Method for alkaline oxidation treatment of the surface of an alloy steel material

Abstract

The application provides a surface alkaline oxidation treatment method of an alloy steel material, which comprises the following steps: removing the carbon layer on the surface of the alloy steel material by machining, removing the oil stains and impurities on the surface of the alloy steel material, immersing and etching the alloy steel material in an acid activation treatment solution, removing the rust on the surface of the alloy steel material, dissolving the original oxidation film on the surface of the alloy steel material, exposing the surface of the alloy steel material, performing three times of alkaline oxidation treatment on the activated alloy steel material, oxidizing the surface of the alloy steel material to form a film, performing hot water cleaning on the alloy steel material after the alkaline oxidation film formation, and controlling the drying or saponifying and then blowing dry of the alloy steel material after oil immersion. The application can improve the film formation quality and corrosion resistance, solve the red hanging ash problem and the poor adhesion problem of the metal oxidation at room temperature in the traditional metal alkaline oxidation process, improve the oxidation film formation quality and corrosion resistance, has high process operability, low cost and is easy to realize continuous production.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of metal material surface treatment, and particularly relates to an alkaline oxidation treatment method for alloy steel material surface. BACKGROUND

[0002] In the chemical oxidation treatment process of metal material, the surface color of the chemical oxidation film is related to the alloy composition of the material and the oxidation process. Generally, carbon steel and low alloy steel are black and blue-black, and alloy steel is brown to black-brown after oxidation treatment due to high silicon content, the thickness of the film layer is about 0.6-1.6 microns, and the corrosion resistance of the oxidation film is poor. The traditional part oxidation blue process adopts an alkaline process of nitrite, which is high in temperature, high in energy consumption, long in treatment time, and prone to red hanging gray, which greatly reduces the corrosion resistance. The current normal temperature oxidation process is energy-saving, fast and easy to operate, such as selenium-copper series, but has the characteristics of poor adhesion. Therefore, how to solve the problems of red hanging gray of metal oxidation film, poor adhesion and poor corrosion resistance is an urgent problem for the technical personnel in the field. SUMMARY

[0003] (I) Technical problem to be solved

[0004] The application provides an alkaline oxidation treatment method for alloy steel material surface to solve the technical problems of red hanging gray of metal oxidation film, poor adhesion and poor corrosion resistance.

[0005] (II) Technical scheme

[0006] In order to solve the above technical problems, the application provides an alkaline oxidation treatment method for alloy steel material surface, which comprises the following steps:

[0007] S1. Removing the carbon layer on the surface of the alloy steel material by machining;

[0008] S2. Removing the oil stains and impurities on the surface of the alloy steel material;

[0009] S3. Immersing and etching the alloy steel material in an acid activation treatment solution to remove rust on the surface of the alloy steel material, dissolve the original oxidation film on the surface of the alloy steel material, and expose the surface of the alloy steel material body;

[0010] S4. Carrying out three alkaline oxidation treatments on the activated alloy steel material to oxidize the surface of the alloy steel material into a film;

[0011] S5. Hot water cleaning the alloy steel material after alkaline oxidation film formation;

[0012] S6. Controlling the drying of the alloy steel material after oil immersion or blowing dry after saponification.

[0013] Further, in step S2, the surface of the alloy steel material is cleaned using a cleaning agent or a chemical degreasing method.

[0014] Further, in step S3, the PH value of the acid activation treatment solution is 5-6, and the etching time is 3-10 minutes.

[0015] Further, in step S4, the oxidizing agent used for the alkaline oxidation treatment is configured in the following proportions: NaOH: NaNO2 = (3-3.5): 1, and the amount of additive in the oxidizing agent is 5-20 g / L, and the additive is an alcohol or an ester substance.

[0016] Further, the additive is ethylene glycol, glycerol, glycerol fatty acid ester, or sodium hydroxymethyl cellulose.

[0017] Further, in step S4, when the alkaline oxidation treatment is performed three times, the alloy steel material is sequentially placed in a first oxidation tank, a second oxidation tank, and a third oxidation tank, and the first alkaline oxidation treatment, the second alkaline oxidation treatment, and the third alkaline oxidation treatment are performed respectively.

[0018] Further, in step S4, the alkaline oxidation treatment time is 10-15 minutes, and the temperature is 140-145℃.

[0019] Further, in step S4, the NaOH in the first oxidation tank is 450-600 g / L, and the NaNO2 is 150-250 g / L, and after the first alkaline oxidation treatment, the alloy steel material is immersed in an acid solution for 1-1.5 minutes to remove the oxidation film, and the acid solution used includes chromic anhydride 150-200 g / L and sulfuric acid 10-15 g / L; the NaOH in the second oxidation tank is 500-600 g / L, and the NaNO2 is 150-270 g / L; the NaOH in the third oxidation tank is 550-650 g / L, and the NaNO2 is 200-270 g / L; and the color of the solution after each alkaline oxidation treatment is beige and has no precipitate.

