① The grades listed in the table are of high quality steel. High quality steel, in the grade suffix A, the last digit of the unified digital code is changed to 3; Super high quality steel, in the grade suffix E, the last digit of the unified digital code is changed to 6; The rimming steel, grade suffix F, the last digit of the unified digital code is changed to 0; Semi-killed steel, grade suffix b, unified number code last digit is 1
qulity steel P≤0.035%,S≤0.035%
high qulity steel P≤0.035%,S≤0.035%
speicial high qulity steel P≤0.025%,S≤0.020%
② 08 steel with aluminum deoxidation smelting killed steel, the lower limit of manganese content is 0.25%, silicon content is not more than 0.03%, aluminum content is 0.02%~0.07%, this time the steel grade is 08Al
③ Upon agreement between supply and demand parties, 08~25 steel can be supplied as semi-killed steel with silicon content not exceeding 0.17%, with the grade designations of 08b~25b.
④ Steel produced from scrap metal may have a copper content of no more than 0.30%; the copper content in steel for hot-pressure processing should not exceed 0.20%.
⑤ The silicon content of the rimming steels which used for cold pressing shall be not more
than 0.03%.
⑥ Steel produced by oxygen converter process should have a nitrogen content of no more than 0.008%.

① For steel with a diameter or thickness of less than 25mm, heat treatment is performed on a sample blank with the same cross-section size as the finished product
② Table normalizing recommended holding time is not less than 30min, air cooling; The recommended holding time for quenching is not less than 30min，70, 80 and 85 steel oil cooling, and the other steel water cooling; The recommended holding time for tempering is not less than 1h.