A wire for manufacturing steel wire for pearlitic structure bolt having a tensile strength of 950 to 1600 MPa, a steel wire for pearlitic structure bolt having a tensile strength of 950 to 1600 MPa, a pearlitic structure bolt, and a manufacturing method thereof

摘要

A wire for manufacturing a steel wire for pearlitic structure bolt according to the present invention having a tensile strength of 950 to 1600 MPa has a predetermined chemical composition and is subjected to isothermal transformation treatment directly after hot rolling to produce , And in the case where the C content is expressed as [C] in unit mass%, in the region from the surface of the wire to the depth of 4.5 mm, the metal structure has a pearlite structure with a surface area of 140 [C] or more , The average block particle diameter of the pearlite block measured in the cross section of the wire from the surface of the wire to a depth of 4.5 mm is not more than 20 m and a depth from the surface of the wire of 4.5 mm , The average lamella spacing of the pearlite structure is greater than 120 nm and less than or equal to 200 nm.