High-precision stainless steel pipe machining device and machining method

Abstract

The invention discloses a high-precision stainless steel pipe machining device and method. The high-precision stainless steel pipe machining device comprises a box body used for pickling a steel pipe, a cover body detachably arranged on the top of the box body in a covering mode and a steel pipe support detachably arranged in the box body and used for containing the steel pipe. A guide frame used for limiting and containing a steel pipe support is arranged in the box, a liquid inlet pipe is arranged on the upper portion of one side of the box, and a liquid discharge pipe is arranged on the lower portion of the other side of the box. Turbulent flow units which are vertically positioned at two end parts are arranged in the box body; a plurality of steel pipe brackets are arranged, and the steel pipe brackets can be nested with one another; the steel pipe is detachably arranged on the steel pipe support. The machining method comprises the steps of S1, device debugging preparation, S2, steel pipe clamping, S3, sealing and liquid feeding, S4, turbulent flow pickling, S5, pickling aftertreatment and S6, machining device resetting. The pickling device has the advantages of being high in safety, convenient to use and relatively high in pickling efficiency.

Description

Technical Field

[0001] This invention relates to the field of stainless steel pipe manufacturing technology, and in particular to a high-precision stainless steel pipe processing device and processing method. Background Technology

[0002] Pickling is a common surface treatment method for stainless steel pipes. It involves immersing the stainless steel pipe in an acidic solution to remove oxide layers, oil stains, rust spots, and welding marks from the surface. Pickling creates conditions for subsequent passivation treatment, ensuring the formation of an effective passivation film and thus improving the corrosion resistance of the stainless steel pipe.

[0003] Existing pickling processes typically involve open pickling tanks where stainless steel pipes are placed using supports. This open environment leads to the evaporation and splashing of acidic solutions during pickling, affecting the external environment and endangering worker safety. Furthermore, existing supports are simple in structure, usually large supports of fixed specifications, making it impossible to adjust them according to the actual number of steel pipes. Regardless of the number, the entire support must be placed inside, which is inconvenient. Moreover, the acidic solution is usually in a static state during pickling, resulting in relatively low pickling efficiency for the steel pipes. Summary of the Invention

[0004] The purpose of this invention is to provide a high-precision stainless steel pipe processing device and method. This invention has the advantages of high safety, ease of use, and relatively higher pickling efficiency.

[0005] The technical solution of the present invention: A high-precision stainless steel pipe processing device includes a box for pickling steel pipes, a detachable cover on the top of the box, and a detachable steel pipe support inside the box for accommodating the steel pipes. The box contains a guide frame for limiting and accommodating the steel pipe support. An inlet pipe is located on the upper part of one side of the box, and a drain pipe is located on the lower part of the other side. The box contains vertically positioned baffle units at both ends. Multiple steel pipe supports are provided, and they can be stacked on top of each other. The steel pipes are detachably mounted on the steel pipe supports.

[0006] In the aforementioned high-precision stainless steel pipe processing device, the top of the box body is provided with a stepped mounting groove, and the bottom of the cover body is provided with a corresponding mounting protrusion. A sealing ring is provided between the mounting protrusion and the mounting groove. Multiple lifting rings are distributed on the top of the cover body, and the lifting rings are detachably connected to the lifting equipment through a hook.

[0007] In the aforementioned high-precision stainless steel pipe processing device, the guide frame includes a mounting base at the bottom and guide plates vertically mounted on the mounting base and located on the front and rear side walls of the housing; each guide plate has a vertically arranged guide groove on the side away from the side wall of the housing, and the guide groove corresponds to the steel pipe support to accommodate the steel pipe support.

[0008] In the aforementioned high-precision stainless steel pipe processing device, the turbulence unit includes a turbulence motor vertically mounted on the cover, a fixed block located at the bottom of the housing, a rotating shaft rotatably mounted on the fixed block, multiple turbulence plates evenly distributed on the rotating shaft, and a driven block located at the top of the rotating shaft; the output shaft end of the turbulence motor is connected to a drive block located inside the cover, and the drive block and the driven block are detachably connected to drive the driven block to rotate.

