Efficient curing device and method for epoxy powder coating of steel jacking pipe

Abstract

The invention discloses an efficient curing device and method for an epoxy powder coating of a steel jacking pipe, and relates to the technical field of pipeline engineering anti-corrosion construction. The device comprises a diameter-adjustable annular support, an annular infrared heating lamp set and a temperature control module, the support can be matched with a DN1200-DN2000 top pipe, the lamp set conducts directed radiation heating, and the temperature control module conducts precise temperature control; the method comprises the steps of pipe jacking pretreatment, coating, device installation, heating curing, detection and supplementary coating, cooling and acceptance inspection. The problems that the epoxy powder coating is low in curing efficiency and uneven in temperature in the low-temperature environment are solved, the surface drying time of the DN1200-DN2000 jacking pipe coating is shortened to be within 2 hours from 6 hours or above, the adhesive force of the coating is larger than or equal to 10 MPa, the method is suitable for low-temperature field construction at the temperature ranging from-20 DEG C to 10 DEG C, and the efficiency and quality of jacking pipe anti-corrosion construction are improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of pipeline engineering anticorrosion construction, and in particular to a high-efficiency curing device for epoxy powder coating of steel pipe jacking and a method thereof. BACKGROUND

[0002] In the pipeline network construction projects such as urban water supply and oil and gas transportation, the large-diameter steel pipe jacking technology is widely used in underground pipeline laying due to its advantages of effectively avoiding ground obstacles, small disturbance to the surrounding environment, and high construction efficiency. The epoxy powder coating has become the preferred material for the outer anticorrosion layer of the steel pipe jacking due to its excellent anticorrosion performance, chemical corrosion resistance, and adhesion performance.

[0003] However, the outdoor site construction of the steel pipe jacking is greatly affected by the environmental temperature, especially in the winter low-temperature environment (temperature below 0℃), the natural curing efficiency of the epoxy powder coating is greatly reduced. In the prior art, the curing methods of the epoxy powder coating mainly include natural drying and hot air heating: the natural drying completely depends on the environmental conditions, and the surface drying time often exceeds 6 hours in the low-temperature environment, and even the natural drying cannot be achieved, which seriously restricts the continuous construction efficiency of the pipe jacking; although the hot air heating can accelerate the curing to a certain extent, it has the following defects: on the one hand, the hot air heating has high energy consumption, serious heat loss, and low heating efficiency; on the other hand, the hot air flows unevenly in the complex weld area, resulting in uneven temperature distribution of the coating, and the problems of local overburning (coating yellowing and cracking) or insufficient curing (poor adhesion) are prone to occur, and the hot air heating cannot be adapted to steel pipe jacking of different diameters, and has poor universality. SUMMARY

[0004] In view of the deficiencies in the prior art, the present application provides a high-efficiency curing device for epoxy powder coating of steel pipe jacking and a method thereof, which aims to solve the problems of low natural curing efficiency, long surface drying time, high energy consumption of hot air heating, much heat loss, poor temperature uniformity, easy overburning or insufficient curing of the coating, and poor universality in the prior art.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solutions: A high-efficiency curing device for epoxy powder coating of steel pipe jacking and a method thereof, comprising an adjustable-diameter annular support, an annular infrared heating lamp group, and a temperature control module: The adjustable-diameter annular support comprises an annular main frame, a radial adjusting assembly, and a driving mechanism, the radial adjusting assembly is uniformly distributed along the circumference of the annular main frame, and the driving mechanism is in transmission connection with the radial adjusting assembly and is used to drive the radial adjusting assembly to move towards the center of the annular main frame; The annular infrared heating lamp group is fixed to one side of the radial adjusting assembly close to the steel pipe jacking, and the annular infrared heating lamp group is arranged in an annular array, and the radiation angle of each infrared heating lamp 21 can be adjusted in the range of 30°~90°. The temperature control module comprises a plurality of temperature sensors and a PID controller, the temperature sensors are uniformly distributed on the inner side of the adjustable radial annular support along the circumferential direction of the annular main frame, one end of the PID controller is electrically connected with the temperature sensor, and the other end is electrically connected with the annular infrared heating lamp group.

