Anti-corrosion strengthening process and tool for chain wheel of slag salvaging machine

Abstract

The invention relates to an anti-corrosion strengthening process and tool for a chain wheel of a submerged chain conveyor. The chain wheel is made of a high-quality alloy material, and the internal structure and overall toughness of the chain wheel are strengthened through thermal refining; an oxygen-acetylene flame thermal spray welding technology is adopted, proper spray welding alloy powder is adopted, and a tooth surface transmission part of the chain wheel is subjected to full-coverage special treatment, so that the purposes of wear resistance, corrosion resistance and high temperature resistance are achieved; when an impact phenomenon is accidentally encountered in working condition operation and the tooth surface slips, the spray welding layer serving as a protective coating has the safety characteristics that friction sparks are not generated and the like; the whole set of tool is driven by an alternating-current motor worm gear reducer to achieve vertical linear stroke, so that the machined chain wheel is freely switched among the A station, the B station and the C station. And the control module drives the stepping motor planetary reducer, so that the chain wheel rotates according to the speed change set by the process. The hot spray welding process comprises the steps of sand blasting, preheating, spray welding and remelting, and the hardness of a spray welding layer can reach HRC59-63. And the chain wheel achieves the effect of'soft inside and steel outside '.

Description

Technical Field

[0001] This invention relates to the fields of coal and chemical machinery and equipment and thermal spraying (welding) technology. Background Technology

[0002] Coal chemical products are the foundation of modern industrial raw materials. As a key piece of equipment, the circular chain scraper slag remover plays an important role in the recycling and rational utilization of waste materials and environmental protection in the later stages of production.

[0003] Because chemical coal slag causes a certain degree of corrosion to the drive sprocket of the scraper slag remover, the equipment requires frequent maintenance, which greatly affects production. To address this, a corrosion-resistant and strengthening process and tooling for the slag remover sprocket have been invented to provide a solution. Summary of the Invention

[0004] The purpose of this invention is to provide a corrosion-resistant and strengthening process and tooling for slag removal machine sprockets, thereby improving the strength and corrosion resistance of the sprockets.

[0005] The technical solution adopted in this invention is as follows: High-quality alloy materials are used, and tempering treatment is applied to strengthen the internal structure and overall toughness of the sprocket; oxy-acetylene flame thermal spraying technology is employed, using suitable spraying alloy powder to fully cover the transmission part of the sprocket teeth with special treatment, achieving wear resistance, corrosion resistance, and high temperature resistance; In the event of accidental impact during operation, causing tooth slippage, the sprayed layer, as a protective coating, possesses safety characteristics such as not generating frictional sparks; the tooling consists of a motor reducer 1, a lifting nut 2, a lead screw 3, a tray 4, a positioning seat 5, a sprocket 6, a limit guide frame 7, a frame 8, a flange 9, and a motor reducer 1. The fixture consists of a remelting gun 11, a spray welding gun 12, a sandblasting gun 13, and a stepper motor control module D. A motor reducer 1 is fixed to the frame 8. The motor is a three-phase asynchronous motor, and the reducer is a worm gear reducer. The motor reducer 1 drives the lifting nut 2 to rotate bidirectionally, and the lead screw 3 moves up and down accordingly. The limit guide frame 7 restricts the rotation of the lead screw 3, allowing it to only move up and down. The motor reducer 10 is connected to the lead screw 3 via a flange 9 at the top and to the positioning seat 5 via its output shaft at the bottom. The tray 4 is a two-semicircle assembly, installed and inserted above the positioning seat 5, with the sprocket 6 placed on top of the tray 4. The entire fixture is driven by the motor reducer 1, allowing the sprocket 6 to freely switch between positions A, B, and C. The motor reducer 10 consists of a planetary reducer, a stepper motor, and a control module D. The output shaft of the motor reducer 10 drives the positioning seat 5 and the tray 4, causing the sprocket 6 to rotate according to the speed set in the process.

[0006] Furthermore, the sprocket material is made from raw materials containing the following weight percentages: carbon 0.43-0.48%, silicon 0.18-0.35%, manganese 0.55-0.76%, chromium ≤0.23%, nickel ≤0.25%, phosphorus ≤0.030%, sulfur ≤0.030%, and the remainder is iron.

[0007] Further, the base material processing steps are: forging billet → annealing → rough turning of the outer contour → gear making (according to process parameters) → quenching and tempering (HB: 255-285); Tooth surface spray welding process steps: After the sprocket cools down, remove surface oil and impurities → sandblast the tooth surface to roughen the surface → preheat (micro-carburizing flame, heated to about 300℃) → tooth surface spray welding (workpiece rotation) → remelting (neutral flame, 950-1050℃) → slow cooling (in insulation box) → inspection (appearance, weld thickness).

