistance. High manganese steel (ZGMn13) is commonly used as the lining material. It has a certain impact toughness and, when subjected to a certain impact, its surface undergoes cold work hardening, becoming hard and wear-resistant. The general hardness is HB300-350, with a very high toughness and an impact value of up to 700Nm / cm 2However, during use, it is easy to bend and deform prematurely, break the fixing bolts, cause the liner to fall off, and reduce its service life. The average lifespan is generally 5000-6000 hours. High chromium cast iron has high hardness and good wear resistance, ranking first among wear-resistant materials. High chromium cast iron is a brittle material. After proper treatment, it can be made into coarse grinding bin liners. High chromium cast iron is used under relatively small impact conditions, such as coal mill liners and crusher liners (wear plates). Its wear resistance is 6-8 times higher than that of high manganese steel, and the economic benefits are very significant. High chromium cast iron is not suitable for complex structures and thin-walled large parts on the mill, such as partition grate plates and grinding head liners. Now high chromium cast iron has developed into various grades and is generally widely used in the cement industry. In order to improve the toughness of wear-resistant materials, high chromium cast steel and other materials have emerged. Currently, wear-resistant materials can also be selected from low chromium cast iron, 42 silicon manganese chromium molybdenum steel, low carbon silicon manganese wear-resistant alloy steel, low alloy high strength steel, etc. In the fine grinding chamber, the grinding media is primarily abrasive, so the lining requires excellent wear resistance. Wear-resistant white cast iron, chilled cast iron, and medium-manganese rare earth ductile iron are available. Compared to high-manganese steel liners, rubber liners offer the following advantages: Lightweight, which reduces installation labor and maintenance time; light load, which reduces power consumption by approximately 10%; long service life, which improves mill operation efficiency; and reduces grinding media consumption by over 20%. They protect the cylinder from slurry abrasion, extending its service life; and produce low industrial noise, improving operating conditions and benefiting worker health. However, their disadvantages include poor heat resistance; unsuitable for dry grinding; and suboptimal impact resistance in the head chamber of a wet ball mill. There is also a type of lining made of diabase cast stone material. Some cement plants have used it in the final bin of the mill and have conducted industrial tests on the inlaid lining. The test results show that it is completely feasible to use it in the steel forging bin of the tube mill. Its service life is more than twice that of the self-cast white cast iron lining, and the cost is more than half that of white cast iron. However, the inlay technology of the cast stone lining and the casting quality of the cast stone itself need further research and improvement.

[0004] Large ball mill liners are still mainly made of a single wear-resistant material, high manganese steel or various alloy steel materials. Some bimetallic composite liners have been used in small ball mills. Due to the low strength and easy rheological properties of high manganese steel, it is less and less used in actual applications. Traditional alloy steel liners have insufficient material toughness and are difficult to achieve an effective balance between wear resistance and impact resistance. Double-liquid bimetallic composite liners improve performance by combining heterogeneous materials, but are limited by the inherent defects of the casting process (such as poor bonding layer stability and easy interface cracking). Currently, it is impossible to manufacture large double-liquid composite cast wear-resistant liners for large ball mills with good stability. During the cooling process, large castings are prone to large thermal stresses due to their large volume and slow cooling rate. The different shrinkage rates of the two metals may cause large residual stresses at the interface, which in turn causes cracking. Small castings have a fast cooling rate, which may result in smaller residual stresses and a more stable bonding layer. Therefore, it is urgent to propose a process method for manufacturing large double-liquid composite cast wear-resistant liners.

[0005] The disclosure of the above background technology content is only used to assist in understanding the concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of this application. Summary of the Invention

[0006] The purpose of the present invention is to propose a method for manufacturing large wear-resistant liners by medium-frequency induction heating double-liquid composite casting, so as to solve the technical problems of poor stability of the bonding layer and easy cracking of the interface of wear-resistant liners used in large ball mills in the above-mentioned prior art.

