The effect of various heat treatments on the magnetic behavior of the Fe-Cr-Co magnetically hard alloy

Abstract

In this research, the magnetic and structural properties of the Fe-23Cr-9Co alloy were investigated. The obtained results showed that the existence of non-magnetic phases in the casting structure or the presence of metallurgical defects in the forged structure had a destructive effect on the magnetic properties. The use of different aging methods showed that each of them had a positive effect on the magnetic properties. It was also found that isothermal aging, in the absence of the magnetic field, with the increase in aging time, was only able to enhance the coercive force to a certain extent. The maximum coercive force achieved was 16 Oe. Also, aging by the continuous cooling method increased the coercive force to 18 Oe. Further, the use of thermo-magnetic treatment produced an anisotropic magnetic effect. In this method, the coercive force was increased with raising the temperature, such that the maximum coercive force of this method was 13 Oe, as obtained at 640 °C. The use of step aging also increased the difference in the chemical composition of α1 and α2 phases, leading to an increase in the coercivity up to 105 Oe.