JPH0517319B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention generally applies to brake pipes, fuel pipes, or other refueling pipes in vehicles such as automobiles.
A double-wound steel pipe with a relatively small diameter of about 25 mm or less, which is used as an air supply path, etc., and has a pipe-formed or copper-plated metal on the peripheral surface for cleanliness, or In particular, the present invention relates to improvements in corrosion-resistant and impact-resistant coated steel pipes having a baked-on coating layer on the outer circumferential surface of electric resistance welded steel pipes, and a method for forming the coating. [Prior Art] Conventionally, as this type of corrosion-resistant/impact-resistant coated steel pipe, as illustrated in FIG.
2, an electroplated layer 13 of zinc is directly applied and polymerized, and a baked coating layer 14 is further formed on the surface of the electroplated layer 14 for corrosion resistance and external impact resistance. It was put to practical use. [Problems to be Solved by the Invention] However, in the conventional method described above, when forming the baked coating layer 14, depending on the type of paint desired, heat treatment is performed to a high temperature of 200° C. or higher. This causes partial blistering, cracking, or peeling of the baked coating layer 14 after treatment, and furthermore, during subsequent bending into various shapes as products, peeling often occurs and quality value is impaired. In addition to this, there was a problem in that corrosion resistance and impact resistance deteriorated. In order to effectively solve the above-mentioned conventional problems, the present invention solves the problem of polymerization directly deposited on the surface of the electroplated copper film 12 as a cause of blistering, cracking, peeling, etc. in the baked coating layer 14. Based on the judgment that the zinc electroplated layer 13 generated a brittle diffusion layer between it and the electroplated film 12 due to the heat treatment, this was caused by changes in hardness, internal structure, stress, etc. In particular, a zinc or iron plating layer is deposited and superposed on the surface of the copper electroplating layer with a nickel or iron plating layer formed by electroplating or chemical plating, and then the nickel or iron plating layer is deposited and polymerized. By intervening, the formation of a diffusion layer between the copper electroplating layer and the zinc electroplating layer during the subsequent heat treatment is completely prevented, eliminating concerns such as blistering, cracking, or peeling of the baked coating layer. The object of the present invention is to propose a corrosion-resistant/impact-resistant coated steel pipe that can sufficiently satisfy corrosion resistance and impact resistance, and a method for forming the coating. [Means for Solving the Problem] The present invention provides a method in which a nickel or iron plating layer is interposed on the surface of the outer periphery of a pipe member having a copper electroplating film, and then a zinc electroplating layer is deposited and polymerized. Furthermore, the gist is a corrosion-resistant/impact-resistant coated steel pipe comprising a baking coating layer on the surface of the electroplated zinc layer with or without a chromate coating. A nickel or iron plating layer is interposed by an electroplating method or a chemical plating method on the surface of the outer periphery of a pipe member having an electroplated copper film that has been pretreated to prevent rust, etc., and on the top surface of the plating layer,
An electroplated layer of zinc is deposited and polymerized by the electroplating method, and then a chromate coating is applied or not applied to the electroplated layer to form a baked coating layer that accompanies baking treatment after coating with paint. Embodiments of the present invention will be described below with reference to the drawings. Fig. 1 is a plan view of a corrosion-resistant/impact-resistant coated steel pipe constructed by the coating forming method according to an embodiment of the present invention, and Fig. 2 is a partially cutaway sectional view taken along line A-A in Fig. 1. 1 is made of a steel band material, has an electroplated copper film 2 of about 3μ thick on both sides of the material, is double-wound in the width direction, and then heat-solders the polymerized peripheral surface using the electroplated film as a solder material. This is a pipe member which is made by electroplating, and the surface of the electroplated film on the outer periphery of the pipe member 1 is coated with nickel or iron, or by electroplating. A nickel plating layer 4 is laid down by a chemical plating method,
On the top surface of the plating layer 4, an electroplating layer 3 of zinc is formed by an electroplating method.
The electroplated layer is formed by deposition polymerization, and then a chromate coating treatment is performed or not on the upper surface of the electroplated layer, and a baked coating layer 5 is formed by baking treatment after coating with paint. It is. The thickness of the plating layer 4 varies depending on the type of paint, baking temperature, time conditions, thickness of the coating layer, etc., but it is preferably 2μ or more. [Function] Since the present invention has the above-mentioned coating structure and method for forming the coating, the nickel or iron plating layer 4 interposed between the copper electroplating layer 2 and the zinc electroplating layer 3 As a result, even during the subsequent heat treatment during baking after coating with paint, the formation of a diffusion layer between the copper electroplating layer 2 and the zinc electroplating layer 3 is completely prevented.

[Table] Obtained.

[Table] The results of visual inspection of the products of the present invention (Examples 1, 2, and 3) and the conventional product (comparative example) after baking treatment and subsequent bending are shown in Table 1 below. Describe it.

[Table] Judgment was made based on the state in which the tubular member was wound in a coil shape around the cylindrical body. )
[Effects of the Invention] As explained above, the corrosion-resistant/impact-resistant coated steel pipe and the coating forming method thereof according to the present invention particularly include interposing a nickel or iron plating layer 4 on the surface of the copper electroplating film 2. Since the electroplated layer 3 of zinc is deposited and polymerized on the upper surface of the plate, the electroplated layer 2 of copper and the electroplated layer of zinc are formed by the electroplated layer 4 of nickel or iron during the subsequent heat treatment during baking. As a result, diffusion between the layers 3 is completely prevented, so there is no concern about partial swelling, cracking, or peeling in the baked coating layer 5, and there is no fear of peeling during bending. The present invention provides an extremely useful corrosion-resistant/impact-resistant coated steel pipe and a method for forming the coating, which can sufficiently increase quality value and improve corrosion resistance and impact resistance.

[Brief explanation of drawings]

Fig. 1 is a plan view of a corrosion-resistant/impact-resistant coated steel pipe constructed by a coating forming method according to an embodiment of the present invention, and Fig. 2 is a partially cutaway enlarged view of line A-A in Fig. 1. FIG. 3 is an enlarged partially cutaway cross-sectional view showing an embodiment of a conventional product. 1... Pipe member, 2... Copper electroplating layer, 3... Zinc electroplating layer, 4... Nickel or iron plating layer, 5
...Baked paint coating layer.

Claims (1)

[Claims] 1. A nickel or iron plating layer 4 is laid on the surface of the outer periphery of the tube member 1 having the copper electrolytic coating 2, and a zinc electroplating layer 3 is deposited and polymerized; A corrosion-resistant and impact-resistant coated steel pipe characterized in that it has a baked-on coating layer 5 on the surface of the electroplated layer 3 of zinc. 2. A corrosion-resistant and impact-resistant coated steel pipe, characterized in that the electroplated layer 3 of zinc has a chromate coating on its surface. 3. On the surface of the electroplated film on the outer periphery of the pipe member 1, which has the copper electroplated film 2 which has been pretreated such as degreasing and derusting,
A nickel or iron plating layer 4 is laid down by an electroplating method or a chemical plating method, an electroplating layer 3 of zinc is deposited and polymerized on the upper surface of the electroplating layer 4, and a paint is applied on the upper surface of the electroplating layer. 1. A method for forming a coating on a corrosion-resistant/impact-resistant coated steel pipe, comprising forming a baked-on coating layer 5 through a baking process.