C: 0.10 ~ 0.18 
 Si: 0 ≤ 0.15 of Mn: 0.80 ~ 1.20 P: 0.05 ~ 0.10 S: 0.23 ~ 0.33 Pb: 0.15 to 0.35 

 Tensile strength σb (MPa): (hot) 390 - 540; (cold drawn) steel thickness or diameter of 8 to 20: 530 ~ 755;> 20 to 30: 510 ~ 735;> 30: 490 ~ 685 ≥ 7.0 Reduction of area ψ (%) (%) elongation δ5: (hot) ≥ 22; (cold): (hot) ≥ 36 Hardness: (hot) ≤ 170HB; (cold-drawn steel) 152 ~ 217HB