[0020] Further, in step S4, after the third alkaline oxidation treatment, the alloy steel material is cleaned with flowing water for 0.5-1 minute.

[0021] Further, in step S4, after the third alkaline oxidation treatment, the alloy steel material is cleaned with flowing water for 0.5-1 minute.

[0022] (Three) beneficial effects

[0023] The application provides an alloy steel material surface alkaline oxidation treatment method, which comprises the following steps: removing the carbon layer on the surface of the alloy steel material by machining, removing the oil stains and impurities on the surface of the alloy steel material, immersing the alloy steel material in an acid activation treatment solution to etch and remove the rust on the surface of the alloy steel material, dissolving the original oxidation film on the surface of the alloy steel material to expose the surface of the alloy steel material, performing three alkaline oxidation treatments on the activated alloy steel material, oxidizing the surface of the alloy steel material to form a film, cleaning the alloy steel material in hot water after the alkaline oxidation film formation, and controlling the drying or saponifying and drying of the alloy steel material after oil immersion. The carbon layer on the surface of the metal is removed by machining, the alkaline oxidation treatment is performed for multiple times, and the components of the film forming solution are optimized by adding additives, so that the film forming quality and corrosion resistance are improved, the red hanging ash problem and the poor oxidation adhesion problem of the metal at room temperature in the traditional metal alkaline oxidation process are solved, the oxidation film forming quality and corrosion resistance are improved, the process is easy to operate, the cost is low, and the continuous production is easy to realize. BRIEF DESCRIPTION OF DRAWINGS

[0024] Figure 1 The application provides an alloy steel material surface alkaline oxidation treatment method. DETAILED DESCRIPTION

[0025] In order to make the purpose, content and advantages of the application clearer, the specific embodiments of the application are further described in detail below with reference to the drawings and examples.

[0026] The application provides an alloy steel material surface alkaline oxidation treatment method, and the flowchart is shown in the figure. Figure 1 The method mainly comprises the following steps.

[0027] S1. Removing the carbon layer on the surface of the alloy steel material by machining.

[0028] The surface carbon layer treatment is added before the alkaline oxidation treatment step, so that the uneven composition of the oxidation film formed due to the existence of the carbon layer in the subsequent oxidation treatment is avoided.

[0029] S2. Cleaning the surface of the alloy steel material by using a cleaning agent or a chemical oil removal method to remove the oil stains and impurities on the surface of the alloy steel material.

[0030] S3. Immersing the alloy steel material in an acid activation treatment solution (PH is 5-6) for 3-10 minutes to perform pickling on the surface of the alloy steel material, remove the rust and other impurities on the surface of the alloy steel material, dissolve the original oxidation film on the surface of the alloy steel material, and expose the surface of the alloy steel material.

[0031] S4. The total proportion of oxidizing agent used in the three alkaline oxidation treatments is configured in the following proportion: NaOH: NaNO2 = (3-3.5):1, the amount of additive is 5-20 g / L, and the additive is an alcohol or ester substance, such as ethylene glycol, glycerol, glycerol fatty acid ester, or sodium hydroxymethyl cellulose, etc., to inhibit the formation of iron hydroxide and avoid the attachment of small particles in the oxidation tank to the surface of the alloy steel material, effectively preventing red rust; the activated alloy steel material is subjected to three alkaline oxidation treatments to oxidize the surface of the alloy steel material into a film; when the three alkaline oxidation treatments are performed, the alloy steel material is sequentially placed into a first oxidation tank, a second oxidation tank, and a third oxidation tank, and is subjected to a first alkaline oxidation treatment, a second alkaline oxidation treatment, and a third alkaline oxidation treatment, respectively, each alkaline oxidation treatment being performed for 10-15 minutes at a temperature of 140-145°C; the NaOH in the first oxidation tank is 450-600 g / L, and the NaNO2 is 150-250 g / L; after the first alkaline oxidation treatment, the alloy steel material is immersed in an acid solution for 1-1.5 minutes to remove the oxidation film, the acid solution used including chromic anhydride 150-200 g / L and sulfuric acid 10-15 g / L; the NaOH in the second oxidation tank is 500-600 g / L, and the NaNO2 is 150-270 g / L; the NaOH in the third oxidation tank is 550-650 g / L, and the NaNO2 is 200-270 g / L; the color of the solution after each alkaline oxidation treatment should be beige and free of precipitates.

