Method for producing piping and method for forming oxide film on inner surface of copper pipe

A method of forming an oxide film on an inner surface of a copper pipe through injecting a chloride ion-containing aqueous solution into the copper pipe to fill the copper pipe, thereby forming a copper oxide film on the inner surface of the copper pipe,

• wherein the chloride ion-containing aqueous solution is injected into the copper pipe according to a process that reduces interference on the formation of the copper oxide film from a shearing force applied to the inner surface of the copper pipe due to a flow of the chloride ion-containing aqueous solution through the copper pipe, wherein
• a content of chloride ions in the chloride ion-containing aqueous solution is not less than 50 mg/L and not more than 300 mg/L.

A method of manufacturing a pipe, the method comprising:

• an oxide film formation step of forming a copper oxide film on an inner surface of a copper pipe through injecting a chloride ion-containing aqueous solution in which a content of chloride ions is not less than 50 mg/L and not more than 300 mg/L into the copper pipe to fill the copper pipe.

A method of forming an oxide film on an inner surface of a copper pipe through injecting a chloride ion-containing aqueous solution in which a content of chloride ions is not less than 50 mg/L and not more than 300 mg/L into the copper pipe to fill the copper pipe, thereby forming a copper oxide film on the inner surface of the copper pipe.