阅读说明：本技术 一种铝合金管材清洗剂及工艺方法 (Aluminum alloy pipe cleaning agent and process method ) 是由 杜娟 朱凯 文庆杰 谭瑶 李剑飞 王大为 虞文军 于 2020-04-23 设计创作，主要内容包括：本发明属于铝合金表面处理技术领域,涉及一种铝合金管材清洗剂及工艺方法,清洗剂成分为1～2g/L碳酸钠和1～2g/L偏硅酸钠；步骤为：装夹、乳化清洗、温水洗、冷水洗、酸洗、冷水洗、非侵蚀型碱清洗、温水洗、冷水洗、检查、脱氧、冷水洗、干燥。本发明的铝合金管材清洗剂,成分简单,不含有害物质,环保高效；本发明的铝合金管材清洗方法,有效解决了铝合金清洗后的白斑问题,提高了管材的内外表面质量,具有可批量操作、清洗效率高；清洗剂含量相比传统配方低,低残留,易清洗。(The invention belongs to the technical field of aluminum alloy surface treatment, and relates to an aluminum alloy pipe cleaning agent and a process method, wherein the components of the cleaning agent are 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate; the method comprises the following steps: clamping, emulsifying cleaning, warm water cleaning, cold water cleaning, acid cleaning, cold water cleaning, non-erosion type alkali cleaning, warm water cleaning, cold water cleaning, checking, deoxidizing, cold water cleaning and drying. The aluminum alloy pipe cleaning agent disclosed by the invention is simple in components, free of harmful substances, environment-friendly and efficient; the method for cleaning the aluminum alloy pipe effectively solves the problem of white spots after the aluminum alloy is cleaned, improves the quality of the inner surface and the outer surface of the pipe, and has the advantages of batch operation and high cleaning efficiency; compared with the traditional formula, the content of the cleaning agent is low, the residue is low, and the cleaning is easy.)

1. The aluminum alloy pipe cleaning agent is characterized by comprising 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate.

2. The cleaning process method of the aluminum alloy pipe is characterized by comprising the following steps:

a) clamping: clamping an aluminum alloy pipe on a tool, so that the pipe is perpendicular to the liquid level as much as possible, and high cleaning efficiency and uniformity are ensured;

b) emulsification and oil removal: soaking the pipe in an emulsion tank at 50-75 ℃ for 2-3 min, wherein emulsion cleaning liquid is Turco 6849 aqueous solution, the concentration is 10-20%, and stirring;

c) warm water washing: soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min;

d) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

e) acid washing: soaking the pipe in a 70% nitric acid solution at room temperature for 2-3 min;

f) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

g) non-erosion type alkali cleaning: soaking the pipe in a non-erosion type alkali cleaning solution at the temperature of 60-70 ℃ for 2-3 min, wherein the components of the pipe are 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate, and stirring;

h) warm water washing: soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min;

i) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

j) and (4) checking: checking that the inner surface and the outer surface of the pipe reach a water film non-breaking state, and repeating the steps g) to i if the inner surface and the outer surface of the pipe do not meet the water film non-breaking state);

k) and (3) deoxidation: immersing the pipe into a deoxidizing tank at room temperature, wherein the components of a deoxidizing solution comprise 10-15% of nitric acid, 40-60 g/L of chromic anhydride and 1-2% of hydrofluoric acid, the deoxidizing time is 10-15 min, and stirring;

l) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

m) drying: and (5) drying or blow-drying.

3. The method for cleaning the aluminum alloy pipe according to claim 2, wherein the inner and outer surfaces of the aluminum alloy pipe cannot be dried in the middle circulation process of each step.

4. The aluminum alloy pipe cleaning process method as claimed in claim 2, wherein in the drying step, drying is carried out in a hot circulating air box with the temperature not higher than 71 ℃.

Technical Field

The invention belongs to the technical field of aluminum alloy surface treatment, and particularly relates to a cleaning process of an aluminum alloy pipe.

Background

The aluminum alloy pipe has the characteristics of low density, high strength, excellent plasticity and the like, and is widely applied as a pipeline system in the fields of aviation, aerospace, automobiles, electrical appliances and the like. Aluminum alloy raw material pipes are usually subjected to extrusion, rolling and/or drawing processes in the production process, lubricating oil or lubricating grease is often required to be coated to ensure that the aluminum pipes are smoothly formed, and dense black oil fouling films are easily formed on the inner and outer surfaces of the aluminum pipes. Because the length of the aluminum tube serving as the raw material is long, the black oil stain film on the inner surface is difficult to clean, and then when intermediate heat treatment and finished product heat treatment are carried out, oil stains are carbonized at high temperature and remain on the inner surface, and a layer of uneven oxide is formed, so that the aluminum alloy tube has many defects in the subsequent use process. Therefore, the problem of cleaning the surface (especially the inner surface) of the aluminum alloy pipe is one of the key problems restricting the use of the product.

