A method of decoking an aircraft aluminum alloy

Abstract

The application provides a method for removing accumulated carbon on an aircraft aluminum alloy, and belongs to the technical field of aviation manufacturing and maintenance. The method uses glycerol, dimethyl carbonate and polyethylene glycol as a colloidal solvent, and silicon carbide as an abrasive, and the above-mentioned components are mixed to form a polishing paste with polishing performance, which is used for polishing the accumulated carbon on the surface of the aircraft aluminum alloy, so that the carbon residues on the surface of the metal are removed, and the surface scratch of the metal is reduced. The polishing paste for removing accumulated carbon on the aircraft aluminum alloy obtained by the method is in a colloidal state, so that the paste cannot flow along the surface of the accumulated carbon during use, and the loss of the material is reduced. Meanwhile, the several chemical raw materials are non-toxic during and after preparation, and the safety of the operators and environmental pollution are not caused. In addition, the operation method is simple, the involved equipment and conditions are simple, the roughness of the surface of the metal can be ensured after operation, and the surface coating is not damaged.

Description

TECHNICAL FIELD

[0001] The present application belongs to the field of aviation manufacturing and maintenance, and relates to a method for removing carbon deposition from an aircraft aluminum alloy. BACKGROUND

[0002] During the maintenance of an aircraft, carbon deposition often occurs on the aluminum alloy at high-temperature parts in contact with air and fuel. The carbon deposition mainly consists of organic substances such as hydroxy acid, asphaltene and tar, and also contains impurities in the air. The carbon deposition has stable chemical properties and is not suitable for cleaning with a solvent. In addition, the carbon deposition cannot be in long-term contact with acidic substances attached to the metal. The carbon deposition position of the aircraft is located at the tail of the aircraft jet port, and the area to be cleaned is large. In addition, the cleaning position is a non-closed structure. Carbon deposition cleaning usually uses a steel ball or a steel wire brush to grind. This method for removing carbon deposition can easily cause deep scratches on the surface of the aluminum alloy, damage the plating layer, and the steel wire of the steel ball can easily fall off during grinding and remain in the aircraft. This largely restricts the operation difficulty of carbon deposition cleaning work. SUMMARY

[0003] In view of the above problems, the present application relates to a method for removing carbon deposition from an aircraft aluminum alloy. The method uses glycerol, dimethyl carbonate and polyethylene glycol as a colloidal solvent, and silicon carbide as an abrasive to mix into a polishing paste with polishing performance for polishing the carbon deposition position on the surface of the aircraft aluminum alloy to remove carbon residues on the metal surface and reduce scratches on the metal surface.

[0004] A method for removing carbon deposition from an aircraft aluminum alloy, comprising the following steps:

[0005] 1) Selecting silicon carbide abrasive: 240-320 mesh.

[0006] 2) First, mix glycerol and equal mass of dimethyl carbonate at a temperature of 30-45°C, and then put it into a warming box at a temperature of 60-65°C for continuous warming for 4 hours.

[0007] 3) Then, put 20g of polyethylene glycol and 35g of silicon carbide abrasive into 100ml of the solution prepared in step 2), mix and fully stir at room temperature to make the whole solution into a colloidal state, and obtain a carbon deposition removal polishing paste.

[0008] 4) Dip the carbon deposition removal polishing paste with degreasing cotton or cotton cloth material, and repeatedly polish the aluminum alloy material with carbon deposition. After the carbon deposition is cleaned, wipe it with clean degreasing cotton or cotton cloth, and finally wash it with water to clean the silicon carbide abrasive and carbon deposition at the polishing position.

[0009] The method of the present application has the following advantages: the carbon deposit grinding paste obtained by the method of the present application is in a colloidal state, so that the paste does not flow on the surface of the carbon deposit metal during use, thereby reducing the loss of material; meanwhile, the several chemical raw materials are non-toxic during and after preparation, so that the safety of the operators and the environment are not affected; the operation method is simple, the involved equipment and conditions are simple, and the roughness of the metal surface can be ensured after operation without damaging the surface coating. DETAILED DESCRIPTION

[0010] The specific embodiments of the present application will be described in detail below in combination with the technical solutions.

