KR100579410B1 - Manufacturing method of Zn electrodeposited steel sheet for good corrosion resistance and hardness and Zn electrodeposition solution for the method - Google Patents

Abstract

The present invention relates to a method for producing a zinc electroplated steel sheet having good corrosion resistance and surface hardness, and to a zinc electroplating solution for the chloride bath therefor. The present invention relates to two components consisting of iron chloride and sodium tungsterator during zinc electroplating in an acid chloride electro zinc plating bath. To prepare a first solution by melting the iron: tungsten ratio 1: 0.05 to 1: 3 in water and then combined; Preparing the second solution by further adding the prepared first solution so that the sum of the bimetallic components of iron and tungsten is 0.01 to 0.1 mmol / liter in the electroplating bath; And forming a Zn-Fe-W plated layer on a steel sheet as the second solution; and a method for producing a zinc electroplated steel sheet having excellent corrosion resistance and surface hardness, and a chloride bath electrolytic plating solution therefor. It is about.

Electroplated Steel Sheet, Chloride Bath, Iron, Tungsten

Description

Manufacturing method of Zn electrodeposited steel sheet for good corrosion resistance and hardness and Zn electrodeposition solution for the method

The present invention relates to a method for producing a zinc electroplated steel sheet having good corrosion resistance and surface hardness, and to a zinc electroplating solution for chloride bath, and more particularly to a zinc electroplating steel sheet having good corrosion resistance and surface hardness in a chloride-based zinc plating bath. A method and a chloride bath zinc electroplating solution for the same.

In general, zinc electroplating materials in surface treatment products have many advantages in terms of ease of plating, cost and corrosion resistance, and are widely used as materials for home appliances, construction, and automobiles. In order to improve the productivity of such a steel sheet, high current density plating is mainly performed, and when used for painting, the surface appearance of the plating layer should be excellent.

In addition, it should be well processed without peeling of the plating layer where the deep processing for the final product is performed. As the zinc electroplating bath, chloride bath, sulfate bath, cyan bath and neutral salt bath are used. Among them, the chloride bath is known to be suitable for high current density plating because of its excellent electrical conductivity. Therefore, the coating amount should be increased by a certain amount because it depends on the coating amount. Therefore, as a result, plating adhesion becomes unstable and workability becomes weak. In addition, due to the low hardness of the plated layer, pressing marks become more pronounced during processing, resulting in poor striation.

In addition, U.S. Patent 4,075,066 improves the properties of plating materials by adding at least one polyoxalalkylate naphthol and Hanisa's aromatic carboxylic acid or salt for distribution of gloss, ductility and good plating current of the plating layer in ammonia free plating bath. U.S. Patent 4,146,441 is a mixture of formaldehyde in order to improve the glossiness of the plating layer and expand the plating current density in the sulfuric acid bath, and to improve the glossiness by adding an amine polymer in the chloride bath. The proposed US patent 3,855,085 improves the surface gloss by adding nonionic polyoxyethylene in a chloride bath. Selectively use calcium chloride, magnesium chloride, etc., and change the plating conditions In addition, Japanese Patent No. 61-204389 has a patent for improving the gloss by adding an additive such as amino acid, glycine, and hydroxyproline, but these are mainly limited to improving the gloss, which is the surface appearance of the galvanized layer. . In addition, patents of zinc-nickel alloy plating such as Japanese Patent Application Laid-Open No. Hei 8-225984 and Japanese Patent Laid-Open No. 6-122992 and alloy plating such as zinc-iron have been developed, but alloy plating containing a large amount of additive elements is sufficient to change the physical properties of the plating layer itself. As a result, the cost is increased.

The present invention has been made in order to solve the above problems, the present invention is to improve the corrosion resistance and hardness of the coating layer during zinc electroplating to a plating solution for zinc plating by combining a small amount of iron components and a small amount of tungsten components and An object of the present invention is to produce a steel sheet, and to achieve an effect by plating by adding an appropriate amount of a liquid composed of an iron component and a tungsten component in an appropriate ratio to a zinc plating bath based on a chloride bath.

In addition, an object of the present invention is to obtain a plating layer having excellent corrosion resistance and hardness without impairing the adhesion of the plating layer by adding a small amount of iron and tungsten components to the plating bath during the zinc electroplating in the chloride bath to precipitate on the plating surface. .

Hereinafter, the present invention will be described in more detail.

In order to solve the above problems, the present invention dissolved two components consisting of iron chloride and sodium tungsterator in zinc chloride electroplating bath in an acid chloride-based electro zinc plating bath in an iron: tungsten ratio of 1: 0.05 to 1: 3 and then dissolved in water. Combining to prepare a first solution; Preparing the second solution by further adding the prepared first solution so that the sum of the bimetallic components of iron and tungsten is 0.01 to 0.1 mmol / liter in the electroplating bath; And forming a Zn-Fe-W plating layer on a steel sheet as the second solution. The method provides a method of manufacturing a zinc electroplated steel sheet having excellent corrosion resistance and surface hardness.
In addition, dissolving the two components composed of iron chloride and sodium tungsterator in an acid chloride-based electro zinc plating bath in an iron: tungsten ratio of 1: 0.05 to 1: 3 in water to combine to prepare a first solution; And preparing a second solution to form a Zn-Fe-W plating layer on a steel sheet by further adding the prepared first solution to the electro zinc plating bath so that the sum of the two metal components becomes 0.01 to 0.1 mmol / liter. It provides a chloride bath zinc electroplating solution comprising a.

delete

In the present invention, two components consisting of iron chloride and sodium tungsterator are dissolved in water at room temperature to 60 ° C. in a ratio of iron: tungsten in a ratio of 1: 0.1 to 1: 3, and then melted by stirring for 300 seconds or more. Manufacture. When the solution prepared as described above is subjected to plating by adding 0.01 to 0.1 mmol / liter of the sum of the two metal components added to the acidic chloride type electro zinc plating bath, the electro zinc coating product having excellent corrosion resistance and surface hardness as described above. It can be manufactured.

