Strip steel surface bluing process adopting electroplating method

Abstract

The invention relates to a strip steel surface bluing process adopting an electroplating method. The strip steel surface bluing process comprises the following specific steps: (1) cleaning and activating degreased and pickled strip steel; (2) injecting an electroplating solution into the electroplating bath, wherein the electroplating solution adopts a sodium hydroxide solution with the mass concentration of 5%-10%; (3) adjusting the temperature of the electroplating solution to 50-80 DEG C; (4) current is introduced into the electroplating liquid, and the current power is 16-18 KVA; (5) generating an oxidation film on the surface of the strip steel after the strip steel passes through the electroplating liquid in the electroplating bath; and (6) rinsing and drying the steel strip after the steel strip leaves the electroplating bath. The electroplating equipment is used for enabling the surface of the strip steel to be subjected to bluing reaction by electrolyzing the sodium hydroxide solution, a compact oxidation film is formed on the surface of the strip steel, normal-temperature bluing treatment of the strip steel is achieved, and the production efficiency of the strip steel is improved.

Description

Technical Field

[0001] The invention relates to the technical field of metal surface treatment, in particular to a blueing process for a strip steel surface using an electroplating method. Background Art

[0002] The process of heating a metal workpiece to an appropriate temperature in air + water vapor or chemicals to form a protective blue or black oxide film on its surface is called bluing, also known as blackening.

[0003] Chinese patent application publication number CN110724902A discloses a "pollution-free steel gas blackening process," which includes the following steps: cleaning parts; loading the parts into a furnace and simultaneously adding a catalyst; evacuating the furnace to remove air; introducing a nitrogen-based protective atmosphere, heating to 500-600°C, switching to pulsed exhaust, and heating for 60-120 minutes; cooling to an oxidation treatment temperature of 400-500°C, converting the nitrogen-based protective atmosphere in the furnace to an oxidizing atmosphere, and holding the temperature for 30-300 minutes; removing the oxidizing atmosphere, introducing nitrogen, and cooling to 200-480°C; removing the parts from the furnace and immersing them in oil; and removing the oil after the parts have cooled. This typical oxidation bluing process is relatively complex and requires numerous parameters to be controlled, making it inconvenient to operate and easily resulting in poor bluing of the steel or steel parts, an unsightly oxide film, or defects in the oxide film, which compromises the corrosion protection.

[0004] The Chinese patent application with publication number CN 104060262 A discloses a “new process for blackening the surface of castings”, which includes the following steps: (1) degreasing: placing the casting into a degreasing tank with a degreasing solution concentration of 60 g / L and a solution temperature of 70-80°C, soaking for 5-10 minutes, taking out the casting, and rinsing it with clean water for 3-4 times; (2) pickling: placing the degreasing casting into a pickling tank for pickling with an industrial hydrochloric acid solution concentration of 20-30% for 5-10 minutes, then taking out the casting, and rinsing it with clean water for 3-4 times; (3) degreasing: immersing the pickled casting into a degreasing solution for degreasing treatment for 15-35 minutes, then taking out the casting, and rinsing it with clean water for 3-4 times; (4) Blackening preparation: add 25-45 parts of sodium hydroxide, 15-25 parts of potassium persulfate, 10-18 parts of potassium sodium tartrate, 5-8 parts of additives, and 1000 parts of water into a blackening tank by weight and stir evenly; (5) Blackening: put the degreased casting into a blackening tank for blackening treatment, control the solution temperature at 10-30°C, and treat for 5-8 minutes, then take out the casting and rinse with clean water 3-4 times; (6) Post-treatment: immerse the blackened casting in soap solution for 3-5 minutes, the solution temperature is 40-50°C, then take out the casting and put the casting into dehydration anti-rust oil, take it out after 1-2 minutes, and let the black film on the surface of the casting dry completely. The blueing process using chemical drugs as a representative example is relatively complicated, and the chemicals used in the chemical method are more polluting to the environment, which is not conducive to environmental protection and long-term industrial production.

