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Based on fundamental research about the influence of chemical composition on rolled bar hardness, hardenability, case hardenability, cold formability, and mechanical properties, a new case hardening steel has been developed which can be cold forged without spheroidizing annealing. The steel contains boron and the Si and Mn contents are less than conventional steels. The steel shows fatigue strength equivalent to the conventional steels and better toughness and machinability.

Based on fundamental study about the toughness of hot rolled microalloyed steels, a new steel composed of 0.4 % carbon, 1.10 % manganese, 0.5 % chromium and 0.15 % vanadium was developed. The steel shows high toughness and high proof stress after well-controlled hot rolling. The newly designed steering racks for passenger cars using the steel bar have properties equivalent to the racks of conventional quenched and tempered carbon steels.