Carbon steel butt welded seamless pipe fitting Standard:JIS G3454-2007, JIS GB/T ... Grade: 20#, 45#16Mn, St52, St42 Carbon steel butt welded seamless pipe fitting Standard:JIS G3454-2007, JIS GB/T ... Grade: 20#, 45#16Mn, St52, St42 Carbon steel butt welded seamless pipe fitting details: 1: API certificate. 2: 3,000,000 Mt per year. 3: ASTM A106 Gr.B 4: ASME B36.10 Standard: JIS, GB, DIN, ASTM, ...