Carbon, the C: 0.17 to 0.25 Si Si: 0.15 ~ 0.35 Manganese Mn: 0.70 ~ 1.00 Sulfur S: 0.08 to 0.15 Phosphorus P: ≤ 0.06 

 Mechanical properties: tensile strength σb (MPa): (hot) 450 600; (cold drawn) steel thickness or diameter of 8 to 20: 570 ~ 785;> 20 to 30: 530 ~ 745;> 30: δ5 of 510 ~ 705 elongation (%): (hot) ≥ 20; (cold) ≥ 7.0 Reduction of the rate of ψ (%): (hot) ≥ 30 Hardness: (hot) ≤ 175HB; (Cold Drawn ) 167 ~ 217HB