Abstract: The invention relates to a method of heat treating a cast iron having graphite particles, in particular a cast iron having graphite nodules with a substantially spherical geometry. The method comprises the step of subjecting the cast iron to a first austenitizing temperature, in order to obtain a cast iron having an austenite matrix with a substantially homogeneous carbon content. Subsequently, at least part of the cast iron is subjected to at least a second, different austenitizing temperature in order to change, in at least part of the cast iron, the carbon concentration in a part of the matrix surrounding the (spherical) geometry of the graphite particles. The method yields improved controllability on strength properties characteristics for cast irons including malleable irons, in particular for ductile iron.

Abstract: The invention relates to a method of heat treating a cast iron having graphite particles, in particular a cast iron having graphite nodules with a substantially spherical geometry. The method comprises the step of subjecting the cast iron to a first austenitizing temperature, in order to obtain a cast iron having an austenite matrix with a substantially homogeneous carbon content. Subsequently, at least part of the cast iron is subjected to at least a second, different austenitizing temperature in order to change, in at least part of the cast iron, the carbon concentration in a part of the matrix surrounding the (spherical) geometry of the graphite particles. The method yields improved controllability on strength properties characteristics for cast irons including malleable irons, in particular for ductile iron.

Abstract: The invention relates to a process for producing nodular cast iron with a high number of graphic nodules. This process comprises the following steps: preparing molten base iron for wasting castings of nodular cast iron; adding Mg to the molten base iron; inoculating the casting stream with a first inoculant when casting the cast iron into a casting mold. According to the invention, between the addition of the Mg and the inoculation of the casting stream, a preliminary inoculation using a further inoculant is carried out as an additional step. The invention also relates to a casting obtained by using this process.

Abstract: The invention relates to a process for producing nodular cast iron with a high number of graphic nodules. This process comprises the following steps: preparing molten base iron for casting castings of nodular cast iron; adding Mg to the molten base iron; inoculating the casting stream with a first inoculant when casting the cast iron into a casting mould. According to the invention, between the addition of the Mg and the inoculation of the casting stream, a preliminary inoculation using a further inoculant is carried out as an additional step.