A steel gear made from an AISI 1040 steel is to be surface hardened and strengthened by carburization. The gear will be put in an atmosphere-controlled furnace set at 850 degrees Celsius that has an atmosphere of 1.0 wt% carbon for a given period of time. The gear will then be taken out of the furnace and left to cool at room temperature. A design requirement of the gear design states that the tensile strength of the gear 0.3 mm below the surface must be at least 750 MPa.