[0007] To this end, the present invention proposes a method for manufacturing a large wear-resistant liner by medium-frequency induction heating double-liquid composite casting. The present invention may also have the following technical features: comprising the following steps: (1) making a lost foam model: making a vertical parting lost foam model with a metal partition according to design requirements; (2) placing the lost foam model: hoisting a cylindrical sand box into a boss on a ground fixed bracket, placing the lost foam model into the cylindrical sand box, filling sand into the cylindrical sand box, vibrating, and vacuuming in turn; (3) preparing for molten steel melting: simultaneously smelting alloy steel and high chromium cast iron liquid in two medium-frequency furnaces according to composition and process requirements to the furnace discharge temperature; (4) preparing before pouring: pouring alloy steel and high chromium cast iron liquid into a ladle, and preparing for temperature measurement; (5) pouring: pouring the molten steel into the molten steel. The alloy steel and high chromium cast iron liquid are injected into the evaporative mold cavity at the same time; (6) Move the medium frequency induction heater to a suitable position: By operating the control cabinet, move the medium frequency induction heater so that the heating coil in the medium frequency induction heater completely surrounds the side wall of the cylindrical sand box; (7) Medium frequency induction heating: Start the medium frequency induction heater to induction heat the cylindrical sand box with a heating power of 500KW, a frequency of 900-1000Hz, and a temperature of 900℃-1150℃. Maintain the temperature for 3-10 minutes to ensure that the bonding layer of the casting is fully fused; (8) Remove the medium frequency induction heater: After heating is completed, move the medium frequency induction heater so that it is moved out and away from the cylindrical sand box; (9) Cleaning: Take the casting out of the cylindrical sand box and clean it.

[0008] Specifically, before step (1), the method further includes using Q234 steel plates to make metal partitions, cutting them according to the outer dimensions of the wear-resistant lining plates, polishing the surfaces of the cut metal partitions, and then using hydrochloric acid preparations to perform rust removal treatment.

[0009] Specifically, step (1) includes using a special foam material for lost foam to make a lost foam model and a pouring system according to process requirements, and placing the metal partition at one-third of the distance from the liner installation surface in the thickness direction of the lost foam model; adding a coating on the surface of the lost foam model, and baking it at 40-50°C for 7-9 hours to dry and harden the coating.

[0010] Specifically, before step (2), the process also includes making a cylindrical sand box, which is made by welding stainless steel plates according to the size of the liner and process requirements.

[0011] Specifically, the outer diameter of the cylindrical sand box is 200 to 300 mm larger than the maximum outer dimension of the lost foam model, and the height is 400 to 600 mm higher than the maximum outer dimension of the lost foam model.

[0012] Specifically, the sand used for filling in step (2) is gem sand or silica sand.

[0013] Specifically, the induction heating temperature in step (7) is controlled by connecting a temperature measuring head pre-buried near the lost foam mold to a temperature controller.

[0014] Specifically, in step (8), the medium frequency induction heater is moved to its initial position.

[0015] Specifically, after the medium frequency induction heater is removed in step (8), the cylindrical sand box continues to maintain negative pressure, so that the casting is cooled to below 700°C and the liquid is completely solidified, and then the negative pressure can be stopped. After the casting is cooled to below 300°C, the casting can be taken out of the cylindrical sand box and cleaned.

[0016] Specifically, the cleaning includes cutting off the pouring system and riser after the casting is cooled to room temperature, and heat treating the casting. The heat treatment process includes heating the liner to 1000-1050°C, quenching, rapid air cooling, and then tempering at 200-300°C.

[0017] The beneficial effects of the present invention compared with the prior art include:

[0018] The method adopts medium frequency induction heating to manufacture large wear-resistant liners by double-liquid composite casting. Two liquids are used to cast the large wear-resistant liners. A metal partition is set in the middle of the lost foam model to effectively avoid the mutual penetration of the metal liquids on both sides during the pouring process, which affects the quality of the casting. A vertical pouring method is adopted to simultaneously inject the smelted alloy steel and high chromium cast iron liquids into the lost foam model cavity from the left and right sides of the metal partition, which effectively avoids the problem of poor bonding of the bonding layer caused by oxidation of the metal liquid surface. After the pouring is completed, the medium frequency induction heater is controlled to make the heating coil fully surround the side wall of the cylindrical sand box, and then medium frequency heating is started and the temperature is maintained for 3 to 10 minutes (the specific heating time is determined according to the size of the liner) to make the double-layer metal liquid fully melt and combine with the metal partition, avoiding the phenomenon of poor fusion of various areas due to uneven heat, which leads to unstable bonding layer and even cracking. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a first schematic diagram of a specific embodiment of the present invention.