[0008] Furthermore, the selected spray welding alloy powder is prepared from raw materials containing the following weight percentages: carbon 0.90-0.98%, chromium 15.0-17.5%, boron 3.6-4.3%, silicon 3.6-4.3%, tungsten 9.5-11.5%, iron ≤12%, and the remainder being nickel. The hardness of the sprayed layer can reach HRC59-63. During the spray welding process, some chromium dissolves in nickel to form a solid solution, improving the alloy's oxidation resistance. The remaining chromium forms carbides and borides with carbon and boron, increasing the alloy's hardness. The alloy surface is very smooth after solidification, with a low coefficient of friction, and the uniformly distributed hard particles inside the alloy are highly wear-resistant. The alloy layer has strong resistance to corrosion from acids, alkalis, and salts. Combined with claims 2 and 3, the overall mechanical properties of the sprocket material are comprehensively improved. Boron and silicon can reduce the surface tension of the alloy melt, moderately enhance fluidity, and promote the rapid melting of the alloy melt onto the sprocket tooth surface.

[0009] Furthermore, in the tooling structure, the positioning seat 5 is machined with a deep groove M, and the pallet 4 is machined with a positioning protrusion K. The pallet 4 is cut into two equal halves through the center, and then they are assembled together. The positioning protrusion K of the pallet 4 is inserted into the deep groove M of the positioning seat 5 for positioning. The connection is simple, quick, and efficient. The H-flange positioning sprocket 6 of the pallet 4 ensures that its center coincides with the center of the lead screw 3.

[0010] Furthermore, position sensors A, B, and C are respectively installed at workstations A, B, and C; when the temperature reaches 300℃, the high-temperature transmitter C2 triggers relay C1 to drive the "arc extinguishing voice prompt"; when the temperature reaches 1050℃, the high-temperature transmitter C2 triggers relay C1 to drive the "cooling voice prompt"; when the temperature reaches 750℃, the high-temperature transmitter B2 triggers relay B1 to drive the "uniform powder feeding voice prompt"; when the set sandblasting time ends, relay A1 drives the "time voice prompt", and the sandblasting gun (13) stops sandblasting. The remelting gun 11 and the welding gun 12 are both connected to the pressurized air pipeline E, the oxygen pipeline F, and the acetylene gas pipeline G; the sandblasting gun 13 is connected to the pressurized air pipeline and the sand pipeline.

[0011] The beneficial effects of this invention are: the tooth surface of the sprocket can achieve wear resistance, corrosion resistance, and high temperature resistance, and the impact will not generate friction sparks and other safety features; thermal spraying (welding) technology is widely used in coal, chemical, metallurgical, aviation, aerospace and other fields.

[0012] The technical solution of the present invention will now be described in detail with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0013] Figure 1 This is a schematic diagram of the corrosion protection and reinforcement process and tooling composition of a slag removal machine sprocket according to the present invention; Figure 2 This is a pallet diagram of a corrosion-resistant and reinforcing process and tooling for a slag removal machine sprocket according to the present invention; Figure 3 This is a positioning seat diagram of a corrosion-resistant and strengthening process and tooling for a slag remover sprocket according to the present invention; In the diagram: 1. Motor reducer, 2. Lifting nut, 3. Lead screw, 4. Tray, 5. Positioning seat, 6. Sprocket, 7. Limiting guide frame, 8. Frame, 9. Flange, 10. Motor reducer, 11. Remelting gun, 12. Welding gun, 13. Sandblasting gun, D. Control module, A. Position sensor, B. Position sensor, C. Position sensor, C2. High temperature transmitter, C1. Relay, B2. High temperature transmitter, B1. Relay, A1. Relay, E. Pressure air pipeline, F. Oxygen pipeline, G. Acetylene pipeline. Detailed Implementation Sprocket base material processing: Material selection → Forging billet → Annealing → Rough turning of outer contour → Tooth making (allowing allowance according to process parameters) → Quenching and tempering (HB: 255-285); The preparation method involves drying and preheating the sprayed alloy powder at a temperature of 260-360℃. like Figure 1 As shown, the tooling is assembled based on frame 8; the pressurized air, oxygen, and acetylene gas must be dry and clean. The environmental dust suppression system is fully equipped.

[0014] like Figure 2 , Figure 3 As shown, combined with Figure 1 The sprocket 6 is threaded around the output shaft of the motor reducer 10. The two semicircles of the tray 4 are then installed and inserted above the positioning seat 5. The deep groove M of the positioning seat 5 and the positioning protrusion K of the tray 4 are engaged together. The sprocket 6 is placed above the tray 4. The H flange of the tray 4 positions the sprocket 6 to ensure that its center coincides with the center of the lead screw 3.

