HIGH-CARBON ULTRAFINE STEEL WIRE WITH HIGH STRENGTH AND HIGH DUCTILITY, AND WIRE ROD

摘要

PROBLEM TO BE SOLVED: To provide a steel wire for a cord used as a reinforcing material for a tire particularly a high-carbon ultrafine steel wire having excellent ductility and high strength, and a hot rolled wire rod as a raw material therefor. SOLUTION: In the high-carbon ultrafine steel wire with high strength and high ductility: the difference between the tensile strength after a lapse of one week after wire drawing and the tensile strength directly after wire drawing is 50 to <350 MPa; wire diameter is <=0.4 mm; and the tensile strength after a lapse of one week after wire drawing satisfies inequality (tensile strength) (MPa)>=3450-1500×log(do), where (do) is wire diameter (mm).