KR0125318B1 - MANUFACTURING METHOD FOR PYRO-BLACK Zn-Cu ALLOY COATED STEEL SHEET - Google Patents

Abstract

The fabrication method for the black coated steel sheet includes the steps of: vacuum depositing a Zn-Cu coated layer having the copper content of 5-50 wt.% on a steel sheet, subjecting the Zn-Cu alloy coated steel sheet at 500-600 degrees centigrade in air for 1 minute, and coating the surface of the black Zn-Cu alloy coated steel sheet with a 0.5-30M of a transparent pigment.

Description

Manufacturing method of dry black zinc-copper alloy plated steel sheet

The present invention relates to a method for producing a zinc-copper alloy plated steel sheet by vacuum deposition and then oxidizing the zinc-copper alloy plated steel sheet in an air furnace to produce a black-coated steel sheet having a beautiful appearance by a dry method. .

The black steel plate has a beautiful black color on the metal surface to enhance the appearance of the product or to add value to the product with a heavy impression. It is widely used for interior and exterior boards for lighting materials, office equipment, building materials, lighting cabinets, ornaments, and the like, and recently, the use of black steel sheets has been further expanded.

Existing methods for manufacturing black steel sheet include: ① Method of forming black metal oxide by immersing in solution or chemical reaction with resin substrate by spraying solution. ② Method of forming oxide on metal surface through anodization. Etc. Japanese Patent Laid-Open Nos. 63-161176 and 62-290880 contain 0.18-20 g / L of two or more metal ions of Ag ²⁺ , Sb ²⁺ , Cu ²⁺ , Bi ²⁺ in a zinc or zinc alloy plated steel sheet. Moreover, it describes the method of blackening by spraying the aqueous solution containing 1-100 g / L of 2 or more types of metal ions among Ni2 ⁺ , Fe2 ⁺ , and Co2 ⁺ at the temperature of 50-60 degreeC. Then, chromate treatment is performed as a post treatment. On the other hand, Japanese Patent Publication No. 61-291981 discloses a zinc-nickel alloy plated steel sheet having a current density of 20 to 20 in an acidic solution having a pH of 3 or less containing a ratio of PO ₄ ^2- / NO ₃ ^- ions to 0.01 to 1. It describes about the method of blackening by performing the anodic electrolytic treatment to 40A / dm <^2> .

However, the existing black steel sheet has some disadvantages in terms of pollution and workability. In the Japanese Patent Laid-Open Publication Nos. 63-161176 and 62-290080, the waste water treatment facility must be separately prepared because the solution containing various heavy metals is used, and the concentration of metal ions must be kept constant during continuous operation. There is difficulty. In addition, when used as an inner plate material, the use range is limited because hexavalent Cr ions can be eluted by contact with human fingerprints or water due to chromate treatment performed by post treatment. In addition, the method proposed in Japanese Patent Application Laid-Open No. 61-291981 has a bad working environment, it is easy to cause pollution problem, and requires separate wastewater treatment because it has to work in strong acidity with pH less than 3. In addition, since the plated steel sheet is immersed in the strong acid bath, some elements of the plated layer are easily melted, and the current density during the electrolytic treatment should be relatively high.

The present invention focuses on improving the disadvantages of pollutants and wastewater treatment by using the solution in the above-described methods, and to produce blackened steel sheet in a manner that is easier to work than the conventional known technology and the work process is relatively simple. . That is, first, a zinc-copper alloy-coated steel sheet was made by vacuum deposition, and then a black steel sheet was manufactured by heat-treating it in an air furnace without using an aqueous solution to form an oxide film having a black color on its surface. .

Hereinafter, the manufacturing process of the present invention will be described in detail.

