| 摘要 |
PURPOSE:To obtain the captioned wire materials, etc. inexpensively by heating the steel of the specified composition at above the specified temperature then respectively defining rolling temperature, cooling rate down to coiling and cooling rate from coiling to bundling. CONSTITUTION:The steel of C; 0.02-0.2%, Si; 0.03-0.9%, Mn; 1-1.85%, Ti; 0.25% or under, B; 0.005% or under and dpending upon cases, further Cr; 0.4% or under and the rest Fe and Ceq; 0.55% or under is heated at above 115 deg.C. Next, the steel is rolled by making the temperature in finish rolling at 700-1050 deg.C and the cooling rate from hot rolling finishing up to coiling at 40-350 deg.C/sec. The cooling rate from coiling up to bundling is defined at 1-15 deg.C. Thereby, the captioned wire material and bar steel of tensile strength; 55kg/mm<2> or higher and reduction of area; 50% or over in the hot rolled state may be obtained. |
