8.8-grade non-quenched and tempered cold heading steel wire rod and manufacturing method thereof

The invention discloses a 8.8-grade non-quenched and tempered cold heading steel wire rod, which contains Fe and inevitable impurity elements, and also contains the following chemical elements in percentage by mass: 0.17 to 0.23 percent of C, 0.14 to 0.22 percent of Si, 1.2 to 1.6 percent of Mn, 0.03 to 0.1 percent of Ti, 0.03 to 0.1 percent of V and more than 0 and less than 0.005 percent of N, and the mass percentage of Ti, V and N also meets the condition that (Ti + V)/N is more than 15. In addition, the invention also discloses a manufacturing method of the 8.8-grade non-quenched and tempered cold heading steel wire rod, which comprises the following steps: (1) smelting and casting; (2) soaking, wherein the soaking temperature is 1200-1250 DEG C, and heat preservation is conducted for 24 h or above; (3) blooming and cogging; and (4) rolling the wire rod. According to the 8.8-grade non-quenched and tempered cold heading steel wire rod, the yield strength is 460-480 MPa, the tensile strength is 630-650 MPa,