... cast steel, alloy steel, stainless steel, copper, aluminum, plastic, ppc, etc.. (2)According to production methods ,divided ... type and Blind flange. d, flange sealing surface: flat, raised face,male and female, tongue and groove, rubber ring ... Surfacing / Cover welding flange 4) Flange sealing surface: flat, raised face, convex face, tongue and groove, ring joint faceFlange production standard ...