First, the cold rolled steel sheet, which is a base plate, was degreased under alkaline solution, and then pretreated by ultrasonic cleaning in acetone and alcohol solution. The pretreated steel sheet was charged into a vacuum chamber and evacuated to 10 ^-4 torr. After vacuum evacuation, the steel sheet is heated to a temperature of 200 ° C. in vacuum, and then zinc grains and copper metal grains are put in different evaporation sources, and power is supplied to the evaporation sources to produce zinc-copper alloy plated steel sheets by resistance heating. It was. The reason why copper is disposed in an alloy state with zinc is that the copper component of the plating layer is likely to change into a black oxide in the heat treatment process described later. Meanwhile, the amount of copper added should be between 5 and 50wt%. This is because if the amount of copper added is small, black color development does not occur, and if the amount of copper is large, corrosion resistance and adhesion are inferior.

The zinc-copper alloy plated steel sheet produced by vacuum deposition is subjected to a heat treatment process to form a black surface oxide film. That is, the zinc-copper alloy plated steel sheet was heated in an air furnace, and the temperature was heated at 500 ° C. to 600 ° C. for 1 minute. The reason why the lower limit temperature is 500 deg. C is because the oxidation of the surface of the steel sheet does not occur sufficiently below this temperature, so that the surface color does not obtain the desired black color. And the upper limit temperature is 600 ℃ because the heat treatment temperature exceeds 600 ℃ not only affects the mechanical properties of the steel sheet, but also the iron component of the metal spreads to the plating layer to change the structure of the plating layer, thus deteriorating corrosion resistance and adhesion. Because.

Lastly, the manufactured black-treated steel sheet, although showing a black color on its surface, was coated with an acrylic transparent paint in a range of 0.5 to 30 μm in order to increase corrosion resistance and weather resistance so that it may be used even in a harsh environmental atmosphere. The reason why the lower limit of the thickness of the coating is set to 0.5 µm is that the corrosion resistance and the weather resistance are not significantly increased at the thickness below this. This is because the small thickness of the applied coating does not prevent the roughness of the film itself completely and solely, so it does not protect against corrosion caused by the external environment. Since the transparent paint maintains the raw material without affecting the underlying black oxide layer, it is advantageous to apply the transparent paint when the environmental conditions are poor. In this case, even if the paint is partially peeled off, since a black oxide film exists on the surface of the plating layer, the aesthetics of the black-treated steel sheet itself are not damaged.

Hereinafter, specific embodiments of the present invention will be described.

Example 1-2

First, the general cold rolled steel sheet was degreased, charged into a vacuum chamber, and evacuated to 10 ⁻⁴ torr. After vacuum evacuation, the substrate was heated to a temperature of 200 ° C. and zinc and copper were simultaneously evaporated by a resistance heating method to adjust the evaporation rate so that the concentration of copper was 5 wt% to prepare a galvanized steel sheet. At this time, the plating amount of the plating layer was 20g / m ² . Finally, the plated steel sheet was heat-treated in an air furnace at a suitable temperature between 550 and 600 ° C. for 1 minute.

Example 3-4

In preparing a zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was manufactured by adjusting the evaporation rate so that the concentration of copper was 10wt%. Finally, the plated steel sheet was heat-treated in an air furnace at a suitable temperature between 550 and 600 ° C. for 1 minute.

Example 5-7

In preparing a zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was manufactured by adjusting the evaporation rate so that the copper concentration was 30 wt%. Finally, the plated steel sheet was heat-treated in an air furnace at a suitable temperature of 500 to 600 ° C. for 1 minute.

Example 8-10

In preparing a zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was manufactured by adjusting the evaporation rate so that the copper concentration was 50 wt%. Finally, the plated steel sheet was heat-treated in an air furnace at a suitable temperature of 550-600 ° C. for 1 minute.

Example 11-15

After the black-treated galvanized steel sheet was prepared in the same manner as in Example 3, the surface was coated with a transparent paint. The transparent paint was coated with an acrylic alkyd resin (Acrylicalkyd resting) to a thickness of 0.5 ~ 30μm, and dried at room temperature.

