Production of spheroidal graphite cast iron by heat treatment - an example from practice

The principles of production of spheroidal graphite cast iron by heat treatment are first outlined, including: constitutional preconditions for heat treatment; influence of silicon content, quenching temperature and quenching rate on resulting hardness; heat treatment cycle curves for the pusher type furnace in order to obtain ferritic or pearlitic microstructure of the desired hardness. This is illustrated by a practical example, namely, a 3-shift production of cast iron with lamellar and spheroidal graphite in small and medium batches with casting weights of 0,1 to 50 kgs. A flexible process technology in production of pearlitic grades of S. G. iron in as-cast condition or by annealing is outlined. The conversion of the furnace plant to a pusher type furnace and resulting operational experience is described.