[0006] Further, the radial adjusting assembly is provided with at least 12 groups, and is distributed at equal intervals along the circumferential direction of the annular main frame, the number of infrared heating lamps 21 of the annular infrared heating lamp group is consistent with the number of radial adjusting assemblies, and is fixed on the radial adjusting assembly one by one.

[0007] Further, the inner side of the adjustable radial annular support is also provided with a reflector, the reflector is arranged on the inner side surface of the annular main frame and the radial adjusting assembly, and the reflection surface of the reflector faces the radiation direction of the annular infrared heating lamp group, and the reflectivity of the reflector is greater than or equal to 90%.

[0008] Further, the temperature sensors and the annular infrared heating lamp group are alternately distributed along the circumferential direction of the annular main frame, and the detection range of each temperature sensor covers the coating area of the steel pipe jacking corresponding to the adjacent two infrared heating lamps 21.

[0009] Further, the adjustable radial annular support can be divided into two parts, the upper and lower two parts of the annular main frame are detachably connected through bolts, and the upper and lower two parts are correspondingly provided with part of the structure of the radial adjusting assembly, the driving mechanism and the annular infrared heating lamp group.

[0010] The application also provides a high-efficiency curing method for the epoxy powder coating of the steel pipe jacking, which uses the curing device described above and comprises the following steps: (1) Steel pipe jacking pretreatment: when the steel pipe jacking is delivered, 100mm wide coating-free reserved area and bevel are reserved at both ends, the bevels of two steel pipe jacking sections are butt-jointed and welded, and the welds and the coating-free reserved area are cleaned after welding; 2) Epoxy powder coating: after the coating-free reserved area and the overlapping surface of the steel pipe jacking with the anticorrosive coating are treated, the epoxy powder anticorrosive coating is coated on the welds and the coating-free reserved area, and the coating is repeatedly brushed until the flow phenomenon appears on the coating surface; (3) Installation of the curing device: the high-efficiency curing device is installed on the outside of the welds of the steel pipe jacking, the radial adjusting assembly is driven to move by the driving mechanism, and the distance between the infrared heating lamps 21 of the annular infrared heating lamp group and the surface of the steel pipe jacking is adjusted to 0.2~0.5m; (4) Heating and curing: Start the ring infrared heating lamp group and heat it to a constant temperature range of 180~200℃ at a rate of ≤20℃ / min, and then maintain a constant temperature of 200℃; during the constant temperature process, the temperature of the coating surface is collected in real time by the temperature sensor and the temperature signal is transmitted to the PID controller. If the coating surface temperature exceeds 220℃, the PID controller controls the ring infrared heating lamp group to reduce the power, and the temperature difference of the coating surface is controlled to be ≤±10℃ throughout the process. (5) Thickness detection and touch-up coating: During the heating process, after the coating surface is dry, the coating thickness is detected. For areas that do not reach the design thickness, epoxy powder anti-corrosion coating is applied. After the touch-up coating is completed, the temperature is kept constant until all coatings in the annular area are completely dry and the thickness reaches the design value. (6) Cooling and acceptance: Turn off the ring infrared heating lamp group and allow the coating to cool down naturally. After cooling, the coating is inspected for quality.

[0011] Furthermore, the surface cleaning in step (1) includes rust removal, grinding, oil removal and welding slag removal in sequence. After the surface cleaning is completed, the weld is subjected to non-destructive testing.

[0012] Furthermore, the overlapping surfaces are roughened during the process, with the roughening width extending ≥20mm beyond the overlapping edge. After applying the epoxy powder anti-corrosion coating, the overlap width between the coating and the existing anti-corrosion layer is ≥50mm.

[0013] Furthermore, when checking the coating thickness during the process, at least 12 points in total are checked, including the top, bottom, left and right sides, 45° above and 45° below the steel jacking pipe. At the same time, the coating thickness is checked at the weld and the edges of the coating on both sides.

