Coating method for sintering epoxy heavy anti-corrosion coating on inner wall of large-length aluminum alloy thin-wall storage cabin

Abstract

The invention provides a large-length aluminum alloy thin-wall storage cabin inner wall sintering epoxy heavy anti-corrosion coating coating method which comprises the steps that S1, a silica gel heating belt is arranged on the outer wall of a storage cabin, the silica gel heating belt is started to heat the storage cabin, and heat preservation is conducted for a first process duration after the temperature is reached; s2, a spray gun is made to do one-way linear motion along the center axis of the storage bin, a spray head of the spray gun rotates with the center axis of the storage bin as the rotating center axis, and the inner wall of the storage bin is coated with a low-temperature curing and sintering epoxy heavy anti-corrosion coating; s3, keeping the heating state of the silica gel heating tape in the step S1 on the storage cabin, and preserving heat for a second process duration; according to the method, the sintering quality and the coating thickening efficiency of the sintered epoxy heavy anti-corrosion coating and the aluminum alloy thin-wall storage cabin are improved, the safety of the coating process is also improved, the inner wall coating process flow and related operation are greatly simplified, and the coating process cost is reduced.

Description

Technical Field

[0001] The invention relates to the field of preparation technology of heavy-duty anti-corrosion coating on the inner surface of a tank, and in particular to a method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a sintered epoxy heavy-duty anti-corrosion coating. Background Art

[0002] Aluminum alloy has the characteristics of low density and high specific strength. It is often used as a storage tank for liquid fuel, chemical reagents, etc. However, when storing highly corrosive solutions, it is necessary to coat the inner wall with a certain thickness of heavy anti-corrosion coating such as fused epoxy. The molten coating of the inner wall is a very important process, which directly affects the quality of the cured film between the heavy anti-corrosion coating and the metal substrate after coating. The quality of the cured film is an important factor affecting the service life of the heavy anti-corrosion coating.

[0003] The existing fused epoxy heavy anti-corrosion coating technology is to apply a single-component thermosetting modified epoxy powder coating on the surface to be coated on the workpiece, so that it melts and solidifies into a film, forming a heavy anti-corrosion coating with uniform thickness and smooth surface. The existing fused epoxy anti-corrosion coating coating process operation process is: often put the workpiece into an oven for preheating, take the workpiece out of the oven after preheating, prepare the fused epoxy anti-corrosion coating on the surface to be coated by an electrostatic spray gun, and finally put the coated workpiece into an oven for heating and curing to form a film.

[0004] However, for long (about 3 meters) aluminum alloy thin-walled tanks, due to their large size, if the inner wall is treated according to the existing coating process of fusion-bonded epoxy anti-corrosion coating, there will be the following problems:

[0005] (1) After the long aluminum alloy thin-walled tank is placed in an oven for preheating to a certain temperature, it is taken out of the heating oven. On the one hand, the tank cools naturally, and on the other hand, the cooling of the powder feeding and spraying air flow during the electrostatic spraying process will cause the temperature of the inner wall of the aluminum alloy thin-walled tank to drop rapidly, especially the inner wall to be sprayed far away from the initial spraying position, so that at least part of the inner wall of the tank cannot meet the requirements of high-quality film formation and efficient thickening. At the same time, the existing technology is also difficult to ensure the uniformity of coating.

[0006] (2) After coating, the long aluminum alloy thin-walled tank is transferred into the oven. Due to its large size, the transfer time is often long, which can easily lead to the failure of the curing of the fused epoxy coating, poor leveling effect and curing quality.

[0007] (3) During the coating process of aluminum alloy thin-walled tanks, the ovens and transfer equipment required for preheating and curing are large in size, have high heating costs, and require many supporting resources for transfer, resulting in high overall costs. It is not suitable for scientific research trial production or small-scale production.

[0008] (4) When using the electrostatic spraying process to prepare thick anti-corrosion coatings, due to the high-voltage electrostatic effect, breakdown sparks are easily generated, which may cause quality defects in the coating layer at the least, or even cause fires during the coating process at the worst. Summary of the invention

[0009] In view of this, the present invention aims to propose a method for coating the inner wall of a long-length aluminum alloy thin-walled tank with a fused epoxy heavy-duty anti-corrosion coating. The method aims to solve the problems existing in the prior art of coating the inner wall of a long-length aluminum alloy thin-walled tank with a fused epoxy anti-corrosion coating, such as poor coating quality caused by tank cooling, poor coating uniformity, coating quality defects and safety hazards caused by high-voltage electrostatic coating, and poor leveling effect and curing quality caused by long tank transfer time.

