Representation method of steel grade in China (III) : high quality carbon structural steel and high quality carbon spring steel

High quality carbon structural steel adopts two Arabic numerals (the average carbon content is expressed in tens of thousands) or Arabic numerals and element symbols to form a brand.

① For, rimmed steel and semi killed steel, the symbols “F” and “B” shall be added at the end of the grade respectively. For example, the grade of rimmed steel with an average carbon content of 0.08% is expressed as “08F”; The grade of semi killed steel with an average carbon content of 0.10% is expressed as “10B”.

② . killed steel (s and P ≤ 0.035% respectively) is generally not marked with symbols. For example, the designation of killed steel with an average carbon content of 0.45% is “45”.

③ For high-quality carbon structural steel with high manganese content, the symbol of manganese element shall be added after the Arabic numeral indicating the average carbon content. For example, the grade of steel with average carbon content of 0.50% and manganese content of 0.70% ~ 1.00% is “50Mn”.

④ High grade and high-quality carbon structural steel (s and P ≤ 0.030% respectively), and the symbol “A” is added after the brand. For example, the grade of high-grade high-quality carbon structural steel with an average carbon content of 0.45% is expressed as “45A”

⑤ . super grade high-quality carbon structural steel (s ≤ 0.020%, P ≤ 0.025%), add the symbol “e” after the brand. For example, the grade of super grade high-quality carbon structural steel with an average carbon content of 0.45% is expressed as “45e”.

The designation method of high-quality carbon spring steel is the same as that of high-quality carbon structural steel (65, 70, 85 and 65Mn Steel exist in GB / t1222 and GB / t699 respectively).