[0014] Furthermore, the quality acceptance process includes thickness acceptance and adhesion acceptance. Thickness acceptance requires that the thickness at any point tested is not less than the design value. Adhesion acceptance uses the cross-cut test and the adhesion is ≥10MPa.

[0015] Compared with the prior art, the present invention has the following beneficial effects: (1) Significantly shorten curing time: By using the directional radiation heating of the ring infrared heating lamp group, combined with the reflector to reduce heat loss, and with the precise temperature control of the PID controller, the surface drying time of the epoxy powder coating of DN1200~DN2000 steel jacking pipe in low temperature environment (below 0℃) is shortened from more than 6 hours to less than 2 hours, which significantly improves construction efficiency.

[0016] (2) Stable curing quality: The temperature sensor and PID controller work together to control the temperature difference of the coating surface ≤ ±10℃ throughout the process, avoiding local overheating or insufficient curing, ensuring that the coating adhesion is stable at ≥10MPa and the thickness is uniform and meets the standard.

[0017] (3) Strong adaptability and operability: The adjustable diameter ring support can be adapted to jacking pipes of different diameters from DN1200 to DN2000 through the radial adjustment component, and can be disassembled into upper and lower parts, which is convenient for on-site installation and disassembly in the field; there are no dead angles in temperature monitoring during the heating process, and the coating thickness detection covers key areas, further ensuring construction quality.

[0018] (4) Adaptable to low temperature environment: The device can still operate stably in the low temperature field environment of -20℃ to 10℃, solving the problem of anti-corrosion construction of pipe jacking in winter. Compared with hot air heating, energy consumption is reduced by 25% to 35%, which is more energy-saving and environmentally friendly. Attached Figure Description

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments: Figure 1 This is a flowchart of the high-efficiency curing method described in this invention; Figure 2 This is a schematic diagram of the structure of a ring-shaped heating device; Figure 3 This is a schematic diagram of the construction inside the working well; Figure 4 A schematic diagram showing the arrangement of pipes and a ring-shaped heating device; The components include: adjustable diameter ring support 1, ring main frame 11, radial adjustment component 12, drive mechanism 13, ring infrared heating lamp group 2, infrared heating lamp 21, temperature sensor 31, PID controller 32, jacking pipe 4, anti-corrosion coating 41, guide rail 5, and support 6. Detailed Implementation

[0020] To make the technical means, creative features, objectives and effects of this invention easier to understand, the invention will be further described below with reference to specific illustrations.

[0021] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0022] Example 1 Implementation of high-efficiency curing equipment (1) Adjustable diameter ring support 1 like Figures 2-4As shown, the adjustable diameter annular support 1 has an annular main frame 11 made of welded steel. The whole can be divided into upper and lower parts, each of which is semi-circular. The ends of the annular main frame 11 of the upper and lower parts are provided with flanges, which can be detachably connected by 4 sets of bolts, which facilitates installation on the outside of the weld of the steel jacking pipe. Twelve sets of radial adjustment components 12 are evenly spaced along the circumference of the inner side of the annular main frame 11. Each set of radial adjustment components 12 includes a slide rod and a slider. One end of the slide rod is fixedly connected to the annular main frame 11, and the other end extends radially toward the steel jacking pipe. The slider is sleeved on the slide rod and can slide along the slide rod. The drive mechanism 13 adopts hydraulic cylinders, a total of 12 sets. One end of each set of hydraulic cylinders is fixed to the annular main frame 11, and the other end is connected to the slider. The slider is driven by hydraulic pressure to move along the slide rod, thereby driving the annular infrared heating lamp group 2 to move closer to or away from the surface of the steel jacking pipe.

