A method of manufacturing cast products which are cast in a single-piece structure having an inhomogeneous graphite structure

摘要

The invention relates to a method for manufacturing a single-piece cast product having an inhomogeneous distribution of the graphite crystals in vermicular and nodular form in different parts of the finished cast product. This is achieved by adjusting the composition and physical properties of the melt or the local nucleating potential, so that the melt, in dependence on solidification time and/or the local nucleating potential, will solidify with a larger proportion of vermicular graphite crystals in those parts of the casting in which a vermicular structure is desired. In those parts in which a higher proportion of nodular graphite crystals is desired at a correspondingly smaller proportion of vermicular graphite crystals in those parts where a nodular graphite structure is desired by adjusting the local nucleation potential, it is ensured that heat is transported more rapidly away from the casting during solidification, either by providing the casting with thin sections or by placing heat-absorbing elements in the mould. The method is particularly suited for the manufacture of engine parts and power transmission parts of automotive vehicles.