JPH0620452U - Immersion roll for continuous zinc plating equipment - Google Patents

Abstract

(57) [Summary] [Purpose] Without using a metal binder such as Co,
A dense coating is formed on the surface of the base metal to prevent corrosion from molten zinc, and on the coating, aluminum added to the bath, iron leaching from the base material and metal between zinc as the main component of the bath Providing a dipping roll for continuous zinc plating equipment with excellent corrosion resistance without compound precipitation. [Composition] A roll used by being immersed in a zinc bath of a zinc continuous plating facility, wherein a surface of a body of a steel body is provided with a coating of a tungsten sprayed layer, and the thickness of the coating is preferably It is characterized by being in the range of 0.02 to 1.0 mm.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a dipping roll for continuous zinc plating equipment, which has excellent corrosion resistance because it is immersed in a zinc bath of continuous zinc plating equipment and used in contact with molten zinc.

[0002]

[Prior art]

 The continuous galvanizing equipment line for steel sheets generally comprises a pretreatment step, a plating step and a finishing step. In the plating step, as shown in FIG. 2, the steel sheet to be plated 3 is a zinc bath. There is a plating bath 4 immersed in 5.

In the plating tank, there are rolls such as a sink roll 1 and a support roll 2 for supporting the material 3 to be plated. These rolls come into contact with high temperature zinc and move in the plate passing direction shown by the arrow. The roll is in severe conditions, such as coming into contact with the plated material, and especially requires measures against corrosion resistance and metal adhesion.

Molten zinc is highly corrosive to metals, has a low surface tension, and has a low viscosity, so that it also penetrates into minute gaps of a micrometer unit.

Therefore, although stainless steel materials such as SCH-13 are generally used as the material for the above-mentioned sink rolls, etc., aluminum and steel plates which are significantly corroded by zinc and are usually added to a zinc bath. Alternatively, since iron leached from the roll base material and a ternary intermetallic compound with zinc, which is the main component of the bath, are deposited, the surface of the roll body is roughened in a short period of time. The surface roughness of the roll surface is transferred as a defect to the steel plate, which is the material to be plated, and significantly deteriorates the quality of the steel plate.

Therefore, the following proposals have hitherto been made in order to improve the roll member itself or form a coating layer on the roll base material to prevent corrosion by molten zinc or precipitation of a zinc alloy on the roll. (1) Improvement of roll base material (2) Self-fluxing alloy spraying (3) Cermet spraying and overlay

[0007]

[Problems to be solved by the device]

 However, although the above (1) is disclosed in, for example, JP-A-56-112447, sufficient corrosion resistance cannot be obtained because it is a metal alloy.

Regarding the above (2), as disclosed in, for example, JP-A-1-108335, a Co, Ni or Fe-based self-fluxing alloy is sprayed on a base material to form a dense corrosion resistant coating. However, there are many examples of actual use, and some improvement effects can be seen, but the corrosion resistance is basically insufficient because it is a metal alloy.

As for the above (3), a thermal spray coating of an alloy or a mixed composition of a metal and a carbide or boride, for example, a member by WC-Co thermal spray disclosed in Japanese Patent Laid-Open No. 1-225761, or Japanese Patent Application Laid-Open No. 3-94984 discloses the build-up of carbide-containing Co alloys, but in all cases, metal components such as Co added to obtain sufficient denseness are preferentially corroded by zinc, and thus carbides. , The original excellent corrosion resistance of boride is not exhibited.

Therefore, an object of the present invention is to form a dense coating on the surface of the base material to prevent erosion from molten zinc without using a binder such as Co, and to add it to the bath in the bath. Another object of the present invention is to provide a dipping roll in which an intermetallic compound such as Al, Fe that elutes from the base material, and Zn that is the main component of the bath does not precipitate.

[0011]

[Means for Solving the Problems]

 As a result of researches aimed at achieving the above object, the inventors of the present invention have found that if metallic tungsten is thinly sprayed on the surface of the base material body of the dipping roll, a dense coating layer can be formed without a binder such as Co. It has been found that the layer has sufficient corrosion resistance to molten zinc and has low wetting with zinc (and therefore less intermetallic compound on it) and has reached the present invention.

[0012] Therefore, the present invention is for zinc continuous plating equipment in which a coating layer of tungsten metal, preferably a coating layer of tungsten metal having a thickness in the range of 0.02 to 1.0 mm, is provided on the surface of the body of a steel body. A dipping roll is provided.

As shown in FIG. 1A as an overall cross-sectional view and FIG. 1B as an enlarged cross-sectional view of the circular frame portion in FIG. 1A, the immersion roll of the present invention is a roll of its body. The tungsten 6 sprayed layer 8 is provided on the surface of the base material 6, and the thickness thereof is preferably in the range of 0.02 to 1.0 mm.

[0014]

[Action]

 In the present invention, the reason for limiting the thickness of the coating layer formed by the thermal spraying method to the range of 0.02 to 1.0 mm is as follows.

When the film thickness of the coating layer is less than 0.02 mm, zinc is allowed to permeate through the residual pores, and in the case of Tungsten thermal spraying, when it exceeds 1.0 mm, cracks occur in the coating due to residual stress during thermal spraying. , Remarkably peels off.

[0016]

【Example】

 FIG. 3 is a schematic sectional view of a test apparatus used for a zinc bath immersion test using a rod-shaped sample, which will be described below with reference to this figure.

By the apparatus of FIG. 3, a 0.12 mm-thickness tungsten sprayed layer 8 is formed on a rod-shaped sample 7 having a diameter of 20 mm and a base material made of SUS403 having a hemispherical tip, and then provided on a furnace body 9. The graphite crucible 10 was immersed in a zinc bath 5 maintained at 470 ° C. by a heater 11.

This sample 7 was able to easily remove the adhered zinc on the surface even after 100 hours, and although the coated surface after the removal was slightly oxidized at the site exposed to the atmosphere from the bath surface, it was found in the bath. No change in appearance was observed at the site where the test was performed.

[0019]

[Comparative example]

 When the rod-shaped sample 7 having no tungsten sprayed layer was immersed in the zinc bath 5 according to the procedure of the example, SUS403 and zinc reacted with each other in 24 hours of immersion, and zinc was fixed on the entire surface of the immersion site.

[0020]

[Effect of device]

 As described above, in the immersion roll of the present invention, since the roll body is protected by the coating of the tungsten sprayed layer having excellent corrosion resistance against molten zinc, the roll may be eroded by zinc. Roughness of the roll can be prevented. .

[Brief description of drawings]

FIG. 1 (a) is a sectional view of a sink roll according to the present invention, and FIG. 1 (b) is an enlarged sectional view of a circular frame portion of FIG. 1 (a).

FIG. 2 is a schematic cross-sectional view showing a sink roll in a zinc bath of continuous zinc plating equipment.

FIG. 3 is a schematic cross-sectional view of a test device used for a zinc plating bath immersion test using a rod-shaped sample.

[Explanation of symbols]

 1 sink roll 2 support roll 3 material to be plated 4 plating tank 5 zinc bath 6 roll base material 7 rod-shaped sample 8 tungsten sprayed layer 9 furnace body 10 graphite crucible 11 heater

Claims (2)

[Scope of utility model registration request] 1. A dipping roll for continuous zinc plating equipment, characterized in that a coating layer of tungsten metal is provided on the surface of the body of a steel body. 2. The immersion roll for continuous zinc plating equipment according to claim 1, wherein the coating layer is a tungsten metal layer having a thickness in the range of 0.02 to 1.0 mm.