[0009] In the aforementioned high-precision stainless steel pipe processing device, the steel pipe support includes a pair of corresponding clamping plates, an adjustable connecting rod located at the bottom of the clamping plates and connected to the clamping plates, and a suspension block located on the outside of the clamping plates; the inner side of the clamping plates is provided with an arc-shaped part corresponding to the steel pipe; the upper part of the clamping plates is provided with a superimposed protrusion, and the lower part is provided with a superimposed groove corresponding to the superimposed protrusion; the suspension block is provided with a through hole in a vertical direction.

[0010] In the aforementioned high-precision stainless steel pipe processing device, the adjustable connecting rod includes a connecting main rod and telescopic pull rods that are rotatably adjustable at both ends. One end of the telescopic pull rod is detachably connected to the clamping plate, and the other end is threaded into the connecting main rod.

[0011] In the aforementioned high-precision stainless steel pipe processing device, the bottom outer side of the box is provided with a number of universal wheels correspondingly distributed, and the bottom center is provided with a liftable support base; a hydraulic pump is provided in the lower center of the box, and a number of vertically arranged hydraulic rods are evenly distributed outside the hydraulic pump; the hydraulic rods are connected to the hydraulic pump through hydraulic pipelines, the top of the hydraulic rods are connected to the box, and the bottom is connected to the support base, driving the support base to rise and fall.

[0012] A method for processing high-precision stainless steel tubes includes the following steps: S1. Equipment debugging preparation: Move the processing device to the designated processing area, lower the support base to make it fit the ground; adjust the adjustable connecting rod according to the specifications of the steel pipe to be processed, and adjust the spacing between the clamping plates to match the outer diameter of the steel pipe. S2. Steel pipe clamping: Place the steel pipes to be pickled one by one into the arc-shaped part of the clamping plate, and clamp the steel pipes by limiting their position; according to the number of steel pipes, assemble multiple steel pipe supports loaded with steel pipes by overlapping each other with the cooperation of overlapping protrusions and overlapping grooves to form a support group; use the hook of the hoisting equipment to connect with the through hole of the suspension block to hoist the support group into the box, so that the two sides of the steel pipe support are embedded in the guide groove of the guide frame, thus completing the limiting placement of the steel pipe support; S3. Sealing and Liquid Inlet: The cover is sealed and installed onto the tank; the pickling solution is injected through the liquid inlet pipe until the tank is completely submerged; S4. Turbulent Pickling: Start the turbulent motor, and the rotating shaft drives the turbulent plate to rotate, disturbing the pickling solution; control the pickling time to 10-30 minutes according to the thickness of the oxide layer on the steel pipe surface. S5. Post-pickling treatment: After pickling is completed, turn off the turbulence motor and discharge the waste liquid through the drain pipe; lift the support assembly out of the tank using hoisting equipment and perform subsequent cleaning and drying treatment to complete the pickling process; S6. Reset of processing device: After processing is completed, clean water is injected through the inlet pipe for cleaning, and then discharged through the outlet pipe; the support base rises off the ground, and the processing device is moved to the storage area by the casters to complete the reset.

[0013] In the aforementioned high-precision stainless steel pipe processing method, the pickling solution injected in step S3 is a mixed solution of nitric acid and hydrofluoric acid, wherein the concentration of nitric acid is 8-12%, the concentration of hydrofluoric acid is 2-5%, and the solution temperature is controlled at 20-40℃.

[0014] In the aforementioned high-precision stainless steel pipe processing method, the cleaning in step S5 is carried out by rinsing with clean water at a pressure of 0.3-0.5 MPa for 3-5 minutes; the drying is carried out by hot air drying at a temperature of 60-80℃ for 15-20 minutes.

