A flange is a ring of steel (forged, cut from plate, or rolled) designed to connect sections of pipe, or to join pipe to a pressure vessel, valve, pump or other integral flanged assembly. Flanges are joined to each other by bolts, and to the piping system by welding or threading (or loose when stub ends are used). Stainless steel flange simplified as SS flange, it refers to the flanges that made of stainless steel. Common material standards and Grades are ASTM A182 Grade F304/L and F316/L, with pressure ratings from Class 150, 300, 600 etc and to 2500. It used in more industries than carbon steel as stainless steel has better resistant performances on corrosion environment and always provides with a good appearance.