A spheroidal graphite cast iron having a chemical composition of: C: 3.0% to 4.0%, Si: 2.0% to 2.4%, Cu: 0.20% to 0.50%, Mn: 0.15% to 0.35%, S: 0.005% to 0.030%, Mg: 0.03% to 0.06%, each by mass, and the balance being Fe and inevitable impurities, where Mn and Cu are contained at 0.45% to 0.75% in total; and a structure in which a ferrite layer encloses spheroidal graphite crystallized out in a matrix of pearlite. Part of the pearlite is extended from the matrix side to the spheroidal graphite side to divide the ferrite layer at one or more areas.

The present invention relates to a particulate inoculant for treating liquid cast-iron, comprising, on the one hand, support particles made of a fusible material in the liquid cast-iron, and on the other hand, surface particles made of a material that promotes the germination and the growth of graphite, disposed and distributed in a discontinuous manner at the surface of the support particles, the surface particles presenting a grain size distribution such that their diameter d50 is smaller than or equal to one-tenth of the diameter d50 of the support particles.

The present invention relates to a particulate inoculant for treating liquid cast-iron, comprising, on the one hand, support particles made of a fusible material in the liquid cast-iron, and on the other hand, surface particles made of a material that promotes the germination and the growth of graphite, disposed and distributed in a discontinuous manner at the surface of the support particles, the surface particles presenting a grain size distribution such that their diameter d50 is smaller than or equal to one-tenth of the diameter d50 of the support particles.

Methods for producing steel components with well-adhering metallic coatings that provide protection from corrosion offer flexibility in processing qualities. In one example, a flat steel product comprising a steel material that is hardenable by quenching in a hot forming operation and that has a yield point of 150-1100 MPa and a tensile strength of 300-1200 MPa may be coated electrolytically with a thin zinc layer. From the flat steel product, a blank may then be obtained that is heated directly to at least 800 C. and then formed into the steel component. Alternatively, the blank may initially be formed into the steel component and then heated to at least 800 C. Either way, the steel component may then be hardened by sufficiently rapid cooling from a sufficiently high temperature.