A nodular cast alloy, a casting made therefrom, and a production process therefor, which has a perlitic-ferritic microstructure for cast iron products and has a high strength combined with good ductility and toughness even in the cast state, including, as nonferrous constituents, C, Si, Ni, Mn, Cu, Mg, Cr, Al, P, S and normal impurities, characterized in that the nodular cast alloy in the cast state without subsequent heat treatment achieves a high static strength of a 0.2% offset yield strength of 600 MPa and a tensile strength of 750 MPa combined with good ductility of an elongation at break A5 of from 2 to 10%.

A nodular cast alloy, a casting made therefrom, and a production process therefor, which has a perlitic-ferritic microstructure for cast iron products and has a high strength combined with good ductility and toughness even in the cast state, including, as nonferrous constituents, C, Si, Ni, Mn, Cu, Mg, Cr, Al, P, S and normal impurities, characterized in that the nodular cast alloy in the cast state without subsequent heat treatment achieves a high static strength of a 0.2% offset yield strength of 600 MPa and a tensile strength of 750 MPa combined with good ductility of an elongation at break A5 of from 2 to 10%.

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.

The invention relates to ferritic cast iron comprising spheroidal graphite, containing, in % by mass, from 3.4 to 3.8% of carbon (C) from 1.5 to 2.1% of silicon (Si) not more than 0.25% of manganese (Mn) not more than 0.05% of sulfur (S) up to 0.6% of usual accompanying elements balance iron (Fe)

In order to achieve a notched impact energy of at least 20 J at a temperature of 10 C. in the case of such a ferritic cast iron comprising spheroidal graphite, the invention proposes that the accompanying elements chromium (Cr), vanadium (V), niobium (Nb) and titanium (Ti) in total be limited to 0.05% by mass. This results in a graphite nodule count of less than or equal to 160/mm.sup.2 in this cast iron. The invention further relates to the use of such a cast iron for cold-sensitive components, in particular in ships or wind power plants.

The invention relates to ferritic cast iron comprising spheroidal graphite, containing, in % by mass, from 3.4 to 3.8% of carbon (C) from 1.5 to 2.1% of silicon (Si) not more than 0.25% of manganese (Mn) not more than 0.05% of sulfur (S) up to 0.6% of usual accompanying elements balance iron (Fe)

In order to achieve a notched impact energy of at least 20 J at a temperature of 10 C. in the case of such a ferritic cast iron comprising spheroidal graphite, the invention proposes that the accompanying elements chromium (Cr), vanadium (V), niobium (Nb) and titanium (Ti) in total be limited to 0.05% by mass. This results in a graphite nodule count of less than or equal to 160/mm.sup.2 in this cast iron. The invention further relates to the use of such a cast iron for cold-sensitive components, in particular in ships or wind power plants.

A spheroidal graphite cast iron for a component of an engine exhaust system includes carbon ranging from about 3.0 wt % to about 3.4 wt %, silicon ranging from about 4.2 wt % to about 4.5 wt %, manganese ranging from about 0.1 wt % to about 0.3 wt %, sulfur ranging from about 0.002 wt % to about 0.01 wt %, phosphorous in a range equal to or less than about 0.05 wt %, magnesium ranging from about 0.035 wt % to about 0.055 wt %, molybdenum ranging from about 0.9 wt % to about 1.2 wt %, nickel ranging from about 0.2 wt % to about 0.5 wt %, vanadium ranging from about 0.4 wt % to about 0.6 wt %, niobium ranging from about 0.1 wt % to about 0.4 wt %, cerium ranging from about 0.005 wt % to about 0.01 wt %, aluminum ranging from about 0.003 wt % to about 0.007 wt %, and a remainder of iron.

A spheroidal graphite cast iron for a component of an engine exhaust system includes carbon ranging from about 3.0 wt % to about 3.4 wt %, silicon ranging from about 4.2 wt % to about 4.5 wt %, manganese ranging from about 0.1 wt % to about 0.3 wt %, sulfur ranging from about 0.002 wt % to about 0.01 wt %, phosphorous in a range equal to or less than about 0.05 wt %, magnesium ranging from about 0.035 wt % to about 0.055 wt %, molybdenum ranging from about 0.9 wt % to about 1.2 wt %, nickel ranging from about 0.2 wt % to about 0.5 wt %, vanadium ranging from about 0.4 wt % to about 0.6 wt %, niobium ranging from about 0.1 wt % to about 0.4 wt %, cerium ranging from about 0.005 wt % to about 0.01 wt %, aluminum ranging from about 0.003 wt % to about 0.007 wt %, and a remainder of iron.

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 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 %.