[0015] Motor reducer 1 drives lifting nut 2 to rotate, and lead screw 3 moves up and down accordingly. When sprocket 6 reaches station A, position sensor A sends a stop signal to the PLC module, and motor reducer 1 brakes and stops. Control module D drives motor reducer 10 in sandblasting mode, causing sprocket 6 to rotate. Sandblasting gun 13 is started, and sand particles are propelled by high-pressure air through the suction pipe from the nozzle of sandblasting gun 13 onto the rotating sprocket 6, achieving the effect of roughening the surface. Upon hearing the "time voice prompt," sandblasting stops based on the actual situation.

[0016] Then, the motor reducer 1 drives the sprocket 6 to the work station C. The position sensor C sends a stop signal to the PLC module, and the motor reducer 1 brakes and stops. The remelting gun 11 is ignited and preheats the sprocket 6 (sprocket rotation) with a micro-carbonizing flame. When the temperature reaches 300℃, the high temperature transmitter C2 triggers the relay C1 to drive the "arc extinguishing voice prompt" and extinguishes the arc in real time.

[0017] Next, the motor reducer 1 drives the sprocket 6 to station B. Position sensor B sends a stop signal to the PLC module, and the motor reducer 1 brakes and stops. The welding torch 12 is ignited, and the powder feeding switch is turned on. The welding torch 12 is used to spray weld on the sprocket 6 (as it rotates), applying a 0.1-0.15mm thick protective layer to prevent the substrate from being oxidized by the flame. The powder feeding switch is then paused, and the coating is heated with a flame. When the temperature reaches 760℃, the high-temperature transmitter B2 triggers relay B1, which provides a "uniform powder feeding voice prompt." Once the powder coating melts and exhibits a "mirror-like reflection," uniform powder feeding resumes. Welding is stopped when the coating thickness reaches 1.5-2.0mm. The thickness is estimated based on the powder feeding amount.

[0018] Next, the motor reducer 1 drives the sprocket 6 to position C. Position sensor C sends a stop signal to the PLC module, and the motor reducer 1 brakes and stops. The remelting torch 11 is ignited, remelting the sprayed weld layer on the sprocket 6 (where the sprocket rotates) using a neutral flame, controlled within the range of 950-1050°C, ensuring the temperature does not exceed 1050°C. When the temperature exceeds 1050°C, the high-temperature transmitter C2 triggers relay C1 to provide a "cooling voice prompt." The sprayed weld layer is heated to its melting temperature, completing the metallurgical bond between the sprayed weld layer and the base metal. The remelting temperature is typically above 1040°C. The remelted sprayed weld layer is quite dense, with almost no pores. The thickness of the sprayed weld layer is generally limited to a range that will not peel off when heated to its melting temperature. After remelting, all oxide residue should be removed.

[0019] The powder feed rate affects the weld layer structure and deposition efficiency. Insufficient heating of the raw material leads to a rapid decrease in efficiency, and the weld layer contains unmelted particles. If the powder feed rate is too low, some powder may volatilize, causing weld layer deterioration and increasing operating costs.

[0020] In summary, thermal spraying is a series of processes in which fine metallic or non-metallic coating materials, in a molten or semi-molten state, are deposited onto the surface of a prepared substrate to form a sprayed deposition layer.

[0021] The spray welding torch uses fuel gas to provide the necessary heat, heating the thermal spray material to a plastic or molten state. Compressed air then accelerates the material, propelling a constrained stream of particles that impacts the substrate surface. The impacted particles deform under pressure, forming laminated sheets that adhere to the prepared substrate surface. As they cool, they accumulate, eventually forming a layered weld layer. After remelting, the sprayed weld layer exhibits a strong and dense structure.

[0022] The flame of the fuel gas is used solely for melting the material, not for propelling or transporting the sprayed material. To achieve spray welding, a compressed airflow, typically formed from air, surrounds the flame, atomizing the molten material and propelling it onto the substrate. Spray welding does not cause overheating of the substrate, and the mechanical properties of the workpiece are not affected.

