Stainless Steel Socket Welding 4H Flanges 1.ASTM A105 and ANSI B16.5. 2.Size: 1/2" to 8" 3.stainless steel SS304 or 31 Lianfa stainless steel pipes and valves(qingyun)co.,ltd specilizes in manufacturing stainless steel pipe fittings , ball valves,sanitary fittings and valves, quick coupling,flexible fittings, flanges and carbon steel valves.