Bearing races are most often manufactured from 52100 steel, (bearing quality chrome steel), which is valued for its mechanical strength, high hardness and excellent wear resistance. Hardness is typically Rockwell C 58 to 62.
Hartford’s bearing parts, particularly races, are typically manufactured from a forged blank or pipe / tube stock. The part is then machined and ground to precise ID, OD and width. Bearing races must withstand the high loading imparted by the rolling elements. This loading is theoretically a point in ball bearings and a line in roller bearings.