[0020] Figure 2 It is a second schematic diagram of a specific embodiment of the present invention.

[0021] Figure 3 It is a left view of a specific embodiment of the present invention.

[0022] Figure 4 It is a first top view of a specific embodiment of the present invention.

[0023] Figure 5 It is a third schematic diagram of a specific embodiment of the present invention.

[0024] Figure 6 It is a second top view of a specific embodiment of the present invention.

[0025] Figure 7 It is an enlarged schematic diagram of the first schematic diagram A of a specific embodiment of the present invention.

[0026] Figure 8 It is a schematic diagram of a cylindrical sand box according to a specific embodiment of the present invention.

[0027] Figure 9 It is a schematic diagram of a lost foam model (provided with a metal partition) according to a specific embodiment of the present invention.

[0028] Figure 10 Schematic diagram of a high-frequency induction heater (with a counterweight) in a specific embodiment of the present invention.

[0029] Figure 11 1 is a top view of a high-frequency induction heater (with a counterweight) in a specific embodiment of the present invention.

[0030] Figure 12 Schematic diagram of the connection between the guide rail and the ball bearing in a specific embodiment of the present invention.

[0031] Figure 13 It is a schematic diagram of a ground fixing bracket in a specific embodiment of the present invention.

[0032] Explanation of reference numerals: 01-ground fixed bracket; 011-boss; 02-guide rail; 021-ball bearing; 03-cylindrical sand box; 31-negative pressure pipe; 32-negative pressure pipe interface; 33-lifting ear; 04-lost foam model; 41-gating system; 42-riser; 43-lining plate mounting surface; 05-metal partition; 06-movable bracket; 61-horizontal frame; 611-front beam; 612-rear beam; 613-left beam; 62-vertical frame; 621-upper beam; 622-lower beam; 623-front vertical beam; 624-rear vertical beam; 6 3-reinforcement plate; 07-medium frequency induction heater; 71-coil bracket; 72-heating coil; 73-connecting plate; 731-first fixing hole; 732-second fixing hole; 74-insulating plate; 75-first space; 08-first screw rod; 09-first motor; 10-coupling; 11-polished rod; 12-linear bearing; 13-counterweight; 14-second motor; 15-second screw rod; 16-fixed bracket crossbeam; 17-control cabinet; 18-controller; 19-first limit device; 20-second limit device; 21-vacuum pump. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings. It should be emphasized that the following description is merely illustrative and is not intended to limit the scope of the present invention and its application.

[0034] Non-limiting and non-exclusive embodiments will be described with reference to the following figures, wherein like reference numerals refer to like parts unless otherwise specifically specified.

[0035] A method for manufacturing a large wear-resistant liner by medium-frequency induction heating double-liquid composite casting, comprising the following steps: (1) making a lost foam model: making a vertical parting lost foam model with a metal partition according to design requirements; (2) placing the lost foam model: hoisting a cylindrical sand box onto a boss on a ground fixed bracket, placing the lost foam model into the cylindrical sand box, and sequentially filling sand into the cylindrical sand box, vibrating, and vacuuming; (3) preparing for molten steel melting: simultaneously smelting alloy steel and high-chromium cast iron liquid in two medium-frequency furnaces according to composition and process requirements to the furnace discharge temperature; (4) preparing before pouring: pouring the alloy steel and high-chromium cast iron liquid into a ladle, and preparing for temperature measurement; (5) pouring: pouring the smelted alloy steel and high-chromium cast iron liquid into the molten steel. At the same time, the evaporative mold cavity is injected; (6) Move the medium frequency induction heater to a suitable position: By operating the control cabinet, move the medium frequency induction heater so that the heating coil in the medium frequency induction heater completely surrounds the side wall of the cylindrical sand box; (7) Medium frequency induction heating: Start the medium frequency induction heater to induction heat the cylindrical sand box with a heating power of 500KW, a frequency of 900-1000Hz, and a temperature of 900℃-1150℃. Maintain the temperature for 3-10 minutes to ensure that the bonding layer of the casting is fully fused; (8) Remove the medium frequency induction heater: After heating is completed, move the medium frequency induction heater so that it is removed and away from the cylindrical sand box; (9) Cleaning: Take the casting out of the cylindrical sand box and clean it.