[0023] (2) Ring infrared heating lamp group 2 and reflector like Figure 3 As shown, the annular infrared heating lamp group 2 includes 12 infrared heating lamps 21. Each infrared heating lamp 21 is fixed to the side of the slider of a radial adjustment component 12 near the steel top pipe, arranged in a circular array, with a central angle of 45° between adjacent lamps. Each infrared heating lamp 21 is equipped with an angle adjustment bracket. By rotating the adjustment bracket, the radiation angle of the lamp can be adjusted within the range of 30° to 90°. For the weld area, the radiation angle can be adjusted to 60° to ensure that the heat is concentrated and covers the weld coating. A reflector is attached to the inner surface of the annular main frame 11 and the inner surface of the slider of the radial adjustment component 12. The reflector is made of polished metal with a reflectivity of 92%. Its reflective surface faces the radiation direction of the infrared heating lamp 21, which can reflect the heat radiated by the lamp to the outside back to the coating surface, reducing the heat loss to the surrounding environment.

[0024] (3) Temperature control module like Figure 3 As shown, the temperature control module includes 12 sets of temperature sensors 31 and one PID controller 32. The 12 sets of temperature sensors 31 are evenly spaced along the circumference of the annular main frame 11 and are alternately arranged with 12 infrared heating lamps 21 (i.e., one set of temperature sensors 31 is placed between two adjacent lamps). Each set of temperature sensors 31 is fixed to the inner side of the annular main frame 11 by a bracket, with its detection probe facing the coating surface of the steel jacking pipe. The detection range can cover the coating area corresponding to two adjacent lamps, ensuring no blind spots in temperature monitoring. The PID controller 32 is installed in a control box on the outside of the annular main frame 11 and is electrically connected to the 12 sets of temperature sensors 31 and the 12 infrared heating lamps 21 via cables. It can receive the temperature signals transmitted by the temperature sensors 31 in real time and adjust the lamp power according to the signal output control commands.

[0025] Example 2 Implementation of efficient curing methods Taking the construction of a DN1600 steel pipe jacking project in a city's water supply system as an example, the steel pipe is made of Q235B steel with a wall thickness of 16mm. The epoxy powder coating is designed to be 800μm thick, and the construction environment temperature is -5℃ (low-temperature outdoor environment in winter). Figure 1 As shown, the specific implementation steps are as follows: (1) Pretreatment of steel pipe jacking The steel jacking pipes are manufactured with 100mm wide uncoated pre-reserved areas and double bevels (inner bevel at the bottom, outer bevel at the top) at both ends, and each jacking pipe section is 6m long. During on-site construction, two jacking pipe sections are hoisted onto guide rail 5 inside the jacking shaft, aligning the bevels at both ends, and welded using gas shielded welding. After welding, the weld seam and uncoated pre-reserved areas are cleaned: first, sandblasting is used to remove rust to a Sa2.5 grade; then, an angle grinder is used to grind the weld seam and uncoated areas to remove weld beads and rough protrusions, ensuring the surface roughness meets the coating requirements; next, the surface is wiped with a cotton cloth dampened with detergent to remove oil stains; finally, a wire brush is used to remove residual weld slag. After surface cleaning, 100% non-destructive testing of the weld seam is performed using radiographic testing equipment to ensure that the weld seam is free of defects such as cracks and porosity.

[0026] (2) Epoxy powder coating Before applying the coating, the overlap surface between the uncoated reserved area and the existing anti-corrosion layer of the jacking pipe is roughened with sandpaper, with the roughening width extending 25mm beyond the overlap edge to ensure a rough surface for easy coating adhesion. Then, epoxy powder anti-corrosion coating is prepared on-site, and the coating and hardener are mixed in the correct proportions. After thorough stirring, the coating is applied to the weld and uncoated reserved area using a roller, repeating three times. After the first coat, wait for the surface to partially dry before applying the second coat, and then wait for it to partially dry before applying the third coat. This process continues until the coating surface shows signs of flow after the third coat, and the overlap width between the coating and the existing anti-corrosion layer is 55mm, meeting the requirement of ≥50mm.