[0005] Steel strips that require rust prevention also undergo a bluing treatment during production. The most common bluing process involves heating the strip in air or immersing it directly in a concentrated oxidizing solution. This treatment forms a dense oxide film on the strip's surface, effectively enhancing its rust resistance. During bluing, the strip is typically hoisted to the loading position of a heating furnace, then heated and cooled. The bluing is complete upon cooling.

[0006] The Chinese patent application with application number CN 117244952 A discloses "a strip blueing production line". The strip steel coil is arranged in a feeding mechanism and is continuously fed through the feeding mechanism. The strip steel is first cleaned by a cleaning mechanism to remove impurities attached to the surface, and then enters a first heating and cooling mechanism. The first heating and cooling mechanism preheats the strip steel, and the strip steel is cooled after preheating. The cooled strip steel enters a tension adjustment mechanism, and the tension adjustment mechanism adjusts the tension in the strip steel to prevent the strip steel from deforming. The cooling and drying mechanism cools and dries the strip steel to remove the cooling water attached to the surface of the strip steel, and then the strip steel enters a second heating and cooling mechanism to be heated to the temperature required for blueing for blueing treatment. The blued strip steel is cooled again, and the cooled strip steel enters a conveying mechanism. The conveying mechanism is used to convey the strip steel so that the strip steel continues to move in the production line, and the unloading and winding mechanism coils the blued strip steel for easy storage. The repeated heating and cooling process during strip production greatly affects production continuity and efficiency. In addition, water cooling is generally used to cool the strip during the bluing process. After cooling, residual moisture will remain on the strip, causing the strip to rust during storage, affecting the production quality of the strip. Summary of the Invention

[0007] The present invention provides a blueing process for the surface of steel strips using an electroplating method. Electroplating equipment is used to electrolyze a sodium hydroxide solution to cause a bluing reaction on the surface of the steel strips, thereby forming a dense oxide film on the surface of the steel strips. This realizes the blueing treatment of the steel strips at room temperature and improves the production efficiency of the steel strips.

[0008] In order to achieve the above object, the present invention adopts the following technical solutions:

[0009] A blueing process for the surface of steel strips using electroplating includes degreasing, pickling, electrolysis, rinsing, and drying. The specific steps are as follows:

[0010] (1) Cleaning and activating the strip steel after degreasing and pickling;

[0011] (2) injecting electroplating solution into the electroplating tank, wherein the electroplating solution is a sodium hydroxide solution with a mass concentration of 5% to 10%;

[0012] (3) Adjust the temperature of the plating solution to 50-80°C;

[0013] (4) passing an electric current into the electroplating solution, the current power is 16-18 kVA;

[0014] (5) After the strip passes through the plating solution in the plating tank, an oxide film is formed on the surface. The traveling speed of the strip is 80-100 m / min.

[0015] (6) The steel strip is rinsed and dried after leaving the electroplating tank.

[0016] Furthermore, in step (1), a low-temperature plasma generator is used to clean and activate the surface of the steel strip.

[0017] Furthermore, in step (5), the oxide film formed on the surface of the strip is dark blue, with an average film thickness of 1.1 to 1.4 μm; the composition of the oxide film is Fe3O4; and the electrolytic corrosion depth is 0.93 to 0.97 mm / a.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] 1) Use electroplating to achieve blueing treatment on the surface of the steel strip; pass current into the electrolyte to electrolyze H2O molecules to produce O 2+ ions, O 2+ The ions are attracted by the negative potential applied to the strip, and the active O 2+ The ions react with the surface of the strip to form iron compounds and obtain a blue oxide film;

[0020] 2) The prepared blue oxide film is dense and beautiful, with a simple production process, low cost, and easy operation, which is conducive to industrial production and pollution-free;

[0021] 3) The blueing treatment of electroplating is realized at room temperature. No heating is required before the blueing treatment and no cooling is required after the treatment. This ensures the continuity of strip production, improves production efficiency, and has broad application prospects. DETAILED DESCRIPTION

[0022] The present invention discloses a blueing process for a steel strip surface using an electroplating method, which includes degreasing, pickling, electrolysis, rinsing, and drying. The specific steps are as follows:

[0023] (1) Cleaning and activating the strip steel after degreasing and pickling;

[0024] (2) injecting electroplating solution into the electroplating tank, wherein the electroplating solution is a sodium hydroxide solution with a mass concentration of 5% to 10%;

[0025] (3) Adjust the temperature of the plating solution to 50-80°C;

[0026] (4) passing an electric current into the electroplating solution, the current power is 16-18 kVA;

[0027] (5) After the strip passes through the plating solution in the plating tank, an oxide film is formed on the surface. The traveling speed of the strip is 80-100 m / min.

