CS GOST RUSSIAN STANDARD FLANGE standard:gost size:1/2"-24" ... :PN 6,PN 16,PN 10,PN 25,PN40,PN63materail:CS CT20,16Mn,SS304/304L,316/316L COATING:RUST PROOF OIL ... 12820:PLATE FLANGEGOST BLIND FLANGEGOST 12821 :WELDING NECK FLANGE STEEL/CS GOST RUSSIAN STANDARD FLANGE BLIND