[0027] (3) Installation of curing device like Figure 2 As shown, the upper and lower parts of the adjustable diameter annular support 1 are respectively fitted over the weld seam of the steel jacking pipe, aligning the center of the support with the axis of the jacking pipe. Then, the upper and lower parts of the support are spliced ​​and fixed by bolts on the flange. The hydraulic drive mechanism 13 is started, controlling 12 sets of hydraulic cylinders to push the slider along the slide rod, which moves the infrared heating lamp 21 closer to the surface of the jacking pipe. The distance between the lamp and the surface of the jacking pipe is observed through the scale on the support until the distance is adjusted to 0.3m, at which point the drive stops.

[0028] (4) Heating and curing The PID controller 32 and the ring-shaped infrared heating lamp group 2 are started, and the heating rate is set to 15℃ / min (≤20℃ / min). The temperature rises from the initial ambient temperature of -5℃, taking about 14 minutes to reach 200℃, after which it enters the constant temperature stage. During the constant temperature process, 12 temperature sensors 31 collect the coating surface temperature in real time and transmit the temperature signal to the PID controller 32. The PID controller 32 displays the temperature of each area in real time. When the temperature of a certain area exceeds 220℃, the PID controller 32 automatically outputs a command to reduce the power of the lamp beads in the corresponding area; when the temperature is below 190℃, the PID controller 32 increases the lamp bead power. Throughout the process, the temperature difference of the coating surface is controlled within ±8℃ (≤±10℃) to avoid overheating or insufficient curing of the coating.

[0029] (5) Thickness inspection and touch-up coating After heating for 30 minutes, the coating surface was observed to be dry. The lamp assembly was then turned off, and heating was paused. A film thickness gauge was used to check the coating thickness. During the test, one test point was selected in each of the 12 directions around the jacking pipe, and two test points were selected at the center of the weld and at both edges where the coating meets the existing anti-corrosion layer. Each point was measured three times, and the average value was taken. The test results showed that the thicknesses at the two points on the top of the jacking pipe were 760μm and 770μm respectively (not reaching the design value of 800μm), while the thicknesses at the remaining points were all between 800 and 830μm (meeting the standard). For the top points that did not meet the standard, epoxy powder coating was applied again, with a thickness of approximately 40μm. After the application was completed, the lamp assembly was restarted, and the temperature was maintained at 200℃ for another 20 minutes. The thickness was measured again, and the thickness at the top points all reached over 800μm. The coating thickness in all areas met the standard.

[0030] Turn off the ring-shaped infrared heating lamp group 2, unscrew the bolts on the bracket flange, disassemble the upper and lower parts of the bracket and remove them from the jacking pipe, allowing the coating to cool naturally. After the coating temperature drops to ambient temperature (-5℃), conduct quality acceptance: For thickness acceptance, re-test the thickness at all the above points, and the results should not be less than 800μm; for adhesion acceptance, use the cross-cut method, use a cross-cut knife to make a cross grid on the coating surface with a grid spacing of 2mm, then stick tape to the grid area and quickly peel it off, observe that the coating does not peel off, and then use a tensile testing device to test the adhesion, the test result is 11.5MPa (≥10MPa). The coating surface is free of defects such as bubbles, runs, and cracks, and the acceptance is qualified. After the acceptance is qualified, start the jacking equipment to jack the jacking pipe section to the designed distance, and then hoist the next jacking pipe section, repeating the above steps for construction.

[0031] Working principle: The high-efficiency curing device achieves efficient coating curing through the synergistic effect of "adjustable diameter adaptation - directional heating - precise temperature control": The drive mechanism 13 of the adjustable diameter ring bracket 1 drives the radial adjustment component 12 to move, so that the ring infrared heating lamp group 2 can adjust the distance between itself and the pipe surface according to the diameter of the steel jacking pipe (DN1200~DN2000), ensuring that the heating distance is stable within the optimal range of 0.2~0.5m; The ring infrared heating lamp group 2 is arranged in an array and the radiation angle is adjustable, which can directionally radiate heat to the surface of the coating in the weld and uncoated areas. With the help of the inner reflector to reflect heat, heat loss is reduced and heating efficiency is improved; The temperature sensor 31 collects the coating surface temperature in real time and transmits the signal to the PID controller 32. The PID controller 32 compares the difference between the actual temperature and the set constant temperature (200℃), and adjusts the lamp power to control the temperature difference within ±10℃, avoiding overheating or insufficient curing of the coating and ensuring curing quality.

