An insert flange is a two-piece flange, similar in concept to a lap-joint and stub-end flange, but of superior quality. It consists of an insert (usually made out of 316/316L or 304/304L), and a flange, or bolting ring (usually made out of A-105 or 515/516 Grade 70 carbon steel). These types of flanges have been used successfully in the PVF industry for over 75 years. American Insert Flange (AIF) makes a line of insert flanges for single piping applications as well a line for jacketed piping applications. See our Product Page to learn more about insert flanges and for more illustrations.