Correlation of Magnetic Properties with Mechanical Properties of a High Tensile Grade Steel in Various Heat Treated Conditions

A high tensile grade steel was soaked for 30 min in the range of soaking temperatures 800–980 °C followed by cooling through air, oil, and water with the aim to produce a wide range of microstructure and mechanical properties. Microstructural modifications were observed through optical and scanning electron microscopy. Mechanical properties were evaluated through a micro Vicker’s hardness tester and Zwick made tensile testing machine. Magnetic properties such as coercivity, remanence and maximum induction were measured through a magnetic hysteresis loop (MHL) tester; MagStar for the correlation with mechanical properties for their non-destructive evaluation. The coercivity was correlated with the mechanical properties and was found to have a strong correlation due to the common reason of obstruction of dislocations and magnetic domain wall motion on the change in microstructural modifications such as volume fraction of phase, their finer and coarser form. The results clearly showed that by monitoring coercivity through MHL, mechanical properties of steels which altered due to microstructural modifications during heat treatment of the steels could be evaluated for their precise control.