Detailed Product Description The perform to standard : ASTM A53, ASTM A106, ASTM A179,ASTM A513,ASTM A519, DIN 2391, DIN 2393, DIN1629, DIN17175 etc. The steel grade: ST35, ST35.8, ST37, ST37-2, ST44, ST44-2, ST45, ST45.8, ST52, ST52-3 etc. The specification range: OD20mm-OD120mm and WT1.0mm-WT12mm. Product condition: BK, BKS, BKW.