WO2016106525A1 - Process for film for aluminum tube drawing and application of said process - Google Patents

Abstract

A process for a film for aluminum tube drawing, and an application of said process, said process comprising the following steps: using an alkaline powder to degrease and to deburr, rinsing with water; desmutting, rinsing with water, then using a zinc system film forming agent to treat the surface of an aluminum material so as to form a film thereon, rinsing with water, drying, and using a saponification agent to carry out saponification. The zinc system film forming agent comprises the following ingredients present in the following weight percentages: 1-3% sodium fluorosilicate, 0.1-0.3% zinc fluoride, 0.05-0.10% sodium fluoride, and the remainder being water. In the process for a film for aluminum tube drawing, first an alkaline powder is used to degrease and to deburr, then, following desmutting treatment, a zinc system film forming agent is used to form a film, and then saponification and lubrication are performed. This way, the surface of a tube to be treated is better adapted to drawing. The tube may be stretched six to eight times, stretching elongation exceeding 80%. The invention allows for a high stretch rate. After the stretching process, the surface of the aluminum tube is radiant and void of cracks. The invention provides for excellent stretching results.

Description

 Aluminum tube film process and its application Technical field

 The invention relates to the technical field of metal surface treatment, in particular to an aluminum tube film process and application thereof.

Background technique

The application of aluminum pipe is more and more extensive, and the production of aluminum pipe becomes very important. The traditional aluminum pipe production usually adopts a rough aluminum pipe and then performs fine processing, such as pipe drawing, mainly by pulling the aluminum pipe blank. Cold drawing process to pump a tube with a large diameter into a small diameter pipe.

Aluminum pipe is usually treated with a processing aid such as a lubricant, otherwise the pipe may be prone to cracks and unevenness of the pipe. The existing aluminum pipe pretreatment process is: directly spraying talcum powder or applying lubricating oil to the workpiece for lubrication, and stretching, the disadvantage is that the lubrication effect is not ideal, and the parts of the workpiece are not uniformly stressed during stretching. Stretch one or two times, the length of the stretch does not exceed 20% and easy to break.

technical problem

 In view of this, an aluminum tube film process and its application which are resistant to stretching, high elongation and good effect are provided.

Technical solution

An aluminum tube coating process for pretreatment before drawing aluminum, comprising the steps of: removing oil powder, burr, washing with alkali; light treatment, water washing, and treating aluminum surface with zinc film forming agent Forming a film, washing with water, drying, and saponifying with a saponifying agent comprising the following components in a mass ratio: 1-3% sodium fluorosilicate, 0.1-0.3% zinc fluoride, 0.05-0.10% sodium fluoride and the balance water.

 And, the above aluminum tube film process is applied in an aluminum drawing tube.

Beneficial effect

The aluminum pipe coating process first uses alkali to remove oil powder, burr, and light treatment, and then forms a film with a zinc film forming agent, and then saponifies and lubricates, so that the surface of the pipe to be piped is more suitable for drawing, and the number of stretching can reach 6- 8 times, the stretch length is exceeded 80%, high tensile rate, the surface of the extruded aluminum tube is bright, no crack, and the stretching effect is excellent.

Embodiments of the invention

 The invention will now be described in detail in connection with specific embodiments.

 Embodiments of the present invention provide an aluminum tube film process for pretreatment before drawing aluminum, which includes the following steps:

 Step S01: removing the oil powder, burrs with alkali, and washing with water;

 Step S02: light treatment, water washing;

 Step S03: treating the surface of the aluminum material with a zinc-based film forming agent to form a film, washing with water, and drying;

 Step S04: Saponification is carried out using a saponifying agent.

In step S01, the base is a caustic alkali, that is, 96% sodium hydroxide, preferably a sodium hydroxide solution having a mass concentration of 4-8%. In the process of degreasing, the control alkalinity ranges from 80 to 200 pt, 1 pt=0.01. Mol/L of OH ^- . Step S01 uses strong alkaline (ie, caustic soda) degreasing powder. The reason why the strong alkaline degreasing powder is used instead of the common acidic degreasing is because the aluminum alloy has a lot of oil stains and burrs in the initial stage of processing, and the acid degreasing is not It is clean and can't get burrs, so the invention uses strong alkaline degreasing. The alkali degreasing powder has a treatment time of 5-10 minutes and a temperature of 40-80 °C.

