HIGHLY CORROSION-RESISTANT COPPER TUBE
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.
1 . A heat transfer tube used in a damp environment in air-conditioning equipment and exposed to a corrosive action caused by a corrosive medium consisting of a lower carboxylic acid, which corrosive action progresses in the form of an ants' nest from a surface of the heat transfer tube in a direction of its wall thickness, wherein the heat transfer tube is a highly corrosion-resistant copper tube having a high resistance against ant nest corrosion and comprising 0.10-1.0% by weight of P and the balance consisting of Cu and inevitable impurities.
2 . The heat transfer tube according to claim 1 , comprising not lower than 0.15% by weight of P.
3 . The heat transfer tube according to claim 1 , comprising not higher than 0.8% by weight of P.
4 . The heat transfer tube according to claim 1 , comprising not higher than 0.5% by weight of P.
5 . The heat transfer tube according to claim 1 , wherein a total amount of the inevitable impurities is not higher than 0.05% by weight.
6 . A refrigerant tube used in a damp environment in refrigerating equipment and exposed to a corrosive action caused by a corrosive medium consisting of a lower carboxylic acid, which corrosive action progresses in the form of an ants' nest from a surface of the refrigerant tube in a direction of its wall thickness, wherein the refrigerant tube is a highly corrosion-resistant copper tube having a high resistance against ant nest corrosion and comprising 0.10-1.0% by weight of P and the balance consisting of Cu and inevitable impurities.
7 . The refrigerant tube according to claim 6 , comprising not lower than 0.15% by weight of P.
8 . The refrigerant tube according to claim 6 , comprising not higher than 0.8% by weight of P.
9 . The refrigerant tube according to claim 6 , comprising not higher than 0.5% by weight of P.
10 . The refrigerant tube according to claim 6 , wherein a total amount of the inevitable impurities is not higher than 0.05% by weight.
11 . A method for improving a corrosion resistance of a copper tube used in a damp environment in air-conditioning equipment or refrigerating equipment, against ant nest corrosion which is generated in the damp environment by a corrosive medium consisting of a lower carboxylic acid, and progresses from a surface of the copper tube, wherein the resistance of the copper tube against the ant nest corrosion is improved by forming the copper tube by using a material comprising 0.10-1.0% by weight of P and the balance consisting of Cu and inevitable impurities.
12 . The method for improving the corrosion resistance of the copper tube according to claim 11 , wherein the material of the copper tube comprises 0.3-1.0% by weight of P.
13 . The method for improving the corrosion resistance of the copper tube according to claim 11 , wherein a total amount of the inevitable impurities contained in the material of the copper tube is not higher than 0.05% by weight.