Magnetic saturation is the state reached when an increase in applied external magnetic field cannot increase the magnetisation of the material further, so the total magnetic flux density more or less levels off. (Though, magnetization continues to increase very slowly with the field due to paramagnetism.) Saturation is a characteristic of ferromagnetic and ferrimagnetic materials, such as iron, nickel, cobalt and their alloys. Different ferromagnetic materials have different saturation levels.
Saturation is typically shown on magnetization curve (hysteresis loop – axis X shows magnetic H-field in ampere per metre, while axis Y shows magnetic B-field in Tesla) Magnetic Saturation of ferromagnetic materials in order of curve profiles is sheet steel, cast steel, tungsten steel, magnet steel, cobalt and magnetite.