Development of spheroidizing annealing regime for boron-containing steel

A problem of deep 'softening' up to required hardness equal to 20-25 HRC (for improving cutting machinability) and reliable reproducibility of mechanical properties of B-containing stamping die steel of cold deformation is considered. The conditions of spheroidizing annealing, providing the required hardness and mechanical properties of steel, are elaborated. It is ascertained that the optimum hardness is being achieved at 855°C with holding for 1.8 h. The most mature spheroidization of pearlite is observed at same temperature.