Gost flange standard

　　Gost flange standard is a Russia standard. The Gost No. there have GOST 12821-80 and GOST 12820-80. The first GOST NO is for butt welded weld neck flanges and the second is the slip on flanges. The pressure for GOST12821 there have 6kg to 200kg. and GOST 12820 there have 6kg to 25kg. GOST material is normally is equivalent to china material 20#,Q345 etc.