A method for producing spheroidal graphite cast iron having a specific final composition includes: subjecting a molten iron to a spheroidization treatment using a spheroidizing agent of an FeSiMgCa-based alloy containing no rare earth element; conducting an inoculation treatment using a first FeSi-based inoculant; and conducting a pouring inoculation treatment with a given amount of a second FeSi-based inoculant containing 45-75% of Si, 1-3% of Ca, and 15 ppm or less of Ba.

A grade of ductile cast iron having a tensile strength (Rm) equal to or greater than 700 MPa, an elongation at break equal to or greater than 11%, a yield strength (Rp.sub.0.2) equal to or greater than 532 MPa, and a minimum ratio of yield strength (Rp.sub.0.2) to tensile strength (Rm) of 76% in a tensile test performed on a specimen taken from a tensile bar in accordance with standard EN 1563 and having a diameter of 25 mm and a length of 200 mm.

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.