A 48% Ni–Fe alloy of low coercivity and improved corrosion resistance in a cyclic damp heat test

Abstract Electric arc 30t melts, deoxidised with Mn and Si, are compared to melts additionally deoxidised with cerium. In a cyclic damp heat test the melts with Ce show better corrosion behaviour. μ 4 (DC) and H c of samples of 1.0 mm thickness after heat treatment at 1080°C vary in the same range of values for both categories of melts. After heat treatment at 1080°C or 1180°C μ 4 (50 Hz) and H c of samples of 0.2 mm thickness are impaired by 20% or more for melts with Ce. For melts with Ce the strong binding of the sulphur to the deoxidiser impedes desulphurization. With small strip thicknesses, the strong binding energy of Ce to oxygen causes additional internal oxidation during heat treatment . Both deteriorate the magnetic properties. At the larger thickness of 1.0 mm there is no noticeable internal oxidation and/or desulphurization in both categories of melt due to the strip thickness.