[0036] The present invention uses a manufacturing device for double-liquid composite casting of large wear-resistant liners and adopts the above-mentioned manufacturing method to manufacture double-liquid composite casting of large wear-resistant liners. It uses a vertical parting form, that is, a vertical pouring method, which is convenient for separating the castings according to any design requirements without affecting the thickness of the castings, and performs simultaneous pouring, which can effectively avoid the problem of poor bonding of the bonding layer caused by oxidation of the metal liquid surface; a medium-frequency induction heater is used to surround the side wall of the cylindrical sand box, and medium-frequency induction heating is performed to make the double-layer metal liquid fully melt and combine with the metal partition, avoiding the phenomenon of poor fusion of each area due to uneven heat, which leads to unstable bonding layer or even cracking.

[0037] Before step (1), the metal partition is made of Q234 steel plate. In actual production, a 3-8 mm steel plate can be selected according to the total weight and thickness of the wear-resistant lining plate, and the wear-resistant lining plate is cut according to the size of the wear-resistant lining plate. The surface of the cut metal partition is polished, and then a hydrochloric acid preparation is used for rust removal.

[0038] The above step (1) specifically includes using a special foam material for lost foam to produce a lost foam model and a pouring system according to the process requirements, and placing the metal partition at a distance of one-third from the liner installation surface (i.e., the non-working surface of the liner) in the thickness direction of the lost foam model; adding a coating to the surface of the lost foam model and baking it at 40-50°C for 7-9 hours to dry and harden the coating, specifically using a special coating for lost foam steel casting, and the coating thickness is 2-3 mm. The special foam material for lost foam can be a copolymer foam board or a copolymer foam white mold.

[0039] Before step (2), the cylindrical sand box is also made: according to the size of the liner and the process requirements, the cylindrical sand box is made by welding stainless steel plates, such as Figure 8 As shown, the cylindrical sand box is open, with several lifting lugs welded to its upper and side edges. Several interconnected negative pressure tubes are provided on the inner arms and bottom of the cylindrical sand box. The negative pressure tubes are symmetrically distributed and concentrated into a single channel. A negative pressure tube interface is provided on the outside of the sand box, allowing it to be connected to a vacuum pump to pump negative pressure into the cylindrical sand box. Specifically, the thickness of the stainless steel plate is 10 to 20 mm; the outer diameter of the cylindrical sand box is 200 to 300 mm larger than the maximum external dimension d of the lost foam model, and the height is 400 to 600 mm higher than the highest external dimension h of the lost foam model (including the height of the gating system and riser); the diameter of the negative pressure tube is 60 to 100 mm, the tube wall thickness is 2 to 4 mm, and negative pressure holes with a diameter of 1 to 2 mm are evenly distributed on the negative pressure tube, with a spacing of 3 to 5 mm.

[0040] In the above step (2), the sand filling is made of gem sand or silica sand. After the sand filling, the negative pressure system is turned on to form a "sand suction force" through the air pressure difference, accelerate the directional filling of sand particles, and discharge gas and debris at the same time. The sand is compacted using a three-dimensional vibration table, and the synergistic effect of negative pressure and vibration is used to improve the compactness of the sand mold and the quality of the casting.

[0041] The combination ratio of alloy steel and high chromium cast iron in the above step (3) is shown in the table below, wherein alloy steel is used to cast the liner mounting surface, i.e., the non-working surface, and high chromium cast iron is used to cast the wear-resistant surface, i.e., the working surface.