Claims

1. A corrosion-resistant and reinforcing process and tooling for a slag removal machine sprocket, characterized in that: High-quality alloy materials are used, and the internal structure and overall toughness of the sprocket are strengthened by tempering. Oxy-acetylene flame thermal spraying technology is adopted, and appropriate spraying alloy powder is used to fully cover the transmission part of the sprocket tooth surface with special treatment to achieve wear resistance, corrosion resistance and high temperature resistance. In the event of accidental impact during operation, the tooth surface slips. The sprayed layer, as a protective coating, has the safety characteristics of not generating friction sparks. The tooling consists of a motor reducer (1), lifting nut (2), lead screw (3), tray (4), positioning seat (5), sprocket (6), limit guide frame (7), frame (8), flange (9), motor reducer (10), remelting gun (11), spraying gun (12), sandblasting gun (13), and stepper motor control module D. The motor reducer (1) is fixed on the frame (8). The motor is a three-phase asynchronous motor, and the reducer is a worm gear reducer. The device, the motor reducer (1) drives the lifting nut (2) to rotate in both directions, the lead screw (3) moves up and down accordingly, the limit guide frame (7) restricts the rotation of the lead screw (3) so that the lead screw (3) only moves up and down; the motor reducer (10) is connected to the lead screw (3) above through the flange (9), and connected to the positioning seat (5) below through the output shaft of the motor reducer (10); the tray (4) is two semicircles, installed and inserted above the positioning seat (5), and the sprocket (6) is placed above the tray (4); the whole set of tooling is driven by the motor reducer (1), so that the position of the sprocket (6) can be freely switched between the three work positions A, B, and C; the motor reducer (10) consists of a planetary reducer, a stepper motor and a control module D, and drives the positioning seat (5) and the tray (4) through the output shaft of the motor reducer (10), so that the sprocket (6) rotates according to the speed set by the process.

2. The corrosion protection and reinforcement process and tooling for a slag removal machine sprocket according to claim 1, characterized in that: The sprocket material is made from raw materials containing the following weight percentages: carbon 0.43-0.48%, silicon 0.18-0.35%, manganese 0.55-0.76%, chromium ≤0.23%, nickel ≤0.25%, phosphorus ≤0.030%, sulfur ≤0.030%, and the remainder is iron.

3. The corrosion protection and reinforcement process and tooling for a slag removal machine sprocket according to claim 1, characterized in that: Sprocket base material processing steps: forging billet → annealing → rough turning of outer contour → tooth making (according to process parameters) → quenching and tempering (HB: 255-285); Tooth surface spray welding process steps: After the sprocket cools down, remove surface oil and impurities → sandblast the tooth surface to roughen the surface → preheat (micro-carburizing flame, heated to about 300℃) → tooth surface spray welding (workpiece rotation) → remelting (neutral flame, 950-1050℃) → slow cooling (in insulation box) → inspection (appearance, weld thickness).

4. The corrosion protection and reinforcement process and tooling for a slag removal machine sprocket according to claim 3, characterized in that: The selected spray welding alloy powder is prepared from raw materials containing the following weight percentages: carbon 0.90-0.98%, chromium 15.0-17.5%, boron 3.6-4.3%, silicon 3.6-4.3%, tungsten 9.5-11.5%, iron ≤12%, and the remainder is nickel. The hardness of the sprayed layer can reach HRC59-63. During the spray welding process, some chromium dissolves in nickel to form a solid solution, which improves the alloy's oxidation resistance. The remaining chromium forms carbides and borides with carbon and boron, which improves the alloy's hardness. The alloy surface is very smooth after solidification, with a low coefficient of friction, and the uniformly distributed hard particles inside the alloy are very wear-resistant. The alloy layer has strong resistance to corrosion from acids, alkalis, and salts. In conjunction with claims 2 and 3, the overall mechanical properties of the sprocket material are comprehensively improved. Boron and silicon can reduce the surface tension of the alloy melt, moderately enhance fluidity, and promote the rapid melting of the alloy melt onto the sprocket tooth surface.

5. The corrosion protection and reinforcement process and tooling for a slag removal machine sprocket according to claim 1, characterized in that: In the tooling structure, the positioning seat (5) is machined with a deep groove M, and the pallet (4) is machined with a positioning protrusion K. The pallet (4) is cut into two equal halves through the center and then put together. The positioning protrusion K of the pallet (4) is inserted into the deep groove M of the positioning seat (5) for positioning. The connection is simple, quick and efficient. The H flange positioning sprocket (6) of the pallet (4) ensures that its center coincides with the center of the lead screw (3).

6. The corrosion protection and strengthening process and tooling for a slag removal machine sprocket according to claim 1, characterized in that: Position sensors A, B, and C are installed at workstations A, B, and C, respectively. When the temperature reaches 300℃, the high-temperature transmitter C2 triggers relay C1 to drive the "arc extinguishing voice prompt". When the temperature reaches 1050℃, the high-temperature transmitter C2 triggers relay C1 to drive the "cooling voice prompt". When the temperature reaches 750℃, the high-temperature transmitter B2 triggers relay B1 to drive the "uniform powder feeding voice prompt". When the set sandblasting time ends, the relay A1 drives the "time voice prompt", and the sandblasting gun (13) stops sandblasting. The remelting gun (11) and the welding gun (12) are connected to the pressurized air pipeline E, the oxygen pipeline F, and the acetylene gas pipeline G. The sandblasting gun (13) is connected to the pressurized air pipeline and the sand pipeline.

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