[0015] Compared with the prior art, this application has the following beneficial effects; 1. Enhanced safety: Through the sealed fit between the tank and the cover, combined with the sealing ring between the mounting protrusion and the mounting groove, the splashing of acidic solution during pickling can be effectively prevented, thus preventing pollution to the external environment and protecting the personal safety of workers. This solves the safety hazards of traditional open pickling tanks. 2. Convenient and flexible to use: The steel pipe support can be stacked and assembled according to the number of steel pipes, eliminating the need for a large support of fixed specifications, thus reducing the space occupied by the equipment; the adjustable connecting rod can flexibly adjust the spacing of the clamping plates, adapting to different specifications of stainless steel pipes within a certain range, improving the applicability of the device; the universal wheels at the bottom of the box facilitate the movement of the device, and the support base is hydraulically driven to achieve stable fixation, balancing the convenience of movement and the stability of placement. 3. Superior pickling efficiency and quality: The turbulence unit drives the turbulence plate to rotate, creating a continuous flow of the pickling solution. Compared to traditional static pickling methods, this significantly improves the uniformity of contact between the solution and the steel pipe surface, accelerates the removal of oxide layers, oil stains, and other impurities, and shortens the pickling time. Simultaneously, the steel pipe support uses the arc-shaped part of the clamping plate to hold the steel pipe, increasing the exposed area of ​​the steel pipe, ensuring thorough pickling, improving the surface treatment quality of the stainless steel pipe, and laying a good foundation for subsequent passivation treatment. 4. Improved ease of operation: The lifting ring on the cover and the suspension block of the steel pipe support work together to connect the lifting equipment, which facilitates the opening and closing of the cover and the hoisting of the steel pipe support, reducing the intensity of manual labor; the liquid inlet pipe and the liquid outlet pipe are respectively located at the top and bottom of the tank, which facilitates the injection of pickling solution and the discharge of waste acid, simplifying the operation process.

[0016] Therefore, the present invention has the advantages of high safety, convenient use and relatively higher pickling efficiency. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the steel pipe after placement according to the present invention; Figure 3 This is a schematic diagram of the steel pipe support structure of the present invention.

[0018] The markings in the attached diagram are as follows: 1. Box body, 11. Inlet pipe, 12. Drain pipe, 13. Fixing block, 14. Caster wheel, 2. Cover, 21. Mounting protrusion, 22. Lifting ring, 3. Baffle motor, 31. Rotating shaft, 32. Driven block, 33. Baffle plate, 4. Guide frame, 5. Steel pipe support, 51. Clamping plate, 52. Stacking protrusion, 53. Adjustable connecting rod, 6. Suspension block, 8. Hydraulic pump, 81. Hydraulic rod, 82. Support base, 9. Steel pipe. Detailed Implementation

[0019] The present invention will be further described below with reference to the accompanying drawings and embodiments, but this should not be construed as limiting the present invention.

[0020] Example. A high-precision stainless steel tube processing device, such as... Figure 1-3 As shown, the system includes a box 1 for pickling steel pipes 9, a cover 2 detachably placed on top of the box 1, and a steel pipe support 5 detachably placed inside the box 1 to accommodate the steel pipes 9. The box 1 is equipped with a guide frame 4 for limiting and accommodating the steel pipe support 5. An inlet pipe 11 is provided on the upper part of one side of the box 1, and a drain pipe 12 is provided on the lower part of the other side. The box 1 is equipped with a flow-dispersing unit located vertically at both ends in the length direction. Multiple steel pipe supports 5 are provided, and the steel pipe supports 5 can be stacked on top of each other. The steel pipes 9 are detachably mounted on the steel pipe supports 5.

[0021] The top of the housing 1 is provided with a stepped mounting slot, and the bottom of the cover 2 is provided with a corresponding mounting protrusion 21. A sealing ring is provided between the mounting protrusion 21 and the mounting slot. Multiple lifting rings 22 are distributed on the top of the cover 2. The lifting rings 22 are detachably connected to the lifting equipment through a hook.

[0022] The guide frame 4 includes a mounting base at the bottom and guide plates vertically mounted on the mounting base and located on the front and rear side walls of the housing 1; each guide plate has a vertically arranged guide groove on the side away from the side wall of the housing 1, and the guide groove corresponds to and accommodates the steel pipe support 5.

[0023] The turbulence unit includes a turbulence motor 3 vertically mounted on the cover 2, a fixed block 13 located at the bottom of the box 1, a rotating shaft 31 rotatably mounted on the fixed block 13, multiple turbulence plates 33 evenly distributed on the rotating shaft 31, and a driven block 32 located at the top of the rotating shaft 31; the output shaft end of the turbulence motor 3 is connected to a drive block located inside the cover 2, and the drive block and the driven block 32 are detachably connected to drive the driven block 32 to rotate.

[0024] The baffle 33 consists of 3 groups of 4 pieces each. The baffle 33 is inclined at a 30° angle to the rotating shaft 31 to ensure uniform turbulence of the pickling solution.