[0010] To achieve the above object, the technical solution of the present invention is achieved as follows:

[0011] A method for coating the inner wall of a long-length aluminum alloy thin-walled tank with a fused epoxy heavy-duty anti-corrosion coating, comprising: S1, online preheating: arranging a silicone heating belt on the outer wall of the tank so that the silicone heating belt covers and adheres to the outer wall surface of the tank; turning on the silicone heating belt to heat the tank, and keeping it warm for a first process time after reaching the temperature; S2, rotary atomization spraying: moving a spray gun in a unidirectional linear motion along the central axis of the tank, and the nozzle of the spray gun rotates with the central axis of the tank as the central axis of rotation, so as to coat the inner wall of the tank with a low-temperature curing fused epoxy heavy-duty anti-corrosion coating; S3, in-situ thermal curing: maintaining the heating state of the tank with the silicone heating belt in step S1, keeping it warm for a second process time, and completing the coating of the fused epoxy heavy-duty anti-corrosion coating on the inner wall of the tank.

[0012] Furthermore, the heating temperature of the storage tank by the silica gel heating belt in step S1 is 30°C-230°C.

[0013] Furthermore, the temperature reaching condition in step S1 is that the inner wall surface temperature of the storage tank reaches the process temperature.

[0014] Furthermore, in step S2, the spray gun performs unidirectional linear motion at a uniform speed, and the spray head rotates at a uniform speed.

[0015] The travel speed of the spray gun is 10mm / min-15mm / min, and the rotation speed of the spray head is 5r / min-10r / min.

[0016] Furthermore, the powder feeding air flow pressure of the spray gun is 0.05MPa-0.15MPa, and the powder feeding amount is 50g / min-80g / min.

[0017] Furthermore, during the rotary atomization spraying process in step S2, the silicone heating belt always keeps the storage tank in the heat preservation and heating state in step S1.

[0018] Furthermore, the method includes: before performing step S1, pre-treating the inner wall of the storage tank, wherein the pre-treatment includes at least one of micro-arc oxidation pre-treatment, sandblasting pre-treatment, and laser etching pre-treatment.

[0019] Furthermore, for the tank whose inner wall is coated with a sintered epoxy heavy-duty anti-corrosion coating, the tensile bonding strength between the sintered epoxy heavy-duty anti-corrosion coating and the aluminum alloy substrate of the inner wall of the tank is greater than 29MPa, the coating thickness is 0.9mm-1.5mm, the coating porosity is less than 0.2%, and the deposition efficiency is greater than 70%.

[0020] Compared with the prior art, the method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a sintered epoxy heavy-duty anticorrosive coating according to the present invention has the following advantages:

[0021] The method for coating the inner wall of a long-length aluminum alloy thin-walled tank with a sintered epoxy heavy-duty anti-corrosion coating described in the present invention improves the sintering quality and coating thickening efficiency of the sintered epoxy heavy-duty anti-corrosion coating and the aluminum alloy thin-walled tank, and also improves the safety of the coating process. It also greatly simplifies the inner wall coating process flow and related operations, and reduces the coating process cost.

[0022] Specifically, the present application achieves online preheating and temperature control by wrapping a silicone heating tape around the outer wall of an aluminum alloy thin-walled tank, thereby solving the problem of rapid cooling during the transfer and coating process of the aluminum alloy thin-walled tank, so that the wall of the tank is always maintained in a constant temperature range, so that the spraying condition can meet the requirements of high-quality film formation and efficient thickening; by designing a rotary atomizing spray gun, the inner wall of the tank can be evenly coated without the aluminum alloy thin-walled tank rotating or moving. Compared with the existing high-voltage electrostatic coating, it not only avoids the efficient thickening and safety problems caused by high-voltage electrostatic coating of the inner wall, but also improves the coating efficiency of the inner wall of the tank, and can fully guarantee the uniformity of spraying; high-quality film formation of the fused epoxy heavy anti-corrosion coating on the inner wall of the aluminum alloy thin-walled tank is achieved through in-situ thermal curing, which solves the problems of poor leveling effect and curing quality caused by long transfer time, and also simplifies the inner wall coating process and related operations, significantly reduces the coating process cost, and is particularly suitable for scientific research trial production or small batch production. DETAILED DESCRIPTION

[0023] The inventive concepts of the present disclosure will be described below using terms commonly used by those skilled in the art to convey the essence of their work to other persons skilled in the art. However, these inventive concepts can be embodied in many different forms and should not be considered limited to the embodiments described herein.

