Abstract: A drawn steel wire has a predetermined chemical composition; in a region of the drawn steel wire that is closer to an axis line than a depth of 100 ?m from a surface of the drawn steel wire in a lengthwise-section that includes the axis line of the drawn steel wire, a metallographic structure includes 90% or more of a drawn pearlite by an area ratio; in a region of the drawn steel wire that is the depth of 100 ?m from the surface of the drawn steel wire in the lengthwise-section, the metallographic structure includes 70% or more of the drawn pearlite by the area ratio; when D in units of millimeters represents a diameter of the drawn steel wire, ?HV represents a standard deviation of a Vickers hardness of the surface of the drawn steel wire, and Rp0.2 represents a yield strength of the drawn steel wire, ?HV<(?9500×ln(D)+30000) exp(?0.003×Rp0.2) is satisfied, and a tensile strength TS of the drawn steel wire is 1770 MPa or higher.

Abstract: A wire rod according to an aspect of the present invention has a predetermined chemical composition, a solute N is 0.0015% or less, a structure in an area from a surface of the wire rod to a depth of ¼ of a diameter of the wire rod in a cross section thereof includes 90.0 area % or more of pearlite, and 0 to 10.0 area % in total of bainite and ferrite, a total amount of martensite and cementite in the area from the surface of the wire rod to the depth of ¼ of the diameter of the wire rod is limited to 2.0 area % or less, and the calculated maximum size of TiN-type inclusions in a surface layer area of the wire rod is 50 ?m or less.

Abstract: A high-strength flat steel wire contains, by mass %: C: 0.25 to 0.60%; Si: greater than 0.50% and less than 2.0%; Mn: 0.20 to 1.50%; S: 0.015% or less; P: 0.015% or less; Cr: 0.005 to 1.50%; Al: 0.005 to 0.080%; N: 0.0020 to 0.0080%; and one or two of Ca: 0 to 0.0050% and Mg: 0 to 0.0050% to satisfy [Ca]+[Mg]>0.20×[S], with the balance composed of Fe and impurities, the high-strength flat steel wire has tensile strength of 1000 MPa or more, an average value of Hv hardness measured in a cross section perpendicular to a longitudinal direction of 320 or more and less than 450, a standard deviation ?Hv of the measured value of 15 or less, and a width/thickness ratio of not less than 1.5 nor more than 10. [Ca], [Mg], and [S] represent contents of respective elements by mass %.

Abstract: A wire rod according to an aspect of the present invention has a predetermined chemical composition, a solute N is 0.0015% or less, a structure in an area from a surface of the wire rod to a depth of ¼ of a diameter of the wire rod in a cross section thereof includes 90.0 area % or more of pearlite, and 0 to 10.0 area % in total of bainite and ferrite, a total amount of martensite and cementite in the area from the surface of the wire rod to the depth of ¼ of the diameter of the wire rod is limited to 2.0 area % or less, and the calculated maximum size of TiN-type inclusions in a surface layer area of the wire rod is 50 ?m or less.

Abstract: A high strength wire rod in which an area fraction of pro-eutectoid ferrite is 3% or less and an area fraction of pearlite structure is 90% or more, being obtained by subjecting a hard steel wire rod having specified composition to a molten salt patenting treatment directly after hot-rolling or after performing re-austenitization subsequent to hot-rolling.

Abstract: A wire rod which is mainly composed of pearlite and has an area fraction of 5% or less of a non-pearlite structure composed of pro-eutectoid ferrite, degenerate-pearlite or bainite in a section, or has an area fraction of 10% or less of a non-pearlite structure in a portion from the surface to a depth of 100 ?m.

Abstract: A high strength wire rod in which an area fraction of pro-eutectoid ferrite is 3% or less and an area fraction of pearlite structure is 90% or more, being obtained by subjecting a hard steel wire rod having specified composition to a molten salt patenting treatment directly after hot-rolling or after performing re-austenitization subsequent to hot-rolling.

Abstract: A wire rod which is mainly composed of pearlite and has an area fraction of 5% or less of a non-pearlite structure composed of pro-eutectoid ferrite, degenerate-pearlite or bainite in a section, or has an area fraction of 10% or less of a non-pearlite structure in a portion from the surface to a depth of 100 ?m.