The Effects of Hot Deformation Parameters on the Size of Dynamically Recrystallized Austenite Grains of HSLA Steel

Abstract

Materials scientists are seeking to produce metals with reduced weight and dimensions while maintaining the ap­propriate mechanical properties. There are several ways to improve the internal structure of metals, such as the ultra­sound used to solidify liquid metal. The homogeneity of the grains and the uniformity of the metal structure affects its mechanical strength. This paper presents the results of investigations into the effects of hot deformation parameters in compression on the austenite grain size in the HSLA (High Strength Low Alloy) steel (0.16% C, 0.037% Nb, 0.004% Ti, 0.0098% N). The axisymmetric compression investigations were performed on cylindrical investigation speci­mens using a Gleeble 3800 thermomechanical simulator with the strain rate of 1÷15.9 s-1 and strain degree ε = 1.2. Before deformation, the research specimens were austenitized at TA = 1100÷1250 °C. The metallographic observa­tions of the primary austenite grains were conducted with an optical microscope, while the structure of dynamically recrystallized austenite, inherited by martensite, was examined by using a scanning electron microscope.