Highly corrosion-resistant copper tube

Abstract

A copper tube which can exhibit an improved resistance against ant nest corrosion, and which is suitably usable in air-conditioning equipment and refrigerating equipment, to advantageously extend a service life of the equipment produced by using the copper tube. The copper tube contains 0.05-1.0% by weight of P (phosphate) and the balance consisting of Cu (copper) and inevitable impurities.

Description

CROSS REFERENCE TO RELATED APPLICATION[0001]This application is a continuation of the International Application No. PCT / JP2014 / 052418 filed on Feb. 3, 2014, which claims the benefit under 35 U.S.C. §119(a)-(d) of Japanese Application No.2013-055963 filed on Mar. 19, 2013, the entireties of which are incorporated herein by reference.BACKGROUND OF THE INVENTION[0002]1. Field of the Invention[0003]The present invention relates to a highly corrosion-resistant copper tube, and more particularly relates to a copper tube suitably usable as a heat transfer tube and a refrigerant tube in air-conditioning equipment and refrigerating equipment, for example.[0004]2. Description of Related Art[0005]A tube made of a phosphorous deoxidized copper (JIS-H3300-C1220T) having excellent properties in terms of corrosion resistance, brazability, heat conductivity and bending workability, for example, has been mainly used as the heat transfer tube in the air-conditioning equipment, the refrigerant tube in...

AI Technical Summary

Benefits of technology

The present invention provides a copper tube with improved resistance against ant nest corrosion, which is commonly found in damp environments such as air-conditioning and refrigerating equipment. By increasing the P content of the copper tube, its resistance against ant nest corrosion is significantly improved compared to conventional copper tubes. This results in a longer service life for the equipment that uses the copper tube. The method for improving the corrosion resistance of the copper tube involves forming it with a material containing 0.10-1.0% by weight of P and the balance consisting of Cu and inevitable impurities. The practical copper tube provided by the invention is superior to conventional copper tubes in terms of its anti-corrosion property.

Problems solved by technology

However, it is recognized that the above-described phosphorous deoxidized copper tube used in the air-conditioning equipment and the refrigerating equipment suffers from generation of so-called “ant nest corrosion” (or “formicary corrosion”) which is an unusual corrosion that progresses in the form of an ants' nest from the surface of the tube in a direction of its wall thickness.

It is known that generation of the ant nest corrosion is particularly remarkable where the phosphorous deoxidized copper tube is used as a conduit in the air-conditioning equipment and the refrigerating equipment, which conduit is liable to dewing.

Once the ant nest corrosion is generated, it progresses rapidly and penetrates through the wall of the copper tube in a short time, giving rise to a problem that the equipment becomes unworkable.

However, the copper tube obtained by reducing the P content has not yet achieved a sufficiently high resistance against the ant nest corrosion which is comparable to that of the oxygen-free copper tube.

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