The material of wire for component thermally untreated steel wire for component thermally untreated and thermally compoente untreated and its production method

摘要

Abstract invention patent: "material of wire for component thermally untreated steel wire for component thermally untreated and thermally compoente untreated and its production method.The present invention relates to a material wire used for the production of a component thermally untreated whose resistance to traction is 900MPa the 1300mpa, containing, in mass%, C: 0.20? The 0.50? , Si: 0.05? The 2.0? Mn: 0.20? The 1.0? Being limited to contain P: 0030? Or less, s: 0030? Or less, N: 0.005? Or less, F1 is defined by expression (1), the following is less than 0.60.With the balance being made of Fe and inevitable impurities, where the metallic structure contains a pearlite structure 64? (c)? ? 52. As in a fraction of the volume, with the balance being made of one kind or two kinds of a ferrite structure and a pro eutectoide bainite structure, the average diameter of grain of pearlite structure in a region from the surface layer up to 0.1 D is 15? M or less when the diameter of the wire material is adjusted to be D, e (average diameter of grain of pearlite structure in the region from the surface layer up to 0.1 d) / (average diameter of grain of pearlite structure in a range from 0.25 d to the center) is smaller than 1.0. F1 = C (?) ? (?) ? 24. Mn (?) ? 6. (1)