Herein, the effect of various treatment modes on the magnetic properties of amorphous alloys Fe49Ni29Si9B13 and Fe59Ni19Si9B13 obtained by melt spinning was considered. Samples from both alloys were heat-treated separately in the magnetic field and without the field. An increase in soft magnetic properties was detected during the transition to the crystalline phase (Hc = 0.63Oe, Bm = 1.55T, Br = 2.16T). It was determined that the soft magnetic properties of materials disappear with the formation of crystalline phases. The obtained materials were applied by replacing the electrical steel in the core of the LC1E2501 contactor produced by Schneider. During the operation, the result was 7% higher than the plant resource.

We consider the possibility to use an amorphous Fe–Ni–Si–B material in the core of contactors, which are widely used in connecting and disconnecting electric circuits, instead of the crystalline material of 3% electric steel. Alloys containing Fe–Ni–Si–B have been treated with the use of mechanical, thermomechanical, and magnetic fields, and the material for practical applications has been obtained. The processing modes were chosen so that a change in the performance of ferromagnetic (below the Curie temperature) alloys during the annealing could be controlled. The obtained specimens were annealed in oil at 360 ∘C in a magnetic field of 200 A/m for 200 min. The temperature mode was chosen so that the stress relaxation could occur during the annealing, and the structural changes in the material could be observed.