[0025] The drive block and the driven block 32 are connected by a common structure. For example, the bottom of the drive block is provided with a cross-shaped slot, and the top of the driven block 32 is provided with a cross-shaped boss that matches the cross-shaped slot. The drive block is detachably connected to the driven block 32 by the engagement of the cross-shaped slot and the cross-shaped boss, thereby driving the driven block 32 to rotate.

[0026] The steel pipe support 5 includes a pair of corresponding clamping plates 51, an adjustable connecting rod 53 located at the bottom of the clamping plates 51 and connected to the clamping plates 51, and a suspension block 6 located on the outside of the clamping plates 51; the inner side of the clamping plates 51 is provided with an arc-shaped part corresponding to the steel pipe 9; the clamping plates 51 are provided with a superimposed protrusion 52 above and a superimposed groove corresponding to the superimposed protrusion 52 below; the suspension block 6 is provided with a through hole in a vertical direction.

[0027] The suspension blocks 6 can be connected in series by traction ropes or lifting ropes, and the steel pipe support 5 together with the steel pipe 9 can be hoisted by using hoisting equipment, thus facilitating the overall handling.

[0028] The adjustable connecting rod 53 includes a connecting main rod and telescopic rods that can be rotated and adjusted at both ends. One end of the telescopic rod is detachably connected to the clamping plate 51 through a flange or the like, and the other end is provided with an external thread and threaded into the connecting main rod with an internal thread. By rotating the telescopic rod, it can move along the axial direction of the connecting main rod, thereby adjusting the distance between the clamping plates 51.

[0029] By setting an adjustable connecting rod 53 with a telescopic and adjustable length, the spacing between the clamping plates 51 can be adjusted to a certain extent according to actual needs, so as to meet the installation requirements of steel pipes 9 of different specifications within a certain range and have wider applicability. The steel pipe support 5 uses a pair of clamping plates 51 to accommodate and clamp the steel pipe 9, increasing the exposed area of ​​the steel pipe 9, thereby ensuring that it can be fully pickled.

[0030] The bottom outer side of the box 1 is provided with a plurality of universal wheels 14, and the bottom center is provided with a liftable support base 82; the bottom center of the box 1 is provided with a hydraulic pump 8, and a plurality of vertically arranged hydraulic rods 81 are evenly distributed on the outside of the hydraulic pump 8; the hydraulic rods 81 are connected to the hydraulic pump 8 through hydraulic pipelines, the top of the hydraulic rods 81 are connected to the box 1, and the bottom is connected to the support base 82, driving the support base 82 to rise and fall.

[0031] The housing 1 is made of stainless steel in one piece with a wall thickness of 10mm, which has good acid corrosion resistance; both the inlet pipe 11 and the outlet pipe 12 are equipped with corrosion-resistant ball valves.

[0032] The hydraulic rod 81 has a stroke of 300mm and a rated thrust of 5t. Its top is connected to the bottom of the housing 1 via a hinged seat. The bottom of the support base 82 is covered with an anti-slip rubber pad to ensure the stability of the device when it is fixed.