 In step S02, the light-emitting treatment is to soak or spray the aluminum material with a light-emitting agent, and the light-emitting agent includes the following components according to the mass ratio: 8-15% nitric acid, 2-4% sulfuric acid and the balance water. The black ash generated during degreasing can be effectively removed by the light-emitting treatment process, and the cleanliness is 99.9%. In addition, the surface of the aluminum alloy can be adjusted to be flat, which effectively ensures the saponification rate and film formation firmness of the subsequent saponification. After the light is washed, it can be washed with hot water. It can ensure that the aluminum material is cleaned more cleanly and dried more quickly. It avoids some high-demand aluminum materials that are not reoxidized in time due to drying. Through the light-emitting treatment, the dust on the surface of the material can be quickly removed, the workpiece can be restored to the original color, and the adhesion of the film can be improved.

The light-emitting agent preferably comprises the following components in a mass ratio: 8-10% nitric acid, 2-3% sulfuric acid, 1-2% hydrochloric acid and the balance water. The content of nitric acid raw material is 68%, the content of sulfuric acid raw material is 98%, and the content of hydrochloric acid raw material is 33%. The light treatment time is 30-60 seconds, the total acidity of the light-emitting agent is controlled in the range of 50-200 pt, and 1 pt=0.01 mol/L of H ⁺ . When the light is emitted, the treatment time with the light-emitting agent is preferably 0.5 to 2 minutes, more preferably 1-2 minutes, and the spray treatment time is preferably 0.5 to 1 minute.

 In step S03, the zinc-based film-forming agent comprises the following components in a mass ratio: 1-3% sodium fluorosilicate, 0.1-0.3% Zinc fluoride, 0.05-0.10% sodium fluoride and the balance of water. Preferably, the zinc-based film-forming agent comprises the following components in a mass ratio: 1.5-1.8% sodium fluorosilicate, 0.15-0.18% Zinc fluoride, 0.05-0.08% sodium fluoride and the balance of water. Film formation with a zinc-based film former is to soak the aluminum for 2-4 minutes at a temperature of 80-100 ° C and a total acidity of 20-55 pt. . The film former forms a film thickness of from 3 to 10 microns.

The zinc-based film is mainly used for lubrication, and cooperates with the saponifier to improve the lubrication effect during drawing. The invention adopts a zinc-based film-forming agent, has a fine structure and firm adhesion, and can form a deep blue film with good lubricity on the surface of the aluminum alloy, and can exhibit excellent functions in pipe drawing, spinning, cold forging and the like. .

 In step S04, the saponification is used to improve the lubricity and firmness of the surface of the aluminum material so that the pipe is stretched a plurality of times without breaking. Saponifiers include zinc stearate 6-8%, sodium steate 2-4% and the balance of water. The saponifier is preferably treated by soaking the aluminum material treated in step S03 for 2-5 minutes at a temperature of 60-80 ° C, PH The value is 8-11.

 Preferably, the drying is natural drying or drying, and the drying temperature is lower than 80 °C. Industrial water can be used for washing, PH The value is about 6-7, and it is washed for 1-2 minutes at normal temperature.

 The present invention also provides the use of the above process, that is, the aluminum tube is drawn by the aluminum tube coating process as described above to form a thinner tube.

 The process flow of the aluminum tube film of the embodiment of the present invention will be described below by way of specific examples.

 Examples 1 to 3 and Comparative Examples 4 to 6

 1) Pretreatment: The aluminum tube blank to be treated is degreased and burred with a 7% alkali alkali solution, and washed with industrial tap water 1-2 Times.

 2) Prepare the light agent according to the mass ratio of Table 1. Soak the aluminum tube treated in the previous step in the light-emitting agent, soak it at room temperature. In minutes, clean with industrial tap water 1-2 times to completely remove the black ash on the surface of the aluminum tube.

 3) Prepare a zinc-based film-forming agent according to the mass ratio of Table 1, and use the zinc-based film-forming agent to soak the aluminum material at 80 °C. 4 The acidity of the zinc-based film former was 20 pt, washed with water and dried.