Example 16-20

After the black-treated galvanized steel sheet was prepared in the same manner as in Example 9, it was applied with a clear paint. The transparent paint was coated with an acrylic alkyd resin (Acrylicalkyd resting) to a thickness of 0.5 ~ 30μm, and dried at room temperature.

Comparative Example 1

In preparing the zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was manufactured by adjusting the evaporation rate so that the copper concentration was 1 wt%. And heat treatment temperature in air was heat-treated for 1 minute at 550 ℃.

Comparative Example 2-3

In preparing the zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was manufactured by adjusting the evaporation rate so that the concentration of copper was 5wt%. And heat treatment temperature in air was heat-treated for 1 minute at 550 ℃ and 650 ℃.

Comparative Example 4-5

In preparing a zinc-copper alloy plated steel sheet in the same manner as in Example 1, an alloy plated steel sheet was prepared by adjusting the evaporation rate so that the concentration of copper was 60,90 wt%. In the air, the heat treatment temperature was performed at 550 ° C. for 1 minute.

Comparative Example 6

After producing a black-treated galvanized steel sheet in the same manner as in Example 3, the coating was further performed with a transparent coating on the surface. The clear paint was coated with acrylic Alkyd resin (0.15 m thick) and dried at room temperature.

Comparative Example 7

After the black-treated galvanized steel sheet was manufactured in the same manner as in Example 9, the surface was further coated with a transparent coating. The clear paint was coated with acrylic Alkyd resin (0.15 m thick) and dried at room temperature.

Evaluation of the quality characteristics of the prepared specimens are shown in Table 1. At this time, the color was observed on the surface of the plating layer with the neck side and the color difference meter. In order to evaluate the adhesion of the plating layer, the specimen was bent 180 ° Ot, and then the degree of peeling of the plating layer was evaluated using adhesive tape (○: no peeling occurred). △: peeling partly occurred ×: peeling partly)) And to evaluate the corrosion resistance, the specimens were prepared in the size of 10cm × 15cm, and each specimen was recorded in the salt spray device according to ASTM B3317-73. It was. (◎: 98 hours or more, (circle): 24-98 hours, (triangle | delta):-24 hours x: 6 hours or less) The anti-fingerprint of the plating surface layer reduced the value of (DELTA) E before and after applying white petrolatum using a color difference meter. Finally, the weather resistance of the specimens was evaluated for the change of surface color after 6 months of outdoor exposure. (○: discoloration does not occur ×: discoloration)

As shown in Table 1, the present invention manufactures a copper-zinc alloy plated steel sheet so that the amount of copper is added in an amount of 5 to 50 wt% by vacuum evaporation, and then oxidizes it at 500 to 600 ° C. in the air. It shows that manufacturing is possible. In addition, if the transparent paint is applied after 0.5μm or more, it can be used even in a harsh environment where corrosion resistance and weather resistance are required.

As a result, the present invention can produce a simple black treated steel sheet without the facilities of pollution oil or waste water treatment than the method of manufacturing the color-treated steel sheet using a conventional aqueous solution, the interior and exterior panels of various home appliances, interior and exterior panels for building materials and ornaments Wide application is possible.

Table 1. Evaluation results of quality characteristics of black-treated galvanized steel sheet according to manufacturing conditions

Claims (2)

In the manufacturing method of black plated steel sheet, the zinc-copper alloy plated steel sheet vacuum-deposited the zinc-copper (Zn-Cu) plating layer having a copper content of 5 to 50wt% is heat-treated at a temperature of 500 to 600 ° C. in air for about 1 minute. Method for producing a dry black zinc-copper alloy plated steel sheet by applying a 0.5-30μm transparent coating on the surface of the black zinc-copper alloy plated steel sheet. The method for producing a dry black zinc-copper alloy plated steel sheet according to claim 1, wherein the transparent paint is an acrylic alkyd resin.