In the prior art, in a method for removing stains on the surface of an aluminum pipe by adopting processes such as alkali corrosion (sometimes called alkali washing, namely sodium hydroxide aqueous solutions with different concentrations), hot water soaking, bright dipping and the like, although a clean matte surface can be formed after the sodium hydroxide solution is cleaned, for the condition that stubborn stains and uneven oxides exist on the surface of a raw material, the surface of the aluminum alloy pipe can be unevenly corroded due to the fact that the corrosion rate of the aluminum alloy in the sodium hydroxide solution is too high, and particularly uneven white spots are often formed on the inner surface. Experimental research shows that white spots on the surface of the aluminum pipe, which are caused by the existing cleaning process, are not white substances which are not cleaned and removed or newly generated, but are generated in a white spot region, the corrosion depth and the roughness of the white spot region are larger than those of a normal region, so that the problems of different light reflection amounts and color difference are caused. On one hand, the existing cleaning process is utilized to repeatedly clean and can not remove white spots, and even if the white spots can be removed, the size and the wall thickness of the aluminum pipe are also ultra-poor; on the other hand, due to the fact that the corrosion depth of the white spot region is large, when the aluminum pipe is used as a pipeline system, the potential safety hazard of sudden fatigue cracking from a micro-region at the white spot exists, and a subsequently formed passivation film is not uniform, so that the surface quality and the service performance of the aluminum pipe are affected.

In order to solve the white spot problem of the aluminum alloy pipe, a cleaning method which can remove stains and uneven oxides on the inner and outer surfaces of the aluminum alloy pipe and simultaneously can not selectively corrode the surface of the aluminum alloy is very necessary.

Disclosure of Invention

The purpose of the invention is as follows: the method for cleaning the aluminum alloy pipe is provided, so that the problem of white spots formed after the aluminum alloy pipe is cleaned is solved, and the quality of the inner surface and the outer surface of the aluminum alloy pipe is improved.

The technical scheme of the invention is as follows:

the aluminum alloy pipe cleaning agent is characterized by comprising 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate.

The invention discloses a cleaning process method of an aluminum alloy pipe, which is characterized by comprising the following steps of:

a) clamping: clamping an aluminum alloy pipe on a tool, so that the pipe is perpendicular to the liquid level as much as possible, and high cleaning efficiency and uniformity are ensured;

b) emulsification and oil removal: soaking the pipe in an emulsion tank at 50-75 ℃ for 2-3 min, wherein emulsion cleaning liquid is Turco 6849 aqueous solution, the concentration is 10-20%, and stirring;

c) warm water washing: soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min;

d) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

e) acid washing: soaking the pipe in a 70% nitric acid solution at room temperature for 2-3 min;

f) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

g) non-erosion type alkali cleaning: soaking the pipe in a non-erosion type alkali cleaning solution at the temperature of 60-70 ℃ for 2-3 min, wherein the components of the pipe are 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate, and stirring;

h) warm water washing: soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min;

i) and (3) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

j) and (4) checking: checking that the inner surface and the outer surface of the pipe reach a water film non-breaking state, and repeating the steps g) to i if the inner surface and the outer surface of the pipe do not meet the water film non-breaking state);

k) and (3) deoxidation: immersing the pipe into a deoxidizing tank at room temperature, wherein the components of a deoxidizing solution comprise 10-15% of nitric acid, 40-60 g/L of chromic anhydride and 1-2% of hydrofluoric acid, the deoxidizing time is 10-15 min, and stirring;

l) cold water washing: immersing the pipe in flowing water at room temperature for thoroughly cleaning for 2-3 min;

m) drying: and (5) drying or blow-drying.

In the middle circulation process of each step, the inner surface and the outer surface of the aluminum alloy pipe cannot be dried.

And in the drying step, drying is carried out in a hot circulating air box with the temperature not higher than 71 ℃.

