MUMETAL is a high permeability nickel iron alloy to be used where high permeability at flux densities well under 5000 gausses is desirable. This datasheet provides information on composition, physical properties, and tensile properties. It also includes information on corrosion resistance as well as forming, heat treating, machining, and joining. Filing Code: Ni-25. Producer or source: Allegheny Ludlum Steel Corporation. See also Alloy Digest Ni-398, December 1991.