[0042]

[0043] The induction heating temperature in the above step (7) is controlled by connecting a temperature measuring head pre-buried near the lost foam model to a temperature controller. The specific heating time is determined according to the size of the lining plate to ensure that the bonding layer of the casting is fully fused.

[0044] In the above step (8), the medium frequency induction heater is moved to the initial position to facilitate the next medium frequency heating. The initial position can be set according to the specific production. The height direction is at least higher than the height of the cylindrical sand box. The horizontal direction is at least such that the medium frequency induction heater and the cylindrical sand box do not interfere with each other, which is convenient for pouring. Specifically, after removing the medium frequency induction heater, the cylindrical sand box continues to maintain negative pressure, so that the casting is cooled to below 700°C and the liquid is completely solidified, and then the negative pressure can be stopped. After the casting is cooled to below 300°C, the casting can be taken out of the cylindrical sand box and cleaned. The cleaning mentioned here includes: after the casting is cooled to room temperature, the pouring system and riser are cut off, and the casting is heat treated. The heat treatment process specifically includes heating the liner to 1000-1050°C, quenching treatment, rapid air cooling, and then tempering treatment at 200-300°C to reduce quenching stress and brittleness while maintaining a high hardness.

[0045] The equipment used in the above method is specifically a manufacturing device for a large wear-resistant liner by double-liquid composite casting, such as Figures 1 to 13 As shown, it includes a ground fixing bracket 01, a plurality of guide rails 02 are provided on its upper surface. In this embodiment, the ground fixing bracket 01 is fixed on the cement floor; a cylindrical sand box 03 is provided on the ground fixing bracket 01. Specifically, Figure 1 and 13 As shown, the cylindrical sand box 03 is placed at a specified position of the ground fixed bracket 01, that is, it is set on the boss 011 near the right end of the guide rail 02, and can be freely lifted from the ground fixed bracket 01 according to production needs. A vertically parted lost foam model 04 is provided in the cylindrical sand box 03, and a metal partition 05 is vertically provided in the middle of the lost foam model 04. The smelted alloy steel and high chromium cast iron liquid can be injected into the lost foam cavity from the left and right sides of the metal partition 05 respectively; the lost foam model 04 mentioned here is a model of a large wear-resistant liner, and the model and the casting system are made of lost foam special foam material (copolymer foam board or copolymer foam white mold) according to process requirements; a movable bracket 06 is set on the guide rail 02. Under the action of the driving mechanism, the movable bracket 06 can approach or move away from the cylindrical sand box 03, as shown in FIG. Figure 2 and 12As shown, the movable bracket 06 is slidably set on the guide rail 02 through a ball bearing 021; the medium frequency induction heater 07, which is set on the movable bracket 06, includes a coil bracket 71, a heating coil 72 and a connecting plate 73, and the coil bracket 71 is a cylindrical shape with upper and lower openings; the heating coil 72 is insulated from the coil bracket 71, and is arranged in the coil bracket 71 along the side wall of the coil bracket 71. There is a first space 75 for accommodating the cylindrical sand box 03 in the middle of the surrounded heating coil 72, and the heating coil 72 is connected to the control cabinet 17 through a water-cooling cable; the connecting plate 73 is horizontally arranged on the side of the coil bracket 71 close to the movable bracket 06, and the projection of the connecting plate 73 and the movable bracket 06 on the horizontal plane partially overlaps, and a first fixing hole 731 is correspondingly provided at the overlapping position, and a first screw rod 08 is provided through the first fixing hole 731, and a first motor 09 is connected to the first screw rod 08, so that the rotation of the first motor 09 can drive the medium frequency induction heater 07 to move up and down.

