JPS61222736A - Corrosion-resistant coated steel pipe and coating forming method thereof - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is generally installed and used as a brake noise, fuel/eve, or other refueling/air supply path ring in vehicles such as automobiles. In particular, on the outer circumferential surface of double-wound steel pipes, seamless steel pipes, or electric resistance welded steel pipes that have a copper plating film on the surface of the pipe, or have a relatively small diameter of about 5X or less, The present invention relates to improvements in a corrosion-resistant coated steel pipe having a baked coating layer and a method for forming the coating.

[Conventional technology]

Conventionally, as shown in Fig. 3, the corrosion-resistant coated steel pipe for lumberjacks has generally been coated with a copper electroplating film (Iz) formed on the outer periphery of a pipe member (Ql) by an electroplating method (k), and a zinc electroplating film (Iz) formed directly on the surface of the pipe member (Ql). The layer αj is deposited and polymerized, and a baked coating layer (1
4 and was put into practical use.

[Problem that the invention seeks to solve]

However, in the conventional method, when forming the baked coating layer α, heat treatment is performed to a high temperature of 200°C or more depending on the type of paint desired, so that the baked coating layer after treatment is It does not cause partial blisters, cracks, or peeling in the layer α, which often results in peeling during bending into various shapes as products, which impairs quality value. It had the disadvantage of deteriorating impact resistance.

In order to effectively solve the above-mentioned conventional problems, the present invention solves the problem of the copper electroplating film O2 directly adhered to the surface as a cause of blistering, cracking, peeling, etc. in the baked coating layer α. It was also determined that the polymerized zinc electroplated layer (19) generated a brittle diffusion layer between it and the electroplated film α2 due to heat treatment, and that this was caused by changes in hardness, internal structure, stress, etc. In particular, on the surface of the copper 1! plating film, an electrolytic plating layer of zinc is deposited and polymerized, with a layer of nickel or iron formed by an electric can method or a chemical plating method being interposed;
The presence of the nickel or iron plating layer completely prevents the formation of a diffusion layer between the steel electroplating layer and the zinc electroplating layer during subsequent heat treatment, and prevents blistering, cracking or peeling of the baked coating layer. It is an object of the present invention to propose a corrosion-resistant coated steel pipe and a method for forming the coating, which can eliminate such concerns and sufficiently satisfy corrosion resistance and impact resistance.

[Failure to solve the problem]

The present invention provides the 11! l
A metal layer of nickel or iron is laid on the surface of the I film, and a zinc electric key layer is fracture-polymerized, and a baking coating layer is further applied to the surface of the zinc electric key layer with or without a chromate coating. The main feature is a corrosion-resistant coated steel pipe composed of a steel pipe having an electrolytic coating on the outer periphery of the pipe member, which has an electroplated coating made of steel that has been pre-treated by degreasing, derusting, etc. Alternatively, a nickel or iron plating layer is laid down using a chemical plating method, a zinc electrolytic plating layer is applied and polymerized on the top surface of the plating layer using an electroplating method, and then a chromate coating is applied to the top surface of the plating layer. The gist of the present invention is a method of forming a coating by forming a baked coating layer through baking treatment after coating with a paint. explain.

Fig. 1 is a plan view of a corrosion-resistant coated steel pipe constructed by the coating forming method according to an embodiment of the present invention;
- A partially cutaway sectional view taken along line A, (1)
is made of steel strip material with 3μ thick copper T on both sides.
A tube member made by double wrapping in the width direction with a ruptured membrane (2), and then heat-soldering the polymerization phase using the electroplated membrane as a solder material, before degreasing, rust removal, etc. A plating layer (4) of nickel or iron by an electroplating method, or nickel by a chemical plating method is interposed on the surface of the nuclear electroplating film on the outer periphery of the tube member (1) having a treated copper key film (2). On the upper surface of the fund layer (4), a zinc electric key layer (3) is formed by adhesion and polymerization using the electric key method, and the upper surface of the electric plating layer is coated with paint with or without chromate coating treatment. A baked coating film layer (5) is formed by baking treatment after application.

Regarding the thickness of the plating layer (4), the type of paint,
Although it varies depending on the baking temperature, time conditions, thickness of the coating layer, etc., it is preferable to lay the layer with a thickness of 2μ or more.

[For production]

Since the present invention comprises the above-mentioned coating structure and method for forming the coating, the nickel or iron metal layer ( 4) completely prevents the formation of a diffusion layer between the steel electric key layer (2) and the zinc electroplating layer (3) even during the subsequent heat treatment during baking after coating with paint. It is.

〔Example〕

Example 1. Pipe member: Material: 5TPG 38, outer diameter 109, wall thickness 0.7), length 500X, with a 3μ copper coating on the inner and outer peripheries, and was degreased and degreased by the usual method. Perform rust pretreatment.

