... JIS G3454-2007, JIS GB/T ... Grade: 20#, 45#16Mn, St52, St42 Carbon steel butt welded seamless pipe ... JIS G3454-2007, JIS GB/T ... Grade: 20#, 45#16Mn, St52, St42 Carbon steel butt welded seamless pipe ... Gr.B 4: ASME B36.10 Standard: JIS, GB, DIN, ASTM, APIStandard: JIS G3454-2007, JIS G3455-2005, ... JIS G4051, S20C ,S45C, JIS G3454, JIS 3454 ,STPG42 DIN 17175 ST 45-8, ST 52 (5) Tolerate: OD :+1% / -1% WT ...