[0033] A high-precision stainless steel tube processing method, the process is as follows: S1. Equipment debugging preparation: Move the device to the designated processing area using the casters 14 at the bottom of the housing 1, start the hydraulic pump 8, and drive the support base 82 to descend and fit with the ground through the hydraulic rod 81 to achieve stable fixation of the device; According to the specifications of the stainless steel pipe 9 to be processed, rotate the telescopic rod of the adjustable connecting rod 53 to adjust the distance between the pair of clamping plates 51 so that the arc-shaped part on the inner side of the clamping plate 51 matches the outer diameter of the steel pipe 9. S2. Steel pipe clamping: Place the steel pipes 9 to be pickled one by one into the arc-shaped part of the clamping plate 51, and clamp the steel pipes 9 by the clamping plate 51; according to the number of steel pipes 9, assemble multiple steel pipe supports 5 loaded with steel pipes 9 by overlapping each other through the cooperation of overlapping protrusions 52 and overlapping grooves to form a support group; use the hook of the hoisting equipment to connect with the through hole of the suspension block 6 to hoist the support group into the box 1, so that the two sides of the steel pipe support 5 are embedded in the guide groove of the guide frame 4, and the limited placement of the steel pipe support 5 is completed. S3. Sealing and liquid inlet: Align the mounting protrusion 21 at the bottom of the cover 2 with the mounting slot at the top of the box 1 and insert it. The sealing of the box 1 is achieved by the sealing ring between the slot and the protrusion. Inject the acid pickling solution of the preset concentration into the box 1 through the liquid inlet pipe 11 until the solution completely submerges all the steel pipes 9 to be processed. Then close the valve of the liquid inlet pipe 11. S4. Turbulent pickling: Start the turbulent motor 3 on the cover 2. The output shaft of the turbulent motor 3 drives the drive block to rotate. The drive block and the driven block 32 cooperate to drive the rotating shaft 31 to rotate on the fixed block 13, thereby driving the turbulent plate 33 on the rotating shaft 31 to rotate synchronously. During the rotation of the turbulent plate 33, the pickling solution in the tank 1 is turbulent, so that the solution continues to flow and fully contacts the surface of the steel pipe 9. During the pickling process, the pickling time is controlled to be 10-30 minutes according to the thickness of the oxide layer on the surface of the steel pipe 9. S5. Post-pickling treatment: After pickling, turn off the turbulence motor 3, open the valve of the drain pipe 12, discharge the waste acid solution in the tank 1 and treat it centrally; lift the support group out of the tank 1 using the hoisting equipment, remove the stacked steel pipe support 5, and take out the pickled steel pipes 9 one by one; place the steel pipes 9 in the clean water tank for rinsing to remove the residual acid on the surface, and then dry them to complete the pickling process of the stainless steel pipes. S6. Equipment Reset: After processing is completed, clean water is injected into the housing 1 through the liquid inlet pipe 11 for cleaning, and then discharged through the liquid outlet pipe 12; start the hydraulic pump 8 to drive the support base 82 to rise off the ground, and move the device to the storage area through the casters 14 to complete the equipment reset.

[0034] The pickling solution injected in step S3 is a mixed solution of nitric acid and hydrofluoric acid, wherein the concentration of nitric acid is 8-12% and the concentration of hydrofluoric acid is 2-5%, and the solution temperature is controlled at 20-40℃.

[0035] In step S5, the cleaning is done by rinsing with clean water at a pressure of 0.3-0.5 MPa for 3-5 minutes; the drying is done by hot air drying at a temperature of 60-80℃ for 15-20 minutes.

Claims

1. A high-precision stainless steel pipe processing device, characterized in that: It includes a box (1) for pickling steel pipe (9), a cover (2) that can be detachably placed on the top of the box (1), and a steel pipe support (5) that can be detachably placed inside the box (1) to accommodate the steel pipe (9); the box (1) is provided with a guide frame (4) for limiting and accommodating the steel pipe support (5), and an inlet pipe (11) is provided on the upper part of one side of the box (1), and a drain pipe (12) is provided on the lower part of the other side; the box (1) is provided with a vertical turbulence unit located at both ends; there are multiple steel pipe supports (5), and the steel pipe supports (5) can be stacked on each other; the steel pipe (9) can be detachably placed on the steel pipe support (5).

2. The high-precision stainless steel pipe processing device according to claim 1, characterized in that: The top of the box (1) is provided with a stepped mounting slot, and the bottom of the cover (2) is provided with a corresponding mounting protrusion (21). A sealing ring is provided between the mounting protrusion (21) and the mounting slot. Multiple lifting rings (22) are distributed on the top of the cover (2). The lifting rings (22) are detachably connected to the lifting equipment through a hook.

3. The high-precision stainless steel pipe processing device according to claim 1, characterized in that: The guide frame (4) includes a mounting base at the bottom and guide plates vertically mounted on the mounting base and located on the front and rear side walls of the box (1); each guide plate has a vertically arranged guide groove on the side away from the side wall of the box (1), and the guide groove corresponds to the steel pipe support (5) to accommodate the steel pipe support (5).

4. The high-precision stainless steel pipe processing device according to claim 1, characterized in that: The turbulence unit includes a turbulence motor (3) vertically mounted on the cover (2), a fixed block (13) located at the bottom of the box (1), a rotating shaft (31) rotatably mounted on the fixed block (13), multiple turbulence plates (33) evenly distributed on the rotating shaft (31) at an incline, and a driven block (32) located at the top of the rotating shaft (31). The output shaft of the turbulence motor (3) is connected to a drive block located inside the cover (2), and the drive block and the driven block (32) are detachably connected to drive the driven block (32) to rotate.