[0032] When the alkaline oxidation treatment is performed, the oxidation solution remaining on the surface of the alloy steel material is rapidly concentrated during the process of the alloy steel material staying in the air after being taken out of the oxidation tank, thereby causing the dissolution of the oxidation film components and the redness of the oxidation film. To prevent this problem, the alloy steel material is subjected to a rapid water cleaning for 0.5-1 minute after the three alkaline oxidation treatments, and the rapid cleaning should ensure that the cleaning has sufficient flow rate; if the flow rate of the cleaning water is insufficient, obvious red rust will be produced; after the third alkaline oxidation treatment, the alloy steel material is subjected to a high-pressure water cleaning for 1-2 minutes to further remove the residual alkali on the surface of the alloy steel material, especially for the alloy steel material having a blind hole structure; if the residual alkali in the hole is not cleaned by the high-pressure water cleaning, red rust is easily produced.

[0033] S5. The alloy steel material after the alkaline oxidation film formation is subjected to a hot water cleaning.

[0034] S6. The alloy steel material is subjected to an oil immersion and controlled drying or a saponification and drying.

[0035] S7. The film layer performance test is performed: after the alloy steel material surface is wiped, 1-2 drops of 3% copper sulfate solution is dropped, and no color change occurs within 1 minute, so it can be seen that the oxidation treatment result exceeds the 30-second requirement specified in GB665; after the alloy steel material surface is wiped, 1 drop of 0.175% sulfuric acid solution (GB625) is dropped, and the bottom is not exposed after 30 seconds, which also meets the requirement.

[0036] As can be seen from the above description, the basic oxidation treatment method can solve the problem of red rust on the surface of the alloy steel material and the problem of poor oxidation adhesion of the metal at room temperature, has the characteristics of good film forming quality, strong corrosion resistance, good stability, strong process operability, low cost and the like, and can meet the requirements of the surface technology and storage index of the alloy steel material.

[0037] The above description is only the preferred embodiment of the present application, and it should be pointed out that for ordinary skilled in the art, without departing from the technical principles of the present application, a number of improvements and modifications can be made, and these improvements and modifications should be considered as the protection scope of the present application.

Claims

1. A method for alkaline oxidation treatment of the surface of an alloy steel material, characterized by, The alkaline oxidation treatment method comprises the following steps: S1. Removing the carbon layer on the surface of the alloy steel material by machining; S2. Removing the oil stains and impurities on the surface of the alloy steel material; S3. Placing the alloy steel material into an acid activation treatment solution for etching, removing the rust on the surface of the alloy steel material, dissolving the original oxide film on the surface of the alloy steel material, and exposing the surface of the body of the alloy steel material; S4. Performing three alkaline oxidation treatments on the activated alloy steel material to oxidize a film on the surface of the alloy steel material; wherein the total proportion of the oxidizing agent used in the alkaline oxidation treatment is configured in the following proportion: NaOH:NaNO2=(3~3.5):1, the amount of the additive in the oxidizing agent is 5~20g / L, and the additive is ethylene glycol, glycerol, glycerol fatty acid ester, or sodium hydroxymethyl cellulose; when performing the three alkaline oxidation treatments, the alloy steel material is sequentially placed into a first oxidation tank, a second oxidation tank, and a third oxidation tank to perform a first alkaline oxidation treatment, a second alkaline oxidation treatment, and a third alkaline oxidation treatment, respectively; the time for each alkaline oxidation treatment is 10~15 minutes, and the temperature is 140~145℃; the concentration of NaOH in the first oxidation tank is 450g / L, and the concentration of NaNO2 is 150~250g / L; the alloy steel material is immersed in an acid solution for 1~1.5 minutes after the first alkaline oxidation treatment to remove the oxide film, and the acid solution comprises chromic anhydride 150~200g / L and sulfuric acid 10~15g / L; the concentration of NaOH in the second oxidation tank is 600g / L, and the concentration of NaNO2 is 150~270g / L; the concentration of NaOH in the third oxidation tank is 650g / L, and the concentration of NaNO2 is 200~270g / L; the solution after each alkaline oxidation treatment is milky yellow and has no precipitate; the alloy steel material is cleaned with flowing water for 0.5~1 minute after the three alkaline oxidation treatments; and the alloy steel material is further cleaned with high-pressure water for 1~2 minutes after the third alkaline oxidation treatment and the rinsing with flowing water to remove the residual alkali on the surface of the alloy steel material; S5. Hot water cleaning the alloy steel material after the alkaline oxidation film formation; S6. Oil immersion and control drying or saponification and blow drying the alloy steel material.

2. The alkaline oxidation treatment method according to claim 1, wherein In step S2, the surface of the alloy steel material is cleaned using a chemical oil removal method.

3. The alkaline oxidation treatment method according to claim 1, wherein In step S3, the pH value of the acid activation treatment solution is 5~6, and the etching time is 3~10 minutes.

Images