[0046] The above device is used to manufacture large wear-resistant linings cast by double-liquid composite casting, that is, two liquids are used to cast large wear-resistant linings. A metal partition 05 is set in the middle of the lost foam model 04, which can effectively prevent the metal liquids on both sides from penetrating each other during the pouring process, thereby affecting the quality of the casting; a vertical pouring method is adopted to simultaneously inject the smelted alloy steel and high chromium cast iron liquid into the lost foam model cavity from the left and right sides of the metal partition 05, which effectively avoids the problem of poor bonding of the bonding layer caused by oxidation of the metal liquid surface; after the pouring is completed, the medium frequency induction heater is driven by the driving mechanism. 07 is pushed to the top of the cylindrical sand box 03, and under the action of the first motor 09, the medium frequency induction heater 07 moves downward until the height of the heating coil 72 matches the height of the lost foam model 04 (including the casting system 41 and the riser 42 of the lost foam model 04), and then starts heating and maintains the temperature for 3 to 10 minutes (the specific heating time is determined by the size of the liner) to allow the double-layer metal liquid to fully melt and combine with the metal partition 05, avoiding the occurrence of poor fusion of various areas due to uneven heat, which leads to unstable bonding layer and even cracking.

[0047] Specifically, if Figure 9 As shown, the metal partition 05 is made of Q234 steel plate and is arranged along the thickness direction of the lost foam model 04. The distance from the liner mounting surface 43 (that is, the non-working surface of the liner) is one-third of the thickness of the lost foam model 04. The thickness of the metal partition 05 is selected according to the total weight and thickness of the liner, and is generally 3 to 8 mm thick. After the metal partition 05 is cut according to the shape of the liner, it is necessary to polish the surface and use hydrochloric acid to remove rust. Specifically, as Figure 2 and 8As shown, it also includes a vacuum negative pressure device, which includes a vacuum pump 21, a cooling water circulation device and a control device. A number of negative pressure pipes 31 are set along the inner wall and bottom of the cylindrical sand box 03. The negative pressure pipes 31 are symmetrically distributed, interconnected, and concentrated into a main channel. A negative pressure pipe interface 32 connected to the main channel is set outside the cylindrical sand box 03, so that the negative pressure pipe interface 32 is connected to the vacuum pump to pump negative pressure into the cylindrical sand box 03. In specific production, the negative pressure is pumped through the control device. In order to facilitate the lifting of the cylindrical sand box 03, a number of lifting ears 33 can also be set on the upper part and side of the cylindrical sand box 03. Figure 1 、 8 As shown in FIG9 , the outer diameter of the cylindrical sand box 03 is preferably the maximum outer dimension d+(200-300) mm of the lost foam model 04, and the height is preferably the highest outer dimension (including the height of the pouring system 41 and the riser 42) h+(400-600) mm of the lost foam model 04.

[0048] like Figure 1 and 7 As shown, the mobile bracket 06 includes a horizontal frame 61 and a vertical frame 62, which are welded from a plurality of steel plates. The horizontal frame 61 and the vertical frame 62 are combined into an "L" shape. The horizontal frame 61 includes a front beam 611, a rear beam 612 and a left beam 613. The vertical frame 62 includes an upper beam 621, a lower beam 622, a front vertical beam 623 and a rear vertical beam 624. Two guide rails 02 are provided on the ground-fixed bracket 01 corresponding to the positions of the front beam 611 and the rear beam 612 of the horizontal frame 61. In order to improve the overall stability of the mobile bracket 06, a plurality of reinforcing plates 63 can be provided between the horizontal frame 61 and the vertical frame 62. In this example, two reinforcing plates 63 are provided. Specifically, in order to improve the stability and balance of the entire device, the first fixing hole 731 is provided in the middle of the upper beam 621, the first motor 09 is provided on the upper beam 621, and the lower end of the first screw rod 08 is fixed to the connecting plate 73. The first motor 09 drives the medium frequency induction heater 07 to move up and down as a whole through the turbine screw structure. When the first motor 09 rotates, the rotational motion of the first motor 09 is transmitted to the first screw 08 through the coupling 10. By controlling the forward and reverse rotation of the first motor 09, the first screw 08 can be moved up and down to drive the connecting plate 73 to move up and down, and finally drive the medium frequency induction heater 07 to move up and down.

