Dilute copper alloy material and method of manufacturing dilute copper alloy member excellent in characteristics of resistance to hydrogen embrittlement

A dilute copper alloy material consisting essentially of:

• 3 mass ppm to 12 mass ppm of S (sulfur), more than 10 mass ppm but no more than 30 mass ppm of O (oxygen), 10 mass ppm to 37 mass ppm of Ti (titanium), and balance being Cu (copper),
• wherein a semi-softening temperature of the dilute copper alloy material is not higher than 148° C.,
• wherein the Ti in a form of TiO, TiO2, TiS, and Ti—O—S is included in a crystal grain or at a crystal grain boundary of the copper,
• wherein the dilute copper alloy material is adapted to be used in an environment with presence of hydrogen,
• wherein TiO is not more than 200 nm in size, TiO2 is not more than 1000 nm in size, TiS is not more than 200 nm in size, and a compound in a form of Ti—O—S is not more than 300 nm in size,
• wherein the dilute copper alloy material is produced by casting at a copper melting temperature of not less than 1100° C. and not more than 1320° C. to make a molten metal and a hot rolling process at a temperature of not more than 880° C. at an initial roll and not less than 550° C. at a final roll, and
• wherein a conductivity of the dilute copper alloy material is at least 102% IACS (International Annealed Copper Standard).