The chemical composition of DIN 2391 ST 35 steel includes carbon (C) 0.17-0.24%, silicon (Si) 0.10-0.35%, manganese (Mn) 0.40-0.80%, phosphorus (P) max 0.025%, sulfur (S) max 0.025%, and iron (Fe) as the remaining balance. It is a low carbon steel commonly used in manufacturing hydraulic cylinders, automotive parts, and other precision applications due to its good machinability and tight dimensional tolerances.