[0049] like Figure 1 、 10As shown in FIG11 , two second fixing holes 732 are correspondingly provided on the upper beam 621 and the connecting plate 73. The second fixing holes 732 are symmetrically provided on both sides of the first fixing hole 731 and are in a straight line with the first fixing hole 731. A light rod 11 is provided in the second fixing hole 732. The lower end of the light rod 11 is fixed to the connecting plate 73, and the upper end passes through the second fixing hole 732 of the upper beam 621. This structure plays a guiding role, making the medium frequency induction heater 07 move up and down more smoothly. Specifically, as shown in FIG11 Figure 1 and 7 As shown, a linear bearing 12 can be set in the second fixing hole 732 at the upper beam 621, and the optical rod 11 is set in the linear bearing 12, which can reduce the friction between the optical rod 11 and the connecting plate 73, improve the smoothness of movement, and make the optical rod 11 move up and down more smoothly, with high precision and long service life.

[0050] like Figure 1 As shown, in order to increase the overall stability of the device, a counterweight 13 can be set on the connecting plate 73, away from the medium frequency induction heater 07. The counterweight 13 is set on the left side of the upper beam 621. The weight of the counterweight 13 can be set according to the weight of the medium frequency induction heater 07. It is mainly to make the medium frequency induction heater 07 move up and down more smoothly. The specific weight of the counterweight is not limited.

[0051] like Figure 1 As shown, the driving mechanism includes a second motor 14 and a second screw rod 15. A fixed support beam 16 is provided on the side of the ground fixed support 01 away from the cylindrical sand box 03. The second motor 14 is provided on the fixed support beam 16. The second screw rod 15 is provided horizontally and is connected to the second motor 14 through a coupling. The right end of the second screw rod 15 is fixedly provided at the lower end of the movable support 06. During operation, the second motor 14 transmits its rotational motion to the second screw rod 15 through the coupling. By controlling the forward and reverse rotation of the second motor 14, the left and right movement of the movable support 06 is realized, and the movable support 06 is driven to be close to or away from the cylindrical sand box 03, so as to cover or move the medium frequency induction heater 07 out of the cylindrical sand box 03. It can be understood that, as Figure 5 and 6 As shown in FIG, when the medium frequency induction heater 07 is sheathed around the cylindrical sand box 03, the medium frequency induction heater 07 is in a heating state. Through induction heating, the alloy steel and high chromium cast iron liquid are fully melted and combined with the metal partition, thereby avoiding the occurrence of poor fusion of various areas due to uneven heat. Figure 1 、 2As shown in Figure 4, after heating is completed, the medium frequency induction heater 07 is removed from the cylindrical flask 03. Of course, the temperature of the newly heated casting is very high. In order to cool the cylindrical flask 03 and the casting inside and improve the cooling efficiency, a water cooling system can be set in the medium frequency induction heater 07. After heating is completed, the water cooling system is started to help the casting cool to a certain temperature (for example, 300°C) before the medium frequency induction heater 07 is removed. Of course, in order to make the movable bracket 06 move left and right more smoothly, polished rods can also be set on both sides of the second screw rod 15. The specific connection relationship is similar to that of the polished rods on both sides of the first screw rod, which will not be repeated here.

[0052] like Figure 10 and 11 As shown, the medium frequency induction heater 07 also includes an insulating plate 74, which is vertically arranged on the inner wall of the coil bracket 71. The heating coil 72 passes through the insulating plate 74 and is surrounded by the coil bracket 71. The insulating plate 4 serves to fix the heating coil 72 so that the heating coil 72 is at a certain distance from the heating bracket 71.

[0053] like Figure 1 As shown, it also includes a control cabinet 17, which is used to control the heating of the medium frequency induction heater 07, the movement of the first motor 09 and the second motor 14. Specifically, the relevant control actions can be integrated into a controller 18 for user operation. Specifically, an infrared limit device can also be set on the moving track of the mobile bracket 06 and the medium frequency induction heater 07, such as Figure 1 As shown, a first limiting device 19 is provided on the left side of the cylindrical sand box 03, near the cylindrical sand box 03, to control the extreme position of the movable bracket 06 moving to the right; a second limiting device 20 is provided on the lower part of the front vertical beam 623 or the rear vertical beam 624 of the movable bracket 06 to control the extreme position of the connecting plate 73 moving downward. The first limiting device 19 and the second limiting device 20 can be set according to specific needs to adapt to different production needs.

