ELECTRIC RESISTANCE WELDED TUBE EXCELLENT IN GROOVING RESISTANCE AND ITS PRODUCTION

摘要

PROBLEM TO BE SOLVED: To provide an electric resistance welded tube having high resistance to the selective corrosion (grooving or grooving type corrosion) of the electric resistance weld zone of an electric resistance welded tube. SOLUTION: This tube is obtd. by welding a steel sheet contg. precipitates of multiple sulfides of <=5.0μm sizes composed of two phases of sulfides consisting essentially of Mn precipitated with Mg-contg. oxides as nuclei and sulfides consisting essentially of Cu and sulfides consisting essentially of Cu, or precipitates of multiple sulfides and nitrides of <=5.0μm sizes composed of two phases of sulfides consisting essentially of Mn precipitated with Mg- contg. oxides as nuclei and sulfides consisting essentially of Cu.