[0011] The present application provides a method for removing carbon deposits from an aircraft aluminum alloy, comprising the following steps:

[0012] 1) Selecting silicon carbide abrasive: 300 mesh.

[0013] 2) First, mix glycerol with an equal amount of dimethyl carbonate at a temperature of 40°C, then put it in a warming box at 63°C and continue to warm for 4 hours.

[0014] 3) Then put 20g of polyethylene glycol and 35g of silicon carbide abrasive into 100ml of the solution prepared in step 2), mix well and stir at room temperature until the whole solution becomes colloidal. The obtained colloidal and paste mixture is most stable, and no more than 20% of the silicon carbide abrasive is precipitated after long storage.

[0015] 4) Dip the carbon deposit removal grinding paste into the degreasing cotton or cotton cloth material, and repeatedly grind the aluminum alloy material with carbon deposits. After the carbon deposits are cleaned, use clean degreasing cotton or cotton cloth to wipe, and finally wash the grinding site with water to clean the silicon carbide abrasive and carbon deposits.

[0016] Example 1: Comparison of effective operation time and roughness of aluminum alloy surface after cleaning

[0017] According to the decomposition site work, the thickness of the carbon deposits on the frequently cleaned parts of the aircraft is measured, and aluminum alloy materials with carbon deposits of average thickness of 0.2mm, 0.3mm and 0.5mm are selected for comparison and statistics of carbon deposit removal by multiple operators.

[0018] Operators: 10 skilled workers with more than 5 years of repair experience are selected.

[0019] Operation object: aluminum alloy carbon deposit samples with average thickness of 0.2mm, 0.3mm and 0.5mm are selected for verification, and the area of the aluminum alloy to be cleaned is 1 / 4m 2 , and the original surface roughness of the aluminum alloy is Ra0.2.

[0020] Operating environment: select room temperature working site, indoor temperature 20-23℃, humidity 50-75%, illumination 600lx. Temperature, humidity and illumination all meet the normal aircraft decomposition working site repair requirements.

[0021] Comparative method:

[0022] 1) 10 operators are divided into 10 groups, then steel wire ball is used to clean the aluminum alloy with 0.2mm, 0.3mm and 0.5mm carbon thickness respectively, and the cleaning effect is shown in Table 1.

[0023] Table 1

[0024]

[0025] Operation result analysis: when using steel wire ball for cleaning, the gap between the steel wire winding in the steel wire ball is large, so each cleaning is not complete, and needs to be repeated several times. In addition, the steel wire in the steel wire ball is prone to metal fatigue and breakage after repeated use, which increases the cleaning time of the steel wire.

[0026] 2) According to the operating method in the application, 10 operators are asked to operate the same object sample again, and make the same inspection after decomposition, and the detailed results are shown in Table 2.

[0027] Table 2

[0028]

[0029] Operation result analysis: after using the decomposition method of the application, the operation time is significantly shortened, and the surface roughness of the metal part is good, and the change of the surface roughness of the aluminum alloy is small.

Claims

1. A method of decarbonizing an aircraft aluminum alloy, characterized by, The method comprises the following steps: 1) selecting silicon carbide abrasive; 2) first, mix glycerin and equal mass of dimethyl carbonate at 40℃, then put into a 60-65℃ warming box and continue to warm for 4 hours; 3) then, put 20g polyethylene glycol and 35g silicon carbide abrasive into 100ml of the solution prepared in step 2), mix and fully stir at room temperature, so that the whole solution becomes gel, to obtain carbon removal polishing paste; 4) dip the carbon removal polishing paste, repeatedly polish the aluminum alloy material with carbon deposition, then wipe with clean degreasing cotton or cotton cloth when the carbon deposition is cleaned, finally wash with water to clean the silicon carbide abrasive and carbon deposition at the polishing site.

2. A method of decarbonizing an aircraft aluminum alloy as defined in claim 1, wherein, The silicon carbide abrasive in step 1) is 240-320 mesh.

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