What types of material can I order an insert flange in?

Almost any metal material that can be machined can be made into insert flanges. The most common material for an insert is domestic dual certified 304/304L and 316/316L, and for a flange it is domestic A-105 and 515/516 Grade 70 carbon steel. However, we also regularly make insert flanges out of Alloy 20, Duplex Alloys, Nickel Alloys such as various grades of Hastelloy (C276, C22), and Aluminum.