A method of repairing defect in cast iron workpiece, including: machining the workpiece in the area of the defect to remove the defective material and form a chamber opening at a surface of the workpiece; anchoring a receptacle to the workpiece above the chamber (2), the receptacle is provided with an orifice in communication with the chamber; adding molten iron (4) into the receptacle so that it at least part of it flows into the chamber; adding slagging agent (5) into the receptacle; heating the slagging agent and the molten iron with an electrode (6); adding nodulizing agent into the molten iron so as to segregate graphite; and allowing the molten iron and the workpiece to cool down slowly. The above-described technique also has applicability for connecting two cast iron workpieces (11,12) together.

A method of repairing defect in cast iron workpiece, including: machining the workpiece in the area of the defect to remove the defective material and form a chamber opening at a surface of the workpiece; anchoring a receptacle to the workpiece above the chamber (2), the receptacle is provided with an orifice in communication with the chamber; adding molten iron (4) into the receptacle so that it at least part of it flows into the chamber; adding slagging agent (5) into the receptacle; heating the slagging agent and the molten iron with an electrode (6); adding nodulizing agent into the molten iron so as to segregate graphite; and allowing the molten iron and the workpiece to cool down slowly. The above-described technique also has applicability for connecting two cast iron workpieces (11,12) together.

A spheroidal graphite cast iron meeting N.sub.(5-)250, N.sub.(5-20)/N.sub.(5-)0.6, and N.sub.(30-)/N.sub.(5-)0.2, wherein N.sub.(5-) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 5 m or more, N.sub.(5-20) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 5 m or more and less than 20 m, and N.sub.(30-) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 30 m or more, among graphite particles observed in an arbitrary cross section of at least 1 mm.sup.2.

A spheroidal graphite cast iron meeting N.sub.(5-)250, N.sub.(5-20)/N.sub.(5-)0.6, and N.sub.(30-)/N.sub.(5-)0.2, wherein N.sub.(5-) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 5 m or more, N.sub.(5-20) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 5 m or more and less than 20 m, and N.sub.(30-) represents the number (/mm.sup.2) of graphite particles having equivalent-circle diameters of 30 m or more, among graphite particles observed in an arbitrary cross section of at least 1 mm.sup.2.

This invention relates to a vermicular cast iron alloy with high mechanical strength and thermal conductivity requirements to replace the conventional gray and vermicular cast irons and introduces a manufacturing process for high mechanical strength and thermal conductivity vermicular cast iron alloy and internal combustion engine parts produced from said alloy. The alloy includes carbon, manganese, tin, copper, molybdenum, silicon, magnesium, rare earths, chromium, titanium, niobium, vanadium, tungsten, phosphorus, sulfur, aluminum, and nickel. The alloy has a graphite microstructure consisting of up to 70% of vermicular particles and up to 30% of nodular particles in area, with a matrix in area up to 80% pearlitic and up to 20% ferritic, with presence of segregating carbides of up to 1%.

This invention relates to a vermicular cast iron alloy with high mechanical strength and thermal conductivity requirements to replace the conventional gray and vermicular cast irons and introduces a manufacturing process for high mechanical strength and thermal conductivity vermicular cast iron alloy and internal combustion engine parts produced from said alloy. The alloy includes carbon, manganese, tin, copper, molybdenum, silicon, magnesium, rare earths, chromium, titanium, niobium, vanadium, tungsten, phosphorus, sulfur, aluminum, and nickel. The alloy has a graphite microstructure consisting of up to 70% of vermicular particles and up to 30% of nodular particles in area, with a matrix in area up to 80% pearlitic and up to 20% ferritic, with presence of segregating carbides of up to 1%.