Abstract: A wire rod having a tensile strength of 950 to 1600 MPa for manufacturing a steel wire for a pearlite structure bolt according to the present invention includes a predetermined chemical composition and is manufactured by hot rolling and then direct isothermal transformation treating, in which when an amount of C in terms of mass % is indicated as <C>, a structure at an area from a surface of the wire rod to a depth of 4.5 mm includes 140×<C> area % or more of a pearlite structure, the average block size of a pearlite block at the area from the surface of the wire rod to the depth of 4.5 mm is 20 ?m or less, in which the average block size is measured in a transverse section of the wire rod, and the average lamellar spacing of the pearlite structure at the area from the surface of the wire rod to the depth of 4.5 mm is more than 120 nm to 200 nm.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: Provided is a wire rod contains, in mass %: C: 0.6 to 1.1%; Si: 0.1 to 0.5%; Mn: 0.2 to 0.6%; S: 0.004 to 0.015%; and, Cr: 0.02 to less than 0.05%; with a balance including Fe and inevitable impurities in which P is limited to 0.02% by mass or lower and Al is limited to 0.003% by mass or lower; the wire rod has a pearlite in a surface thereof; and, the wire rod has, in a peripheral portion in a cross section thereof, a {110} crystal plane of ferrite in the pearlite, an accumulation degree of the crystal plane being 1.2 or more.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: The present invention provides a wire rod with a composition at least including: C: 0.95-1.30 mass %; Si: 0.1-1.5 mass %; Mn: 0.1-1.0 mass %; Al: 0-0.1 mass %; Ti: 0-0.1 mass %; P: 0-0.02 mass %; S: 0-0.02 mass %; N: 10-50 ppm; O: 10-40 ppm; and a balance including Fe and inevitable impurities, wherein 97% or more of an area in a cross-section perpendicular to the longitudinal direction of the wire rod is occupied by a pearlite, and 0.5% or less of an area in a central area in the cross-section and 0.5% or less of an area in a first surface layer area in the cross-section are occupied by a pro-eutectoid cementite.

Abstract: A high-carbon steel wire rod of high ductility for steel cord and the like is provided that experiences little breakage during drawing. The high-carbon steel wire rod of high ductility is a high-carbon steel wire rod fabricated by hot rolling that that has a carbon content of 0.7 mass % or greater, wherein 95% or greater of the wire rod metallographic structure is pearlite structure and the maximum pearlite block size of pearlite at the core of the hot-rolled wire rod is 65 ?m or less. The high-carbon steel wire rod of high ductility has a tensile strength in a range of {248+980×(C mass %)}±40 MPa} and a reduction of area of {72.8?40×(C mass %) %} or greater. The high-carbon steel wire rod of high ductility is characterized in that the average pearlite block size at the core of the hot-rolled wire rod constituted by ferrite grain boundaries of an orientation difference of 9 degrees or greater as measured with an EBSP analyzer is 10 ?m or greater and 30 ?m or less.

Abstract: Provided is a wire rod contains, in mass %: C: 0.6 to 1.1%; Si: 0.1 to 0.5%; Mn: 0.2 to 0.6% ; S: 0.004 to 0.015%; and, Cr: 0.02 to less than 0.05%; with a balance including Fe and inevitable impurities in which P is limited to 0.02% by mass or lower and Al is limited to 0.003% by mass or lower; the wire rod has a pearlite in a surface thereof; and, the wire rod has, in a peripheral portion in a cross section thereof, a {110} crystal plane of ferrite in the pearlite, an accumulation degree of the crystal plane being 1.2 or more.

Abstract: A high-carbon steel wire rod of high ductility for steel cord and the like is provided that experiences little breakage during drawing. The high-carbon steel wire rod of high ductility is a high-carbon steel wire rod fabricated by hot rolling that that has a carbon content of 0.7 mass % or greater, wherein 95% or greater of the wire rod metallographic structure is pearlite structure and the maximum pearlite block size of pearlite at the core of the hot-rolled wire rod is 65 ?m or less. The high-carbon steel wire rod of high ductility has a tensile strength in a range of {248+980×(C mass %)}±40 MPa} and a reduction of area of {72.8?40×(C mass %) %} or greater. The high-carbon steel wire rod of high ductility is characterized in that the average pearlite block size at the core of the hot-rolled wire rod constituted by ferrite grain boundaries of an orientation difference of 9 degrees or greater as measured with an EBSP analyzer is 10 ?m or greater and 30 ?m or less.

Abstract: The present invention provides a high strength, high toughness steel wire rod useful for a PC steel wire, galvanized steel strands, spring use steel wire, cables for suspension bridges, etc. By hot rolling, then directly patenting or reaustenitizing, then patenting a high carbon steel wire rod of a specific chemical composition of the steel and chemical composition, size, and numerical density of inclusions, piano wire rod or high carbon steel wire rod having a structure of mainly pearlite, having an average value of the proeutectoid cementite area ratio of 5% or less in a center region of less than 20% of the wire rod diameter from the center of the wire rod, having a micromartensite size of the C section of 100 ?m or less, having a tensile strength of the 170 kgf/mm2 class or more, and having a drawing ratio at break of 30% or more is obtained.

Abstract: The present invention provides a high strength, high toughness steel wire rod useful for a PC steel wire, galvanized steel strands, spring use steel wire, cables for suspension bridges, etc. By hot rolling, then directly patenting or reaustenitizing, then patenting a high carbon steel wire rod of a specific chemical composition of the steel and chemical composition, size, and numerical density of inclusions, piano wire rod or high carbon steel wire rod having a structure of mainly pearlite, having an average value of the proeutectoid cementite area ratio of 5% or less in a center region of less than 20% of the wire rod diameter from the center of the wire rod, having a micromartensite size of the C section of 100 ?m or less, having a tensile strength of the 170 kgf/mm2 class or more, and having a drawing ratio at break of 30% or more is obtained.