Investigation on the crystallography of reverted structure and its effect on the properties of low carbon steel

A new type of reverted structure was found to form in upper bainite steel with 0.06% C, 1.5wt% Cu and 2.0wt% Ni through annealing at the temperature between A1 and A3 (two-phase region heat treatment) with slow cooling. Tensile and charpy tests showed that the sample with reverted structure exhibited high improvement in −20°C impact toughness and slight decrease in yield strength. Microstructure observed in detail by TEM suggests that Cu …