JPH0311517Y2 - - Google Patents

Description

[Detailed description of the invention] This invention has been installed and used in many places, such as automobile brake pipes, various machines, devices, etc., as oil supply, air supply, etc. The present invention relates to improvements in the corrosion-resistant resin coating structure of thin-walled metal steel pipes with small diameters.

The conventional corrosion-resistant resin coating structure for metal steel pipes consists of a single layer using a fluororesin selected for its corrosion resistance, on a zinc plating layer with a chromate coating on the outer peripheral surface of the steel pipe material. The fused coating layer was applied and was ready for practical use.

However, in view of the fact that such a single layer cannot be made thick (usually about 10μ to 15μ) due to sagging during fusion coating or uneven layer thickness, etc. During various bending processes for products made from steel pipe materials or during transportation between processes, damage, dents, and scratches often occur not only to the fusion coating layer but also to the chromate coating and zinc plating layer. However, due to the pinholes scattered on the coating layer, the corrosion resistance is still insufficient, and further improvement is desired.

An object of the present invention is to provide a resin coating structure for a thin metal steel pipe that provides a coating layer with a similar thickness, has no pinholes on the coating layer, and has excellent corrosion resistance.

According to the present invention, a copper plating film 2 is provided at least on the outer peripheral surface side of the steel pipe material 1 as required, and a zinc plating film with a chromate film 4 on the surface is provided on the plating film or on the steel surface. A corrosion-resistant resin for a small diameter thin-walled metal steel pipe, which has a layer 3 and further comprises on the chromate coating, at least two coating layers 5 and 6 of fluororesin fused to each other and polymerized. The gist is the covering structure.

Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings. A steel pipe material 1 having a relatively small diameter and thin wall has a wall thickness of about 2 m/m or less, which is about the same as the pipe diameter, and has a copper plating film 2 on at least the outer peripheral surface side. or not, and has a zinc plating layer 3 on which a chromate film 4 is applied on the surface of the plating film, or on the surface of the steel, and vinylidene fluoride, vinylidene fluoride, etc. on the chromate film. Consisting of at least two layers of vinyl fluoride, ethylene tetrafluoride, ethylene chloride trifluoride, or a copolymer thereof, and formed by adhesion polymerization with coating layers 5 and 6 of fluororesin fused to each other. This is what happens.

As described above, according to the present invention, the fusion coating layers 5 and 6
Since it is formed by depositing and polymerizing in at least a multi-layered structure, the overall layer thickness can be made thick, so that it can be easily bent during subsequent bending as a product, or during transportation between processes. It is easy to handle, and at the same time it can prevent and reduce damage, dents, scratches, etc. that extend to the chromate coating 4 and the zinc plating layer 3, and the upper coating layer 6 and the lower coating layer 5 are fused to each other, even if there is a pinhole in the lower coating layer 5, the pinhole will be buried when the upper coating layer 6 is fused, and due to the synergistic effect of these This makes it possible to further improve corrosion resistance.

[Brief explanation of the drawing]

FIG. 1 is a plan view of a small-diameter thin-walled metal steel pipe having a corrosion-resistant resin coating structure according to an embodiment of the present invention;
The figure is an enlarged sectional view taken along line A--A in FIG. 1, with a partial cutout, and FIG. 3 is an enlarged sectional view taken with a partial cutout according to another embodiment. 1... Steel pipe material, 2... Copper plating film, 3... Zinc plating film, 4... Chromate coating, 5, 6... Fusion coating layer of fluororesin.

Claims (1)

[Scope of utility model registration request] A zinc plating layer 3 with a chromate coating 4 on the surface is provided on at least the steel skin surface on the outer circumference side of the steel pipe material 1, and furthermore, on the chromate coating, at least two layers are formed and are fused to each other. Fluororesin coating layers 5 and 6
A corrosion-resistant resin-coated structure for a small diameter thin-walled metal steel pipe, characterized in that it is formed by coating and polymerizing.