[0032] The high-efficiency curing method achieves high-efficiency curing based on the logic of "pretreatment to ensure the foundation - coating to ensure bonding - heating to accelerate curing - inspection and touch-up coating to improve quality - acceptance to control quality": In the pretreatment stage, leaving uncoated areas facilitates welding, and surface cleaning and weld flaw detection ensure that the coating substrate is free of defects, providing a good foundation for coating adhesion; In the coating stage, roughening the overlapping surfaces enhances the bonding force between the coating and the existing anti-corrosion layer, and repeated brushing until it reaches a flow state ensures that the initial coating thickness is uniform; In the heating and curing stage, directional infrared heating rapidly raises the coating temperature to the required curing temperature of 180~200℃, and the constant temperature environment accelerates the cross-linking reaction between epoxy powder and curing agent, shortening the curing time; In the inspection and touch-up coating stage, to address the problem of uneven coating thickness that may occur in low-temperature environments, multi-point inspection and touch-up coating are used to ensure that the thickness of the entire area meets the standard; In the acceptance stage, thickness and adhesion testing are used to ultimately ensure that the coating curing quality meets the engineering requirements, achieving efficient and high-quality curing of epoxy powder coatings for steel jacking pipes in low-temperature environments.

[0033] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit it. Although the present invention has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications or equivalent substitutions can be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention, and all such modifications or substitutions should be covered within the scope of the claims of the present invention.

Claims

1. A high-efficiency curing device for epoxy powder coating on steel jacking pipes, characterized in that, Includes an adjustable diameter ring bracket (1), a ring infrared heating lamp assembly (2), and a temperature control module: The adjustable diameter ring support (1) includes a ring main frame (11), a radial adjustment component (12) and a drive mechanism (13). The radial adjustment component (12) is evenly distributed around the ring main frame (11). The drive mechanism (13) is connected to the radial adjustment component (12) and is used to drive the radial adjustment component (12) to move towards the center of the ring main frame (11). The annular infrared heating lamp group (2) is fixed on the side of the radial adjustment component (12) close to the steel jacking pipe (4), and the annular infrared heating lamp group (2) is arranged in a ring array. The radiation angle of each infrared heating lamp (21) can be adjusted within the range of 30°~90°. The temperature control module includes multiple temperature sensors (31) and a PID controller (32). The temperature sensors (31) are evenly distributed around the inner side of the adjustable diameter ring bracket (1) along the circumference of the ring main frame (11). One end of the PID controller (32) is electrically connected to the temperature sensor (31), and the other end is electrically connected to the ring infrared heating lamp group (2).

2. The high-efficiency curing device for epoxy powder coating of steel jacking pipe as described in claim 1, characterized in that, The radial adjustment assembly (12) is provided in at least 12 groups and is distributed at equal intervals along the circumference of the annular main frame (11). The number of infrared heating lamps (21) in the annular infrared heating lamp group (2) is the same as the number of radial adjustment assemblies (12) and is fixed on the radial adjustment assembly (12) in a one-to-one correspondence.

3. The high-efficiency curing device for epoxy powder coating of steel jacking pipe as described in claim 1, characterized in that, The adjustable diameter ring bracket (1) is also provided with a reflector on the inner side. The reflector is attached to the inner surface of the ring main frame (11) and the radial adjustment component (12), and the reflective surface of the reflector faces the radiation direction of the ring infrared heating lamp group (2). The reflector has a reflectivity of ≥90%.

4. The high-efficiency curing device for epoxy powder coating of steel jacking pipe as described in claim 1, characterized in that, The temperature sensor (31) and the annular infrared heating lamp group (2) are alternately distributed along the circumference of the annular main frame (11). The detection range of each temperature sensor (31) covers the coating area of ​​the steel jacking pipe (4) corresponding to two adjacent infrared heating lamps (21).