5. The high-precision stainless steel pipe processing device according to claim 1, characterized in that: The steel pipe support (5) includes a pair of corresponding clamping plates (51), an adjustable connecting rod (53) located at the bottom of the clamping plate (51) and connected to the clamping plate (51), and a suspension block (6) located on the outside of the clamping plate (51); the inner side of the clamping plate (51) is provided with an arc-shaped part corresponding to the steel pipe (9); the clamping plate (51) is provided with a superimposed protrusion (52) above and a superimposed groove corresponding to the superimposed protrusion (52) below; the suspension block (6) is provided with a through hole in a vertical direction.

6. The high-precision stainless steel pipe processing device according to claim 5, characterized in that: The adjustable connecting rod (53) includes a connecting main rod and telescopic rods that can be rotated and adjusted at both ends. One end of the telescopic rod is detachably connected to the clamping plate (51), and the other end is threaded into the connecting main rod.

7. The high-precision stainless steel pipe processing device according to claim 1, characterized in that: The box (1) has multiple casters (14) distributed on the outer side of the bottom, and a liftable support base (82) in the middle of the bottom; a hydraulic pump (8) is provided in the middle of the bottom of the box (1), and multiple vertically arranged hydraulic rods (81) are evenly distributed on the outside of the hydraulic pump (8); the hydraulic rods (81) are connected to the hydraulic pump (8) through hydraulic pipelines, the top of the hydraulic rods (81) is connected to the box (1), and the bottom is connected to the support base (82), driving the support base (82) to rise and fall.

8. A high-precision stainless steel pipe processing method according to any one of claims 1-7, characterized in that, The process includes the following steps: S1. Equipment debugging preparation: Move the processing device to the designated processing area, lower the support base (82) to make it fit with the ground; adjust the adjustable connecting rod (53) according to the specifications of the steel pipe (9) to be processed, and adjust the distance between the clamping plates (51) to match the outer diameter of the steel pipe (9); S2, Steel pipe (9) clamping: Place the steel pipe (9) to be pickled one by one into the arc-shaped part of the clamping plate (51), and clamp the steel pipe (9) by the clamping plate (51); According to the number of steel pipes (9), multiple steel pipe supports (5) loaded with steel pipes (9) are stacked together to form a support group by the cooperation of the overlapping protrusions (52) and the overlapping grooves; The support group is hoisted into the box (1) by connecting the hook of the hoisting equipment with the through hole of the suspension block (6), so that the two sides of the steel pipe support (5) are embedded in the guide groove of the guide frame (4) to complete the limited placement of the steel pipe support (5); S3, sealing and liquid inlet: The cover (2) is sealed and installed on the box (1); the pickling solution is injected through the liquid inlet pipe (11) until the steel pipe (9) to be processed is completely submerged. S4. Turbulent pickling: Start the turbulent motor (3), rotate the shaft (31) to drive the turbulent plate (33) to rotate and turbulent the pickling solution; control the pickling time to 10-30 minutes according to the thickness of the oxide layer on the surface of the steel pipe (9); S5. Post-pickling treatment: After pickling is completed, turn off the turbulence motor (3) and discharge the waste liquid through the drain pipe (12); lift the support group out of the box (1) through the hoisting equipment, and carry out subsequent water rinsing and hot air drying to complete the pickling. S6. Reset of processing device: After processing is completed, clean water is injected through the inlet pipe (11) for cleaning, and then discharged through the drain pipe (12); the support base (82) rises off the ground and the processing device is moved to the storage area by the casters (14) to complete the reset.

9. A method for processing high-precision stainless steel pipes according to claim 8, characterized in that: The pickling solution injected in step S3 is a mixed solution of nitric acid and hydrofluoric acid, wherein the concentration of nitric acid is 8-12% and the concentration of hydrofluoric acid is 2-5%, and the solution temperature is controlled at 20-40℃.

10. A method for processing high-precision stainless steel pipes according to claim 8, characterized in that: In step S5, the cleaning is done by rinsing with clean water at a pressure of 0.3-0.5 MPa for 3-5 minutes; the drying is done by hot air drying at a temperature of 60-80℃ for 15-20 minutes.

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