1,Material:Carbon Steel 2,Standard:ASME, DIN, BS, JIS, JB, GB, 3,Cert:TUV,ISO9001:2000,NK,BV DIN 2533 flangesize 1/2 ... , Estandard ASME B16.5, ASME B16.47, ASME B16.36,DIN 86341-2000, DIN2505material Carbon steel(ASTM A105, Q235,A350LF2,A350LF3 ... and China National Petroleum Corporation.We are also qualified the standard material supplier of China National Offshore Oil Corporation and China ...