Incompatible effects of B and B + Nb additions and inclusions' characteristics on the microstructures and mechanical properties of low-carbon steels

The influence of boron as well with niobium additions on the phase transformation behaviour, resultant microstructures, and mechanical properties thermomechanically controlled hot-rolled direct-quenched low-carbon bainitic steel plates was investigated. Also, probable factors that could inhibit their specific merits hardenability, behaviour properties, were studied. Continuous cooling diagrams both deformed non-deformed austenite constructed for investigated steels. Laser scanning confocal microscopy (LSCM) field emission electron (FESEM) employed to examine besides detailed analyses non-metallic inclusions using FESEM combined INCA software. Moreover, precipitates qualitatively transmission (TEM). results showed addition or led an increase in critical temperatures (AC1 AC3) covering intercritical range. decreased bainite start temperature (Bs), while lone had a slight insignificant effect Bs. While alone no hardness, ultimate tensile strength (UTS), yield (YS), elongation fracture, augmenting it marginal UTS YS. In general, without deteriorated impact toughness steel. These explained terms changes chemical composition cleanness steels considering various microstructural features i.e., prior grain size, effective coarsest size characteristics, particularly formation coarse (Fe,Cr)23(B,C)6.