 4) According to the mass ratio of Table 1, the saponification agent is prepared, and the pH value of the saponifier is controlled to be 8 and will go through step 3. The treated aluminum tube is immersed in a saponification agent at 80 ° C for 4 minutes, and the saponified aluminum tube is subjected to a tensile test.

 Aluminum tube tensile test:

The aluminum material treated by the above various examples was subjected to a tensile test using a special tube puller to test the elongation of stretch, and the appearance of the aluminum tube after stretching was observed, and the brightness of the outside surface was determined. As can be seen from the test results of Table 1, Examples 1-3 A zinc-based film former and a saponifier were used, and the elongation of the aluminum tube was more than 80%, while the comparative example 4 did not use a zinc-based film-forming agent, and the elongation of the aluminum tube was low, and the comparative example was 5-6. Although a zinc-based film-forming agent is used, the content of each component is high, and an excessively high content dissolves the film formed as it is, which is disadvantageous for film formation, and the zinc-based film-forming agent does not actually function as an application.

 Table 1 Mass ratio and test results of each reagent in each example

Reagent	Serial number	Example 1	Example 2	Example 3	Comparative example 4	Comparative example 5	Comparative example 6
Alkali	Sodium hydroxide (%)	8	10	12	11	6	15
Zinc film former	Sodium fluorosilicate	1.2	1.5	1.8	0	2.5	3.2
	Zinc fluoride (%)	0.12	0.15	0.18	0	0.25	0.3
	Sodium fluoride (%)	0.06	0.08	0.10	0	0.12	0.15
	Water (%)	98.62	98.27	97.92	0	97.13	96.55
Light agent	Nitric acid (%)	15	12	9	6	16	18
	Sulfuric acid (%)	2	3	4	9	1	2
	Water (%)	83	85	87	85	83	80
Saponifier	Zinc stearate (%)	6	7	8	6	9	10
	Sodium stearate (%)	4	3	2	4	1	0
	Water (%)	90	90	90	90	90	90
Tensile test	Extension rate (%)	81	82	85	25	45	55

It should be noted that the present invention is not limited to the above embodiments, and other changes may be made by those skilled in the art according to the inventive spirit of the present invention, and the changes according to the inventive spirit of the present invention should be included in the present invention. Within the scope of the claimed invention.

Claims (10)

1. An aluminum tube coating process for pretreatment before drawing aluminum, comprising the steps of: removing oil powder, burr, washing with alkali; light treatment, water washing, and treating aluminum surface with zinc film forming agent Forming a film, washing with water, drying, and saponifying with a saponifying agent comprising the following components in a mass ratio: 1-3% sodium fluorosilicate, 0.1-0.3% zinc fluoride, 0.05-0.10% sodium fluoride and the balance water.
2. The aluminum tube coating process according to claim 1, wherein the saponifying agent comprises the following components in a mass ratio: zinc stearate 6-8%, sodium stearate 2-4% and the balance of water.
3. The aluminum tube coating process according to claim 1, wherein the base is a sodium hydroxide solution having a concentration of 4-8% by mass.
4. Claims 3 The aluminum tube coating process is characterized in that the light-emitting treatment is to soak or spray aluminum material with a light-emitting agent, and the light-emitting agent comprises the following components of mass ratio: 8-15% nitric acid, 2 -4% Sulfuric acid and the balance of water.
5. The aluminum tube filming process according to claim 1, wherein the alkalinity is controlled to have an alkalinity ranging from 30 to 100 pt.
6. The aluminum tube filming process according to claim 1, wherein the zinc-based film-forming agent comprises the following components in a mass ratio: 1.5-1.8% Sodium fluorosilicate, 0.15-0.18% zinc fluoride, 0.05-0.08% sodium fluoride and the balance water.
7. The aluminum tube coating process according to claim 6, wherein the film has a film thickness of from 3 to 10 μm.
8. The aluminum tube coating process according to claim 1, wherein the film forming step is: treating the aluminum surface with a zinc-based film former at a temperature of 80 to 100 ° C. 2-4 minutes.
9. The aluminum tube coating process according to claim 1, wherein the saponification process is: using a saponifying agent at a pH of 8-11, 60-80 Soak for 2-5 minutes at °C.
10. The use of the aluminum tube coating process according to any one of claims 1 to 9 in an aluminum drawing tube.