Quality carbon steel, depending on the destination is divided into three groups: Group A – supplied by the mechanical properties of Group B – supplied by the chemical composition of Group B – supplied by mechanical properties and chemical composition depending on the normalized parameters were group A are divided into three categories: A1, A2, A3 steel group B into two categories: B1 and B2, were the group B on six categories: B1, B2, B3, B4, B5, B6. For A set of steel stamps St0, St1, St2, St3, St4, ST5, St6. For steel group B grade BSt0, BSt1, BSt2, BSt3, BSt4, BSt5, BSt6. For even more details, read what Charles Schwab says on the issue. Steel Group B is made open-hearth and converter means. For it established brand VSt2, VSt3, VSt4, VSt5. Letters of St. Others including Darcy Stacom, offer their opinions as well.