The aluminum alloy pipe cleaning agent disclosed by the invention is simple in components, free of harmful substances, environment-friendly and efficient; the method for cleaning the aluminum alloy pipe effectively solves the problem of white spots after the aluminum alloy is cleaned, improves the quality of the inner surface and the outer surface of the pipe, and has the advantages of batch operation and high cleaning efficiency; compared with the traditional formula, the content of the cleaning agent is low, the residue is low, and the cleaning is easy.

Drawings

FIG. 1 is a flow chart of the cleaning process of the present invention.

FIG. 2 is a graph showing the effect of cleaning the same batch of 5A02 aluminum tubes by comparing the prior alkali-containing etching cleaning process with the method of the present invention.

FIG. 3 is a graph showing the cleaning effect on the same batch of aluminum tubes in comparison with different cleaning processes.

FIG. 4 is a graph showing the cleaning effect of the alkali-containing etching cleaning process and the cleaning process of the present invention on the same batch of 6061 aluminum tubes.

Detailed Description

The invention will be further illustrated with reference to the accompanying figure 1 and examples:

example one

When a batch of phi 60X 1 5A02 aluminum alloy pipes are cleaned by the existing cleaning process, no acid cleaning is carried out before alkali cleaning, alkali corrosion is carried out on the pipes by sodium hydroxide aqueous solution after alkali cleaning, and serious white spots appear on the inner surfaces of the pipes after cleaning, as shown in figure 2 a. Experimental research shows that white spots on the surface of the aluminum alloy pipe are not white substances generated by uncleaned removal of pollutants or chemical reaction, but are generated by different light reflection amounts and color difference due to the fact that the corrosion depth and the roughness of the white spot are larger than those of a normal area.

By adopting a new cleaning process, the method comprises the following steps:

a) clamping: the aluminum alloy pipe is clamped on the tool, so that the pipe is perpendicular to the liquid level as much as possible, the inner surface and the outer surface of the aluminum alloy pipe can be fully contacted with the cleaning liquid, gas generated by chemical reaction is easy to escape, selective over-corrosion caused by high local ion concentration is avoided, and the high efficiency and uniformity of cleaning are ensured.

b) Emulsification and oil removal: soaking the pipe in an emulsion tank at 50-75 ℃ for 2-3 min, wherein emulsion cleaning liquid is Turco 6849 aqueous solution with the concentration of 10-20%, stirring the emulsion cleaning liquid in the tank liquid by using compressed air, and removing heavy oil of an oil seal.

c) Warm water washing: and (3) soaking the pipe into warm water of 40-60 ℃ for thoroughly cleaning for 2-3 min, wherein the warm water can effectively clean and remove the residual emulsion cleaning liquid on the inner surface and the outer surface of the pipe.

d) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

e) Acid washing: the pipe is immersed in 70% nitric acid solution at room temperature for 2-3 min, an acid washing procedure is added before alkali cleaning, some local corrosion products formed on the surface during storage can be removed, and white spots formed by domination after subsequent alkali cleaning are avoided.

f) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

g) Non-erosion type alkali cleaning: the method comprises the steps of immersing a pipe in a 60-70 ℃ non-erosion type alkali cleaning solution for 3min, wherein the components of the alkali cleaning solution are 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate, and stirring the sodium carbonate and the sodium metasilicate in tank liquid by using compressed air, wherein the step is used for further removing oil and grease on the surface of the aluminum alloy pipe.

h) Warm water washing: and (3) immersing the pipe into warm water at 40-60 ℃ for thoroughly cleaning for 2-3 min, wherein the warm water can effectively clean and remove the alkali cleaning liquid remained on the inner surface and the outer surface of the pipe.

i) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

j) And (4) checking: and (3) checking whether the inner surface and the outer surface of the pipe reach a water film non-breaking state, wherein the step is mainly to check whether oil and grease on the inner surface and the outer surface of the pipe are completely removed.

k) And (3) deoxidation: immersing the pipe into a deoxidation tank at room temperature, wherein the components of a deoxidation solution comprise 10-15% of nitric acid, 40-60 g/L of chromic anhydride and 1-2% of hydrofluoric acid, the deoxidation time is 10min, and stirring the pipe in the tank liquid by using compressed air. The oxide on the surface of the aluminum alloy can not be uniformly removed by non-erosion type alkali cleaning, and compared with the existing alkali corrosion (sodium hydroxide aqueous solution) process, the oxide and stubborn stains on the surface of the aluminum alloy raw material pipe have slower corrosion rate in the deoxidation process, and can not cause selective over-corrosion.

l) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

m) drying: the pipe is vertically hung in a thermal cycle air box with the temperature not higher than 71 ℃, so that residual liquid drops on the surface can flow and the pipe is dried.