[0028] (6) The steel strip is rinsed and dried after leaving the electroplating tank.

[0029] Furthermore, in step (1), a low-temperature plasma generator is used to clean and activate the surface of the steel strip.

[0030] Furthermore, in step (5), the oxide film formed on the surface of the strip is dark blue, with an average film thickness of 1.1 to 1.4 μm; the composition of the oxide film is Fe3O4; and the electrolytic corrosion depth is 0.93 to 0.97 mm / a.

[0031] In order to more intuitively embody the present invention, the embodiments of the present invention are further described in conjunction with examples. The following examples are only preferred specific embodiments of the present invention, but the scope of protection of the present invention is not limited thereto. Any technical solution that can be obviously obtained by a person skilled in the art within the technical scope disclosed in the present invention, including simple changes or equivalent replacements, is within the scope of protection of the present invention.

[0032] [Example]

[0033] In this embodiment, the strip steel surface is bluing treated by electroplating. The main process parameters are shown in Table 1, and the parameters of the oxide film on the strip steel surface are shown in Table 2.

[0034] Table 1 Main process parameters

[0035] Example Sodium hydroxide concentration, % Temperature, °C Current power, KVA Strip traveling speed, m / min 1 6.5 60 16.8 91 2 5.2 65 16.5 83 3 8.4 58 17.1 93 4 7.9 52 17.4 88 5 9.8 77 17.6 97

[0036] Table 2 Parameters of oxide film on strip surface

[0037] Example color Appearance judgment Average film thickness, μm Oxide film composition Electrolytic corrosion depth, mm / a 1 Dark blue Uniform and beautiful without bad pixels 1.21 <![CDATA[Fe3O4]]> 0.943 2 Dark blue Uniform and beautiful without dead pixels 1.32 <![CDATA[Fe3O4]]> 0.961 3 Dark blue Uniform and beautiful without dead pixels 1.14 <![CDATA[Fe3O4]]> 0.937 4 Dark blue Uniform and beautiful without bad pixels 1.28 <![CDATA[Fe3O4]]> 0.949 5 Dark blue Uniform and beautiful without dead pixels 1.37 <![CDATA[Fe3O4]]> 0.955

[0038] The above description is only a preferred specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any technician familiar with the technical field, within the technical scope disclosed by the present invention, who makes equivalent replacements or changes based on the technical solution and inventive concept of the present invention, should be covered by the scope of protection of the present invention.

Claims

1. A blueing process for the surface of a steel strip using an electroplating method, characterized in that: It includes degreasing, pickling, electrolysis, rinsing and drying processes; the specific steps are as follows: (1) Cleaning and activating the strip steel after degreasing and pickling; (2) injecting electroplating solution into the electroplating tank, wherein the electroplating solution is a sodium hydroxide solution with a mass concentration of 5% to 10%; (3) Adjust the temperature of the plating solution to 50-80°C; (4) passing an electric current into the electroplating solution, the current power is 16-18 kVA; (5) After the strip passes through the plating solution in the plating tank, an oxide film is formed on the surface. The traveling speed of the strip is 80-100 m / min. (6) The steel strip is rinsed and dried after leaving the electroplating tank.

2. The metal surface bluing process using electroplating according to claim 1, characterized in that: In the step (1), a low-temperature plasma generator is used to clean and activate the surface of the steel strip.

3. The metal surface bluing process using electroplating according to claim 1, characterized in that: In the step (5), the oxide film formed on the surface of the strip is dark blue, with an average film thickness of 1.1 to 1.4 μm; the composition of the oxide film is Fe3O4; and the electrolytic corrosion depth is 0.93 to 0.97 mm / a.