GOST 4543 Alloyed Construciton Steel
Gost 4543 applies to alloyed construction hot-rolled and forged gauged steel with diameter or thickness up to 250 mm, and steel with a special surface finish, used in a thermally treated condition and produced in the form of bars, strips and hanks. Regarding the standards for chemical composition this Standard applies to all other types of rolled stock, ingots, and forged and punched pieces. The indicators of technological level, established by this Standard, shall be stipulated for premium and first categories of quality. The rolled stock with standardized quality indicators shall be considered as premium category of quality.
Depending on chemical composition and properties, structural steel shall be divided into categories:
extra high quality-Ш