In the present invention, when the ratio of iron and tungsten is less than 1: 0.1, it is difficult to improve the quality of the plating layer because the content of tungsten is small, and when tungsten is induced by tungsten, it is difficult to generate more tungsten on the plating layer. Do not. Therefore, there is no increase in corrosion resistance and hardness of the plating layer, and current efficiency decreases due to excessive tungsten.

When the concentration of the two metals (iron + tungsten) is 0.01 mmol / liter or less, the additive element is too small to achieve the desired characteristics of the plated layer. If the concentration is greater than 0.1 mmol / liter, the element of the plating layer is added to the zinc element. The increased components result in increased costs and lead to ballistic plating with black surface appearance.

The plating bath manufactured as described above may be plated under generally known zinc electroplating conditions to obtain a plated steel sheet having good quality. The electroplating by the additive element of the present invention can be applied to electro zinc plating using acid chloride regardless of the metal type and shape of the plated body, and in particular, excellent plating quality during continuous electro zinc plating of steel sheets requiring high current density plating. It is a very effective means to obtain easily.

Hereinafter, embodiments of the present invention will be described.

(Example)

The electroplating was performed under the plating solution concentration and plating conditions shown in Table 1 using a general low carbon steel sheet as a metal, and then the results of measurement of corrosion resistance and hardness of the coated steel sheet were compared. The concentration and plating conditions of the plating solution were Zn: 100 g / L, Cl: 260 g / L, plating amount: 40 g / m ² , temperature 60 ^° C., pH: 4.5, and current density of 100 A / dm ² .

Corrosion resistance in the evaluation of the characteristics of the plated layer was judged to be poor if red rust occurred before 72 hours by salt spray test by JIS standard jet-2371, and the hardness of the plated layer was 80 or less using Vickers hardness tester. Determined.

Plating Material No Iron: molar concentration ratio of tungsten Total amount added Corrosion resistance Hardness One 1: 0.01 0.5 mmol / liter Bad Bad 2 1: 0.04 0.5 mmol / liter Bad Bad 3 1: 0.05 0.5 mmol / liter Good Good 4 1: 0.06 0.5 mmol / liter Good Good 5 1: 0.1 0.5 mmol / liter Good Good 6 1: 0.5 0.5 mmol / liter Good Good 7 1: 0.8 0.5 mmol / liter Good Good 8 1: 1 0.5 mmol / liter Good Good 9 1: 2 0.5 mmol / liter Good Good 10 1: 3 0.5 mmol / liter Good Good 11 1: 3.1 0.5 mmol / liter Bad Bad 12 1: 0.5 0.0 mol / liter Bad Bad 13 1: 0.5 0.001 mmol / liter Bad Bad 14 1: 0.5 0.005 mmol / liter Bad Bad 15 1: 0.5 0.01 mmol / liter Good Anho 16 1: 0.5 0.05 mmol / liter Good Good 17 4.0 0.5 mmol / liter Good Good 18 4.1 1.0 mmol / liter Good Good 19 4.3 0.01 mol / liter Good Good 20 2.0 0.05 mol / liter Good Good 21 2.0 0.1 mol / liter Good Good 22 2.0 0.105 mol / liter Bad Bad 23 2.0 0.11 mol / liter Bad Bad

As shown in the Examples of Table 1 within the limited range of the additive element of the present invention (3 ~ 10, 15 ~ 21) shows a good corrosion resistance and hardness it can be confirmed that the plating quality is improved.

As described above, when the zinc electroplated steel sheet is manufactured by the plating bath according to the present invention, corrosion resistance and hardness in the plating layer are superior to those of the prior art.

Claims (2)

Preparing a first solution by dissolving two components consisting of iron chloride and sodium tungsterator in an acidic chloride type electro zinc plating bath and dissolving it in water at an iron: tungsten ratio of 1: 0.05 to 1: 3; Preparing the second solution by further adding the prepared first solution so that the sum of the bimetallic components of iron and tungsten is 0.01 to 0.1 mmol / liter in the electroplating bath; And Forming a Zn-Fe-W plating layer on a steel sheet as the second solution; Method for producing a zinc electroplated steel sheet excellent corrosion resistance and surface hardness comprising a. Preparing a first solution by dissolving two components composed of iron chloride and sodium tungsterator in an acid chloride-based electro zinc plating bath in an iron: tungsten ratio of 1: 0.05 to 1: 3 and then dissolving it in water; And Preparing a second solution to form a Zn-Fe-W plating layer on a steel sheet by further adding the prepared first solution to the electro zinc plating bath so that the sum of the two metal components is 0.01 to 0.1 mmol / liter; Chloride bath zinc electroplating solution comprising a.