Spheroidization of flat-shape carbide in mid-carbon steels can be accelerated by concurrent hot working in a rather higher range of temperature under their A_cl points. It has been shown that with the help of annealing at the same temperature 1 or 2 hours after the deformation，the carbide grains can be thickened and well-distributed by Ostwald mechanism. At the same time the deformed ferrite matrix can be recrysta11ized as a general rule.