... . 3.Standard:ANSI,BS,DIN,GB,ISO. 4.15--600mm. Product Description:Flange cover (HG20601, HG20622, GB/T9123, JB/T86) is ... pipeline, mainly used in pipe ends or for head use. Sealing surface type has flat, sudden face, concave-convex surface, tenon ... ring connections surface. Cover flange sealing surface:FF, RF, MFM,TG, RJProduct materials for cover flange sealing surface:Carbon Steel ASTM A105,20 ...