[0054] Those skilled in the art will recognize that numerous variations to the foregoing description are possible, and that the examples and figures are intended only to describe one or more specific implementations.

[0055] Although what is considered to be exemplary embodiments of the present invention has been described and illustrated, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt a particular situation to the teachings of the present invention without departing from the central concept of the invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but rather encompasses all embodiments and their equivalents falling within the scope of the present invention.

Claims

1. A method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting, characterized by: The method comprises the following steps: (1) making a lost foam model: making a vertical parting lost foam model with a metal partition according to the design requirements; (2) placing the lost foam model: hoisting a cylindrical sand box onto a boss on a fixed support on the ground, placing the lost foam model into the cylindrical sand box, and sequentially filling the cylindrical sand box with sand, vibrating, and evacuating; (3) preparing for molten steel melting: simultaneously smelting alloy steel and high chromium cast iron liquid in two medium frequency furnaces according to the composition and process requirements to the furnace discharge temperature; (4) preparing before pouring: pouring the alloy steel and high chromium cast iron liquid into the ladles, and preparing for temperature measurement; (5) pouring: injecting the smelted alloy steel and high chromium cast iron liquid into the lost foam model cavity at the same time; (6) Move the medium frequency induction heater to a suitable position: by operating the control cabinet, move the medium frequency induction heater so that the heating coil in the medium frequency induction heater completely surrounds the side wall of the cylindrical sand box; (7) Medium frequency induction heating: start the medium frequency induction heater to induction heat the cylindrical sand box with a heating power of 500KW, a frequency of 900-1000Hz, and a temperature of 900℃-1150℃. Maintain the temperature for 3-10 minutes to ensure that the bonding layer of the casting is fully fused; (8) Remove the medium frequency induction heater: after heating is completed, move the medium frequency induction heater so that it is removed and away from the cylindrical sand box; (9) Cleaning: remove the casting from the cylindrical sand box and clean it.

2. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double-liquid composite casting according to claim 1 is characterized in that: Before step (1), the method also includes using Q234 steel plate to make a metal partition, cutting it according to the outer dimensions of the wear-resistant liner, polishing the surface of the cut metal partition, and then using a hydrochloric acid preparation to remove rust.

3. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double-liquid composite casting according to claim 1 is characterized in that: Step (1) comprises using a special foam material for lost foam to make a lost foam model and a pouring system according to the process requirements, and placing the metal partition at a position one-third of the distance from the liner installation surface in the thickness direction of the lost foam model; adding a coating on the surface of the lost foam model, and baking it at 40 to 50° C. for 7 to 9 hours to dry and harden the coating.

4. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting according to claim 1 is characterized in that: Before step (2), the process also includes making a cylindrical sand box, which is made by welding stainless steel plates according to the size of the liner and process requirements.

5. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting according to claim 4 is characterized in that: The outer diameter of the cylindrical sand box is 200 to 300 mm larger than the maximum outer dimension of the lost foam model, and the height is 400 to 600 mm higher than the maximum outer dimension of the lost foam model.

6. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting according to claim 1 is characterized in that: In step (2), the sand used for filling is pearl sand or silica sand.

7. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting according to claim 1 is characterized in that: The induction heating temperature in step (7) is controlled by connecting a temperature measuring head pre-buried near the lost foam model to a temperature controller.

8. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and double liquid composite casting according to claim 1 is characterized in that: In step (8), the medium frequency induction heater is moved to its initial position.

9. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and two-liquid composite casting according to claim 1 is characterized in that: After removing the medium frequency induction heater in step (8), the cylindrical sand box continues to maintain negative pressure until the casting cools to below 700°C and the liquid is completely solidified. Then the negative pressure can be stopped. When the casting cools to below 300°C, the casting can be taken out of the cylindrical sand box and cleaned.

10. The method for manufacturing a large wear-resistant liner by medium frequency induction heating and two-liquid composite casting according to claim 9, characterized in that: The cleaning includes cutting off the pouring system and riser after the casting is cooled to room temperature, and heat treating the casting. The heat treatment process includes heating the liner to 1000-1050°C, quenching, rapid air cooling, and then tempering at 200-300°C.

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