Prospects for using carbonitride-forming elements in carbon steels to increase their mechanical properties

The effect of carbonitride-forming elements on the structure and mechanical properties of a carbon steel (0.65% C) is studied. A thermodynamic calculation is applied to plot solubility curves for the carbides and nitrides of titanium, aluminum, niobium, and vanadium. The optimum concentrations of these elements are determined to form dispersed carbide and nitride particles of the required number and sizes to impede austenite grain growth. Data on the effect of additions of various carbonitride-forming elements on the austenite grain growth and the impact strength are received. The intrduciton of carbonitride-forming elements in carbon steel in certain combinations and concentrations is shown to improve its mechanical properties.