Annealing-free high-hardenability high-strength wire rod for fastener and manufacturing method thereof

The annealing-free high-hardenability high-strength steel wire rod comprises the following chemical components in percentage by mass: 0.19 to 0.39 percent of C, less than or equal to 0.25 percent of Si, 0.6 to 1.45 percent of Mn, 0.05 to 0.99 percent of Cr, 0.010 to 0.035 percent of Al, less than or equal to 0.005 percent of S, 0.001 to 0.004 percent of B, 0.01 to 0.15 percent of Ti, 0.0005 to 0.0030 percent of O, 0.001 to 0.007 percent of N and the balance of Fe and other inevitable impurities, and the condition that Ti/N is greater than or equal to 3.5 is also required to be met at the same time; mn + Cr > = 1.10%. The hot-rolled wire rod is subjected to structure and strength control by adopting relatively low rolling temperature, spinning temperature and segmented cooling after rolling, so that the wire rod has relatively low tensile strength while having high hardenability, and can realize direct drawing deformation without annealing; the production process of the high-strength fastener is simplified, th