In the flowing process of each intermediate step, the inner surface and the outer surface of the aluminum alloy pipe cannot be dried, and the selective corrosion of the residual acid and alkali cleaning solution on the surface of the aluminum pipe in the drying process is mainly avoided. After the above washing step is finished, the inner and outer surfaces of the aluminum alloy pipe are clean without white spots, as shown in FIG. 2 b. In FIG. 2, (a) a phi 60X 1 aluminum tube 5A02 tube used in the prior alkaline-based etching cleaning process, and (b) the same batch of aluminum tubes used in the cleaning process of the present invention.

The following 3 different cleaning process step combinations are compared: clamping, emulsifying and deoiling, warm water washing, cold water washing, alkali washing, warm water washing, cold water washing, checking, deoxidizing, cold water washing and drying, wherein white spots can still be seen on the surface of the pipe after the same batch of pipes are washed; clamping, emulsifying and deoiling, warm water washing, cold water washing, acid washing, cold water washing, alkali washing, warm water washing, cold water washing, inspection, alkali corrosion, cold water washing and drying, wherein white spots can still be seen on the surface of the same batch of pipes after the pipes are washed; clamping, emulsifying and deoiling, warm water washing, cold water washing, acid washing, cold water washing, alkali washing, warm water washing, cold water washing, inspection, deoxidation, cold water washing, alkali corrosion, cold water washing and drying. After the above 3 prior art processes, white spots are still visible on the surface of the same batch of pipes after cleaning, as shown in fig. 3 a-c; the cleaning process disclosed by the invention is shown in figure 3d, and the aluminum alloy pipe cleaning process disclosed by the invention has a good cleaning effect, can effectively avoid white spots and improves the surface quality of the aluminum pipe. In fig. 3, the pipe processing corresponds to (a) a cleaning process (a), (b) a cleaning process (c), (d) a cleaning process of the present invention, respectively.

Example two

The feasibility of the cleaning process method provided by the invention is further verified by selecting a phi 16X 1 6061 aluminum alloy pipe, and the steps are as follows:

a) clamping: the aluminum alloy pipe is clamped on the tool, so that the pipe is perpendicular to the liquid level as much as possible, and the high efficiency and uniformity of cleaning are guaranteed.

b) Emulsification and oil removal: soaking the pipe in an emulsion tank at 50-75 ℃ for 2-3 min, wherein the emulsion cleaning solution is Turco 6849 aqueous solution, the concentration is 10-20%, and the tank solution is stirred by compressed air.

c) Warm water washing: and soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min.

d) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

e) Acid washing: and (3) soaking the pipe in a 70% nitric acid solution at room temperature for 2-3 min to remove corrosion points on the surface of the pipe during inventory.

f) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

g) Non-erosion type alkali cleaning: the pipe is soaked in a non-erosion type alkali cleaning solution at the temperature of 60-70 ℃ for 3min, the components of the pipe are 1-2 g/L sodium carbonate and 1-2 g/L sodium metasilicate, and the pipe is stirred in tank liquid by using compressed air.

h) Warm water washing: and soaking the pipe in warm water at 40-60 ℃ to thoroughly clean for 2-3 min.

i) And (3) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

j) And (4) checking: and checking that the inner surface and the outer surface of the pipe reach a water film non-breaking state.

k) And (3) deoxidation: immersing the pipe into a deoxidation tank at room temperature, wherein the components of a deoxidation solution comprise 10-15% of nitric acid, 40-60 g/L of chromic anhydride and 1-2% of hydrofluoric acid, the deoxidation time is 15min, and stirring the pipe in the tank liquid by using compressed air.

l) cold water washing: and (3) immersing the pipe into flowing water at room temperature to thoroughly clean for 2-3 min.

m) drying: drying with dry and clean compressed air.

During the flow process of the aluminum alloy pipe in each intermediate step, the inner and outer surfaces cannot be dried. And after the cleaning step is finished, the inner surface and the outer surface of the aluminum alloy pipe are clean and have no white spots. Referring to FIG. 4, FIG. 4 (a) shows a severe white spot in a phi 16X 1 6061 aluminum tube using an alkaline etching cleaning process; FIG. 4 (b) is a view showing the same batch of aluminum pipes cleaned without white spots by the cleaning process of the present invention.

The present invention has been described above by way of example, but the present invention is not limited to the above-described specific embodiments, and any modification or variation made based on the present invention is within the scope of the present invention as claimed.