Sulfur-containing free-cutting cold heading steel wire rod and production method thereof

The invention discloses a sulfur-containing free-cutting cold heading steel wire rod and a production method thereof. The procedures of converter smelting, LF and RH double refining and continuous casting are adopted, and section square bloom is obtained through production; the section square bloom is subjected to the procedures of heating, rolling and cooling, and the cold heading steel wire rod can be obtained; and the section square bloom comprises the components including, by weight, 0.10-0.20% of C, 0.10-0.40% of Si, 0.60-0.90% of Mn, 0.90-1.20% of Cr, 0.10-0.30% of Mo, 0.030-0.060% of S, 0.02-0.06% of Alt, less than or equal to 0.035% of P, less than or equal to 0.40% of Cu, less than or equal to 0.010% of Ti and the balance Fe and trace impurities. By reasonably designing the solution strengthening elements such as C, Si and Mn, harmful elements such as P, Cu and Ti are reduced, the processes of LF and RH double refining and square bloom are adopted, and thus the purposes of lowering the hardness of th