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0025] Compared with the existing electrostatic spraying treatment technology and coating process operation process, the coating of the fused epoxy anti-corrosion coating on the inner wall of the long-length aluminum alloy thin-walled tank is to solve the problems existing in the prior art such as poor coating quality caused by tank cooling, poor coating uniformity, coating quality defects and safety hazards caused by high-voltage electrostatic coating, and poor leveling effect and curing quality caused by long tank transfer time.

[0026] The present application proposes a method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating, comprising:

[0027] S1, online preheating: a silicone heating belt is arranged on the outer wall of the storage tank so that the silicone heating belt covers and fits the outer wall surface of the storage tank; the silicone heating belt is turned on to heat the storage tank, and after reaching the temperature, the first process time is kept warm;

[0028] Among them, although only one silicone heating belt can be used in theory, due to the different sizes of the storage tank and the silicone heating belt, multiple silicone heating belts can be set on the outer wall of the storage tank until the outer wall of the storage tank is covered by the silicone heating belt. The first process duration is a preset parameter in the process, which can be adjusted and determined according to the actual process design requirements. The first process duration of this application can be 30 minutes.

[0029] The silicone heating belt includes a temperature sensor and a temperature controller, which are used to adjust the operating state of the silicone heating belt according to the current heating temperature of the silicone heating belt, so that the silicone heating belt can provide a relatively stable and suitable heating temperature range for the storage tank. Preferably, the silicone heating belt can realize online preheating and segmented precise temperature control.

[0030] The heating temperature of the storage tank by the silica gel heating belt is 30°C-230°C. At the same time, the temperature reaching condition in step S1 is that the inner wall surface temperature of the storage tank reaches the process temperature;

[0031] Preferably, the process temperature is a preset parameter in the process, which can be adjusted and determined according to the actual process design requirements. The process temperature of the present application can be 160°C. Correspondingly, as the preferred heating state of the silicone heating belt, the heating temperature of the storage tank by the silicone heating belt can be maintained at 155°C-165°C. At the same time, in the heat preservation heating state, the silicone heating belt can also maintain this temperature range, which can not only meet the heating requirements before the storage tank reaches the temperature, but also ensure that the storage tank can be maintained near a constant target temperature after reaching the temperature, which also helps the smooth progress of the entire temperature control process without excessive temperature fluctuations.

[0032] Step S1 heats and insulates the outer wall of the tank by setting a silicone heating belt. On the one hand, it can meet the coating temperature requirements of the fused epoxy heavy anti-corrosion coating, and can also remove moisture from the tank wall to improve the thickening efficiency of the fused epoxy anti-corrosion coating. On the other hand, it completely solves the cooling problem of the tank during the transfer and coating process in the prior art, so that the wall of the tank is always maintained in a constant temperature range, so that the spraying situation can meet the requirements of high-quality film formation and efficient thickening. At the same time, in the subsequent curing process, it also helps to improve the curing quality of the fused epoxy heavy anti-corrosion coating. Correspondingly, for the insulation process after reaching the temperature, the inner wall surface temperature of the tank can be maintained at about 160°C by adjusting the operating state of the silicone heating belt.

[0033] S2, rotary atomization spraying: the spray gun is moved linearly in one direction along the central axis of the tank, and at the same time, the nozzle of the spray gun is rotated with the central axis of the tank as the central axis of rotation, so as to coat the inner wall of the tank with a low-temperature curing fusion-bonded epoxy heavy anti-corrosion coating;

[0034] Here, "one-way" means from one side to the other side along the central axis of the tank, such as from left to right, from right to left, etc.

[0035] The spray gun moves in a unidirectional linear manner at a uniform speed, and the spray head rotates at a uniform speed. Preferably, the spray gun has a travel speed of 10 mm / min-15 mm / min, and the spray head rotates at a uniform speed of 5 r / min-10 r / min. Therefore, there is no need to rotate or move the tank, but only to keep the tank stationary. The low-temperature curing fused epoxy heavy anti-corrosion coating is applied to the inner wall of the tank through the rotary atomization of the spray gun, and the uniformity of the spraying can be fully guaranteed, thereby improving the coating efficiency of the inner wall of the tank.

