The invention relates to a hot-rolled
wire rod for a cord thread with tensile strength being the 4000MPa grade. The hot-rolled
wire rod is prepared from the components in percentage by weight: 0.71 to0.75 percent of C, 0.36 to 0.40 percent of Si, 0.10 to 0.14 percent of Mn, less than or equal to 0.01 percent of P, less than or equal to 0.01 percent of S, 0.10 to 0.25 percent of Cr, and 0.0005 to0.0015 percent of B. A production method comprises the steps of
smelting through a converter; carrying out RH vacuum treatment; continuously
casting into small square ingots;
slow cooling the
ingot blanks; heating the
ingot blanks; rolling at high speed;
spinning; and
air cooling for standby use. According to the hot-rolled
wire rod for cord thread with tensile strength being the 4000MPa grade andthe production method provided by the invention, through reducing the content of carbon, improving the content of
silicon, and adopting the matched process, on the premise of ensuring the tensile strength to be larger than 4000MPa, the
diameter of a wire material reaches to 3.0 to 3.5mm, so that the fracture surface of the wire material is homogenized in structure and better in performance, gammacrystal particles are micronized, the aging during
wire drawing processing is inhibited, and the fracturing of a
cementite is inhibited; and the strength and the
wire drawing limit of the wire material are improved, the times of stranding filament break does not exceed 2 times /
ton steel, and secondary
processing by a user can be omitted and simplified, so that the production cost is reduced, andthe production efficiency is improved.