A method for the production of cast iron starting from pre-reduced iron ore (DRI) with an electric arc furnace includes the steps of preparing a charge of pre-reduced iron ore DRI having a metallization higher than 90% and containing over 2.8% by weight of carbon, wherein at least 80% of the carbon is combined with the iron to form iron carbide Fe.sub.3C; charging the charge of pre-reduced iron ore into the electric arc furnace; and melting the DRI charge to form liquid cast iron having at least 80% by weight of actual carbon content deriving from the carbon in the charge of pre-reduced iron ore, the melting step being in a reducing atmosphere and in a melting chamber of the electric arc furnace subjected to a positive internal pressure generated by the gases produced by reduction reactions that develop during melting.

A method for the production of cast iron starting from pre-reduced iron ore (DRI) with an electric arc furnace includes the steps of preparing a charge of pre-reduced iron ore DRI having a metallization higher than 90% and containing over 2.8% by weight of carbon, wherein at least 80% of the carbon is combined with the iron to form iron carbide Fe.sub.3C; charging the charge of pre-reduced iron ore into the electric arc furnace; and melting the DRI charge to form liquid cast iron having at least 80% by weight of actual carbon content deriving from the carbon in the charge of pre-reduced iron ore, the melting step being in a reducing atmosphere and in a melting chamber of the electric arc furnace subjected to a positive internal pressure generated by the gases produced by reduction reactions that develop during melting.

A high-strength, high-damping-capacity cast iron having both a high strength and high vibration damping capacity is provided. The high-strength, high-damping-capacity cast iron is obtained by a method including performing a graphite spheroidizing treatment on a molten metal, and consists of 2% to 4% of C, 1% to 5% of Si, 0.2% to 0.9% of Mn, 0.1% or less of P, 0.1% or less of S, 3% to 7% of Al, 0% to 1% of Sb, 0% to 0.5% of Sn, 0.02% to 0.10% of Mg, 01% to 0.5% of RE (Ce, La), Fe as balance, and unavoidable impurity.

A high-strength, high-damping-capacity cast iron having both a high strength and high vibration damping capacity is provided. The high-strength, high-damping-capacity cast iron is obtained by a method including performing a graphite spheroidizing treatment on a molten metal, and consists of 2% to 4% of C, 1% to 5% of Si, 0.2% to 0.9% of Mn, 0.1% or less of P, 0.1% or less of S, 3% to 7% of Al, 0% to 1% of Sb, 0% to 0.5% of Sn, 0.02% to 0.10% of Mg, 01% to 0.5% of RE (Ce, La), Fe as balance, and unavoidable impurity.

A method for forming an austempered iron composition with a nanoscale microstructure includes a step of heating an iron-carbon-silicon alloy with silicon to a first temperature that is lower than A1 for the iron-carbon-silicon alloy. The iron-carbon-silicon alloy is then adiabatically deformed such that the temperature of the iron-carbon-silicon alloy rises to a second temperature which is sufficient to form proeutectoid ferrite and austenite. The iron-carbon-silicon alloy is cooled to a first austempering temperature. The iron-carbon-silicon alloy is then heated to a second austempering temperature that is greater than the first austempering temperature to form a dual phase microstructure. Characteristically, the dual phase microstructure includes proeutectoid ferrite and ausferrite.

A method for forming an austempered iron composition with a nanoscale microstructure includes a step of heating an iron-carbon-silicon alloy with silicon to a first temperature that is lower than A1 for the iron-carbon-silicon alloy. The iron-carbon-silicon alloy is then adiabatically deformed such that the temperature of the iron-carbon-silicon alloy rises to a second temperature which is sufficient to form proeutectoid ferrite and austenite. The iron-carbon-silicon alloy is cooled to a first austempering temperature. The iron-carbon-silicon alloy is then heated to a second austempering temperature that is greater than the first austempering temperature to form a dual phase microstructure. Characteristically, the dual phase microstructure includes proeutectoid ferrite and ausferrite.

A method for treating molten cast iron includes, performing an inoculation treatment to the molten cast iron, with the use of an inoculant containing: 15 to 80 wt % Si; either 80 to 100 wt % purity La or 80 to 100 wt % purity Ce as RE; Ca; Al; and the balance Fe with inevitable impurities, by adding the inoculant to the molten cast iron such that: the addition amount of La or Ce relative to the molten cast iron is 0.001 to 0.009 wt %; the addition amount of Ca relative to the molten cast iron is 0.001 to 0.02 wt %; and the addition amount of Al relative to the molten cast iron is 0.001 to 0.02 wt %.

A casting of a white cast iron alloy and a method of producing the casting are disclosed. A white cast alloy is also disclosed. The casting has a solution treated microstructure that comprises a ferrous matrix of retained austenite and chromium carbides dispersed in the matrix, with the carbides comprising 15 to 60% volume fraction of the alloy. The matrix composition comprises: manganese: 8 to 20 wt %; carbon: 0.8 to 1.5 wt %; chromium: 5 to 15 wt %; and iron: balance (including incidental impurities).

A casting of a white cast iron alloy and a method of producing the casting are disclosed. A white cast alloy is also disclosed. The casting has a solution treated microstructure that comprises a ferrous matrix of retained austenite and chromium carbides dispersed in the matrix, with the carbides comprising 15 to 60% volume fraction of the alloy. The matrix composition comprises: manganese: 8 to 20 wt %; carbon: 0.8 to 1.5 wt %; chromium: 5 to 15 wt %; and iron: balance (including incidental impurities).

A highly impact resistant ductile iron casting is made from a specified high nickel content ductile iron composition and post-treated with a specified heating and cooling profile to achieve an elongation exceeding the ASTM A536 (60-40-18) standard, and meeting or exceeding Charpy V Notch impact resistance at 20 F. of greater than 11.0 ft.lbs.