[0036] The powder delivery air flow pressure of the spray gun is 0.05MPa-0.15MPa, and the powder delivery amount is 50g / min-80g / min, so that the spray gun can evenly spray a sufficient amount of powder on the inner wall of the storage tank during movement and rotation to meet the requirements of final coating thickness and cured film quality.

[0037] At the same time, in step S2, by controlling the powder feeding amount, the gun travel speed and the rotation speed, efficient thickening and one-time coating of the fused epoxy heavy anti-corrosion coating on the inner wall of the tank can be achieved.

[0038] Preferably, during the rotary atomization spraying process of step S2, the silicone heating belt can keep the tank in an insulating and heating state at all times. On the one hand, it avoids cooling of the inner wall at the unsprayed position to ensure that the spraying conditions at various positions of the inner wall can meet the requirements of high-quality film formation and efficient thickening. On the other hand, for the inner wall positions that have completed spraying, due to the insulating heating of the silicone heating belt, they can directly enter the curing process immediately after spraying. Compared with the prior art, there is no transition interval between spraying and curing, which can effectively ensure the leveling effect and curing quality, improve the final coating quality, and also help to simplify the process flow and related operations, which can significantly reduce the coating process cost.

[0039] S3, in-situ heat curing: keep the heating state of the storage tank by the silicone heating belt in step S1, keep the temperature for the second process time, and complete the coating of the fused epoxy heavy anti-corrosion coating on the inner wall of the storage tank.

[0040] Among them, since steps S1 and S2 do not remove the silicone heating belt on the outer wall of the storage tank, and there is no need to move or rotate the storage tank, so that the storage tank and the silicone heating belt are kept in place, in step S3, it is only necessary to maintain the operation of the silicone heating belt in step S1, and keep it warm for the second process time after reaching the temperature, and the coating of the fused epoxy heavy anti-corrosion coating on the inner wall of the storage tank can be completed. Compared with the prior art, the present application greatly simplifies the inner wall coating process and related operations, can significantly reduce the coating process cost, and is particularly suitable for scientific research trial production or small batch production. It should be noted that the heating temperature, temperature reaching conditions, and insulation temperature of the silicone heating belt in step S3 are consistent with those in step S1 and are not repeated here.

[0041] In addition, the second process duration is a preset parameter in the process and can be adjusted and determined according to actual process design requirements. The second process duration of the present application can be 20 minutes.

[0042] After the processing process of steps S1-S3, for the tank with the inner wall coated with the sintered epoxy heavy anti-corrosion coating, the tensile bonding strength between the sintered epoxy heavy anti-corrosion coating and the aluminum alloy substrate of the inner wall of the tank is greater than 29MPa, the coating thickness is 0.9mm-1.5mm, the coating porosity is less than 0.2%, and the deposition efficiency is greater than 70%.

[0043] After step S3 is completed, the tank with the inner wall coated can be transferred to the machining section such as turning, milling, grinding, and polishing of the fused epoxy heavy anti-corrosion coating for subsequent processing.

[0044] Before performing step S1, the method pre-treats the inner wall of the tank, wherein the pre-treatment includes at least one of micro-arc oxidation pre-treatment, sandblasting pre-treatment, and laser etching pre-treatment.

[0045] Therefore, the present application provides a coating process for the sintered epoxy heavy anti-corrosion coating on the inner wall surface of a long-length aluminum alloy thin-walled tank, which improves the sintering quality and coating thickening efficiency of the sintered epoxy heavy anti-corrosion coating and the aluminum alloy thin-walled tank, and also improves the safety of the coating process, and greatly simplifies the inner wall coating process flow and related operations, reducing the coating process cost.

[0046] Specifically, the present application achieves online preheating and temperature control by wrapping a silicone heating tape around the outer wall of an aluminum alloy thin-walled tank, thereby solving the problem of rapid cooling during the transfer and coating process of the aluminum alloy thin-walled tank, so that the wall of the tank is always maintained in a constant temperature range, so that the spraying condition can meet the requirements of high-quality film formation and efficient thickening; by designing a rotary atomizing spray gun, the inner wall of the tank can be evenly coated without the aluminum alloy thin-walled tank rotating or moving. Compared with the existing high-voltage electrostatic coating, it not only avoids the efficient thickening and safety problems caused by high-voltage electrostatic coating of the inner wall, but also improves the coating efficiency of the inner wall of the tank, and can fully guarantee the uniformity of spraying; high-quality film formation of the fused epoxy heavy anti-corrosion coating on the inner wall of the aluminum alloy thin-walled tank is achieved through in-situ thermal curing, which solves the problems of poor leveling effect and curing quality caused by long transfer time, and also simplifies the inner wall coating process and related operations, significantly reduces the coating process cost, and is particularly suitable for scientific research trial production or small batch production.