5. The high-efficiency curing device for epoxy powder coating of steel jacking pipe as described in claim 1, characterized in that, The adjustable diameter ring bracket (1) can be split into upper and lower parts. The upper and lower ring main frames (11) are detachably connected by bolts, and the upper and lower parts are respectively provided with radial adjustment components (12), drive mechanism (13) and ring infrared heating lamp group (2).

6. A highly efficient curing method for epoxy powder coating on steel jacking pipes, characterized in that, Using the curing apparatus as described in any one of claims 1 to 5, the method includes the following steps: (1) Steel jacking pipe pretreatment: When the steel jacking pipe (4) leaves the factory, a 100mm wide uncoated reserved area (41) and a bevel are reserved at both ends. On site, the bevels of the two steel jacking pipes (4) are joined and welded. After welding, the weld and the uncoated reserved area (41) are cleaned. 2) Epoxy powder coating: After treating the overlap surface of the uncoated reserved area (41) and the existing anti-corrosion layer of the steel jacking pipe (4), epoxy powder anti-corrosion coating is applied to the weld and the uncoated reserved area (41), and the coating is repeatedly brushed until the surface of the coating shows flow. (3) Installation of curing device: Install a high-efficiency curing device on the outside of the weld of the steel jacking pipe (4). Drive the radial adjustment component (12) to move through the drive mechanism (13) so that the distance between the infrared heating lamp 21 (21) of the ring infrared heating lamp group (2) and the surface of the steel jacking pipe (4) is adjusted to 0.2 to 0.5 m. (4) Heating and curing: Start the ring infrared heating lamp group (2) and heat it to a constant temperature range of 180~200℃ at a rate of ≤20℃ / min, and then maintain a constant temperature of 200℃; during the constant temperature process, the temperature of the coating surface is collected in real time by the temperature sensor (31) and the temperature signal is transmitted to the PID controller (32). If the coating surface temperature exceeds 220℃, the PID controller (32) controls the ring infrared heating lamp group (2) to reduce the power and controls the temperature difference of the coating surface ≤±10℃ throughout the process. (5) Thickness detection and touch-up coating: During the heating process, after the coating surface is dry, the coating thickness is detected. For areas that do not reach the design thickness, epoxy powder anti-corrosion coating is applied. After the touch-up coating is completed, the temperature is kept constant until all coatings in the annular area are completely dry and the thickness reaches the design value. (6) Cooling and acceptance: Turn off the ring infrared heating lamp group (2) to allow the coating to cool down naturally. After cooling, the coating is inspected for quality.

7. The efficient curing method for epoxy powder coating on steel jacking pipes as described in claim 6, characterized in that, The surface cleaning in step (1) includes rust removal, grinding, oil removal and welding slag removal in sequence. After the surface cleaning is completed, the weld is subjected to non-destructive testing.

8. The efficient curing method for epoxy powder coating on steel jacking pipes as described in claim 6, characterized in that, In step (2), the overlapping surface is roughened, the roughening width exceeds the overlapping edge by ≥20mm, and after applying epoxy powder anti-corrosion coating, the overlap width between the coating and the existing anti-corrosion layer is ≥50mm.

9. The efficient curing method for epoxy powder coating on steel jacking pipes as described in claim 6, characterized in that, When testing the coating thickness in step (5), at least 12 points in 12 directions are tested, including the top, bottom, left and right sides, 45° above and 45° below the steel jacking pipe (4), and the coating thickness at the weld and the edges of the coating on both sides is also tested.

10. The efficient curing method for epoxy powder coating on steel jacking pipes as described in claim 6, characterized in that, In step (6), the quality acceptance includes thickness acceptance and adhesion acceptance. Thickness acceptance requires that the thickness at any point of the tested location is not less than the design value. Adhesion acceptance uses the cross-cut test and the adhesion is ≥10MPa.

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