Magnetic measurements are suitable to determine mechanical and technical properties of a material especially steel. The magnetic and mechanical properties of a material are determined by the microstructure. The microstructure is determined by the chemical composition of a material. In the case of steel, heat treatment also has a significant influence. A targeted heat treatment adjusts technical properties such as hardness, tensile strength or elasticity. In contrast, an untargeted heat treatment produces phenomena such as grinding burn, grain coarsening or residual stresses. Measuring magnetic properties can determine the effect of heat treatment on a material.
The material is magnetized in an alternating magnetic field. An interaction of the magnetically effective components of the material with the external field takes place. According to Faraday’s law, short electrical pulses are generated by induction. The pulses are measured with a coil. The type of microstructure determines the frequency and intensity of the electrical pulses. The method and the physical effect is called Barkhausen noise (BNA). The method has been used and scientifically studied for over 100 years.