[0047] The technical solution of the present application is described in detail below in conjunction with specific embodiments.

[0048] Example 1

[0049] The inner wall of the aluminum alloy thin-wall tank is pretreated by micro-arc oxidation, and then the following operations are performed:

[0050] (1) Online preheating. Use 7 pieces of silicone heating tapes with built-in temperature sensors and temperature controllers and rated power of 1kW-3kW to tightly wrap the outer wall of the aluminum alloy thin-walled tank (1 meter long sample), set the temperature of each section to 155℃-165℃, and make fine adjustments to each section based on the measured value of the inner wall surface. Control the inner wall surface temperature to 160℃, and keep it warm for 30 minutes after reaching the temperature.

[0051] (2) Rotary atomization spraying: Use a rotary atomization spray gun, adjust the powder delivery air flow pressure to 0.05MPa, the powder delivery amount is 50g / min, the spray gun moves linearly from left to right along the center axis of the tank, the gun travel speed is 10mm / min, the nozzle rotation speed is 5r / min, and the inner wall is coated with a low-temperature curing fusion-bonded epoxy heavy anti-corrosion coating.

[0052] (3) In-situ heat curing: After the inner wall of the aluminum alloy thin-wall tank is coated, the heating parameters of the online preheating stage are maintained for 20 minutes to complete the in-situ heat curing film formation.

[0053] After the above coating and curing film formation, the tensile bonding strength of the sintered epoxy heavy anti-corrosion coating and the aluminum alloy substrate pretreated by micro-arc oxidation reaches 35.4MPa, the coating thickness is 0.9mm-1.2mm, the coating porosity is less than 0.2%, and the deposition efficiency is about 76%.

[0054] Example 2

[0055] The inner wall of the aluminum alloy thin-wall tank is pre-treated by sandblasting, and then the following operations are performed:

[0056] (1) Online preheating. Use 20 pieces of silicone heating tapes with built-in temperature sensors and temperature controllers and rated power of 1-3kW to tightly wrap the outer wall of the aluminum alloy thin-walled storage tank (2.8 meters long). Set the temperature of each section to 155℃-165℃, and make fine adjustments to each section based on the actual measured value of the inner wall surface. Control the inner wall surface temperature to 160℃ and keep it warm for 30 minutes after reaching the temperature.

[0057] (2) Rotary atomization spraying: Use a rotary atomization spray gun, adjust the powder delivery air flow pressure to 0.1MPa, the powder delivery amount is 50g / min, the spray gun moves linearly from left to right along the center axis of the tank, the gun travel speed is 10mm / min, the nozzle rotation speed is 10r / min, and the inner wall is coated with a low-temperature curing fusion-bonded epoxy heavy anti-corrosion coating.

[0058] (3) In-situ heat curing: After the inner wall of the aluminum alloy thin-wall tank is coated, the heating parameters of the online preheating stage are maintained for 20 minutes to complete the in-situ heat curing film formation.

[0059] After the above coating and curing film formation, the tensile bonding strength of the sintered epoxy heavy anti-corrosion coating and the aluminum alloy substrate pretreated by sandblasting reaches 29.7MPa, the coating thickness is 1.0mm-1.3mm, the coating porosity is less than 0.2%, and the deposition efficiency is about 73%.

[0060] Example 3

[0061] The inner wall of the aluminum alloy thin-wall tank is pre-treated by laser etching, and then the following operations are performed:

[0062] (1) Online preheating. Use 22 pieces of silicone heating tapes with built-in temperature sensors and temperature controllers and rated power of 1-3kW to tightly wrap the outer wall of the aluminum alloy thin-walled storage tank tube (3.2 meters long). Set the temperature of each section to 155℃-165℃, and make fine adjustments to each section based on the actual measured value of the inner wall surface. Control the inner wall surface temperature to 160℃, and keep it warm for 30 minutes after reaching the temperature.