・Nickel plating treatment: A plating layer consisting of 240% nickel sulfate, 40% nickel chloride, 30% boric acid, pH 4, 6, temperature 45℃, cathode current density 3A/
Electricity was applied for 10 minutes at da12 to obtain a nickel plating layer having a layer thickness of 5 μm.

·zinc! Plating treatment: Zinc oxide 30%, soda ratio 60%
%, using an electroplated layer consisting of 70% caustic soda,
After applying electricity for 15 minutes at a temperature of 5° C. and a cathode current density of 3 A/dm, and washing with water, a chromate film treatment was performed, and the film was washed again with water and dried to obtain an electroplated layer of zinc having a layer thickness of 8 μm.

・Baking coating treatment: Epoxy resin powder coating (manufactured by Dainippon Toyo Co., Ltd., product name V-PET◆1340) is applied by electrostatic coating method, and then heat-treated at 180°C for an addition period to reduce the average layer thickness. A black baked-on coating layer of approximately 6 microns was obtained.

Example 2 - Pipe member: Same as Example 1 - Nickel plating treatment: Using chemical Niracle plating solution (manufactured by Uezai Kogyo, product name Nimden 5X), immersion treatment was carried out at a temperature of 12°C for 12 minutes, A nickel plating layer having a layer thickness of 4 μm was obtained.

- Zinc electric key processing...Same as Example 1. Baking coating treatment: Spraying acrylic resin paint (manufactured by Dainippon Toyo Co., Ltd., product name Duraclone CW), then applying 1
Heat treatment was performed at 80℃ for (up to) minutes, and the average layer thickness was approximately (9
) A black baked-on coating film layer consisting of μ was obtained.

Example 3 - Pipe member... Same as Example IK - Iron plating treatment... Ferrous sulfate 250%, ferrous chloride 4
0% ammonium chloride and 20% ammonium chloride, and the cathode current density was 3 A/drn at a temperature of 40°C.
Electricity was applied for 10 minutes to obtain an iron plating layer having a layer thickness of 5 μm.

・Zinc electroplating treatment: Same as Example 1 ・Baking coating treatment: Same as Example 1 Comparative example ・Pipe member: Same as Example IK ・Zinc plating treatment: Same as Example 1, baking Painting treatment: The results of visual appearance inspection after the baking treatment and subsequent bending of the products of the present invention (Examples 1.2 and 3) and the conventional product (comparative example), which are the same as in Example 1, are shown. , listed in Table-IK below.

Table 1 (The bending process was determined using a state in which a cylindrical body-tube member with a diameter of 50 mm or more was wound into a coil.) [Effects of the Invention] As explained above, the corrosion-resistant coated steel pipe and In particular, the method for forming the coating is to interpose a nickel or iron plating layer (4) on the surface of the electroplated film (2) of the steel, and then deposit and polymerize a zinc electroplated layer (3) on the top surface. Therefore, the nickel or iron plating layer (4)K prevents subsequent baking from forming the steel key layer (4) during the heat treatment.
2) and the zinc electroplated layer (3) are completely prevented from diffusing between each other, so there is no concern about partial blistering, cracking, or peeling of the baked coating layer (5), and there is no need to worry about the problem of partial swelling, cracking, or peeling of the baked coating layer (5). The present invention provides an extremely useful corrosion-resistant coated steel pipe and a method for forming the coating, which can sufficiently increase quality value and improve corrosion resistance and impact resistance without the risk of peeling or the like.

[Brief explanation of drawings]

Fig. 1 is a plan view of a corrosion-resistant coated steel pipe constructed by a coating forming method according to an embodiment of the present invention, Fig. 2 is a partially cutaway cross-sectional view enlarged from Fig. 1 A-A@, and Fig. 3 is an enlarged partially cutaway cross-sectional view showing an example of a conventional product. (1)...Pipe member, (2)...Copper electrolytic coating, (3)
... Zinc electroplated layer, (4) ... Nickel or iron plating layer, (5) ... Baked coating layer. Patent applicant: Usui Kokusai Sangyo Co., Ltd. Agent: 1) Yoshihisa ;NoJ

Claims (1)

[Scope of Claims] 1) A nickel or iron plating layer (4) is laid on the surface of the outer periphery of the tube member (1) having a copper electroplating film (2), and a zinc electroplating layer (4) is interposed therebetween. 3) and further has or does not have a chromate coating.
A corrosion-resistant coated steel pipe characterized in that it has a baked-on coating layer (5) on its surface. 2) Electroplated copper film (
A plating layer (4) of nickel or iron is interposed on the surface of the electroplated film on the outer periphery of the tube member (1) having a nickel or iron layer (4) by electroplating or chemical plating, and the top surface of the plating layer (4) is electroplated. A zinc electroplating layer (3) is deposited and polymerized, and the top surface of the electroplating layer is treated with or without a chromate coating,
Baked coating layer (5
) A method for forming a coating on a corrosion-resistant coated steel pipe.