The Stainless Steel we used for Flanges are ASTM SA/A 182 Stainless Steel, ... used for our Flanges:ASTM SA/A 182 F304, F304L, F316, F316L, F321, F316 Ti, Etc1.4301,1.4306,1.4401,1.4404,1.4541,1 ... .4571,EtcSUS F304, F304L, F316, F316L, F321, F316 Ti, EtcMainly Flange Standards we Produced and Supplied:1 ... F/H Flange, BS 4504 Flange5) DIN EN 1092-1 Flange 6) AS2129 Flange EN1092 ...