To improve the magnetic characteristics of armco-iron, such as magnetic permeability and coercive force, samples were processed in conditions of self-propagating high-temperature synthesis. Heating was carried out to a temperature of 900 ° C, followed by isothermal holding and cooling at various speeds. The study of the microstructure of samples with a carbon content of up to 0.015% showed that grain boundaries are formed, which are divided into three unidirectional sections. Areas are established where both ends of the boundary enter triple joints with opposite angles exceeding 170 or quadruple joints are observed. Due to the non-stationary stage of the SHS process, a fine-grained structure is formed, which leads to an increase in the coercive force from 0.97 A / cm to 1.65 A / cm and, accordingly, to an increase in hardness from 95 to 157 HB.