[0063] (2) Rotary atomization spraying: Use a rotary atomization spray gun, adjust the powder delivery air flow pressure to 0.15MPa, the powder delivery amount is 80g / min, the spray gun moves linearly from left to right along the center axis of the tank, the gun travel speed is 15mm / min, the nozzle rotation speed is 10r / min, and the inner wall is coated with a low-temperature curing fusion-bonded epoxy heavy anti-corrosion coating.

[0064] (3) In-situ heat curing: After the inner wall of the aluminum alloy thin-walled storage tank tube is coated, the online preheating parameters are maintained and kept warm for 20 minutes to complete the in-situ heat curing film formation.

[0065] After the above coating and curing film formation, the tensile bonding strength of the sintered epoxy heavy anti-corrosion coating and the aluminum alloy tube blank substrate after laser etching pretreatment reaches 46.3MPa, the coating thickness is 1.1mm-1.5mm, the coating porosity is less than 0.2%, and the deposition efficiency is about 72%.

[0066] By adopting the coating technical scheme and specific implementation process of the fused epoxy heavy anti-corrosion coating on the inner wall of the tank provided by the present invention, high-quality heavy anti-corrosion coating can be achieved on the inner wall of a long-length aluminum alloy thin-wall tank. Compared with the current electrostatic spraying treatment technology, it has the advantages of high efficiency, safety, low cost, and high quality. At the same time, the present application solves the constant temperature technical problems in the transfer, coating, and curing processes of aluminum alloy thin-wall tanks, improves the curing quality of the fused epoxy heavy anti-corrosion coating, simplifies the coating process equipment, reduces production costs, and is conducive to the linear amplification production of small batches of workpieces in the future. In addition, the present application realizes the control of the inner wall coating uniformity of the aluminum alloy thin-wall tank under non-rotating conditions through rotary atomization spraying, and also improves the inner wall coating efficiency, solving the safety problems and coating quality defects that may be caused by high-voltage electrostatic spraying of thick anti-corrosion coatings.

[0067] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for coating the inner wall of a long-length aluminum alloy thin-walled tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating, characterized in that: The method comprises: S1, online preheating: a silicone heating belt is arranged on the outer wall of the storage tank so that the silicone heating belt covers and fits the outer wall surface of the storage tank; the silicone heating belt is turned on to heat the storage tank, and after reaching the temperature, the first process time is kept warm; S2, rotary atomization spraying: the spray gun is moved linearly in one direction along the central axis of the tank, and the nozzle of the spray gun is rotated with the central axis of the tank as the central axis of rotation, so as to coat the inner wall of the tank with a low-temperature curing fusion-bonded epoxy heavy anti-corrosion coating; S3, in-situ heat curing: keep the heating state of the storage tank by the silicone heating belt in step S1, keep the temperature for the second process time, and complete the coating of the fused epoxy heavy anti-corrosion coating on the inner wall of the storage tank.

2. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: The heating temperature of the storage tank by the silica gel heating belt in step S1 is 30°C-230°C.

3. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: The temperature reaching condition in step S1 is that the inner wall surface temperature of the tank reaches the process temperature.

4. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: In step S2, the spray gun performs unidirectional linear motion at a uniform speed, and the spray head rotates at a uniform speed.

5. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 4 is characterized in that: The travel speed of the spray gun is 10mm / min-15mm / min, and the rotation speed of the spray head is 5r / min-10r / min.

6. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: The powder feeding air flow pressure of the spray gun is 0.05MPa-0.15MPa, and the powder feeding amount is 50g / min-80g / min.

7. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: During the rotary atomization spraying process in step S2, the silicone heating belt always keeps the storage tank in the heat preservation and heating state in step S1.

8. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: The method comprises: before performing step S1, pre-treating the inner wall of the tank, wherein the pre-treatment comprises at least one of micro-arc oxidation pre-treatment, sandblasting pre-treatment and laser etching pre-treatment.

9. The method for coating the inner wall of a long-length aluminum alloy thin-wall tank with a fusion-bonded epoxy heavy-duty anti-corrosion coating according to claim 1 is characterized in that: For the tank whose inner wall is coated with a sintered epoxy heavy-duty anti-corrosion coating, the tensile bonding strength between the sintered epoxy heavy-duty anti-corrosion coating and the aluminum alloy substrate of the tank inner wall is greater than 29MPa, the coating thickness is 0.9mm-1.5mm, the coating porosity is less than 0.2%, and the deposition efficiency is greater than 70%.