Thin high-strength article of spheroidal graphite cast iron and method of producing same

A method of producing a thin high-strength article of spheroidal graphite cast iron, comprising the steps of pouring a melt having a spheroidal graphite cast iron composition into a casting mold;

• removing said casting mold by shake-out after the completion of solidification of said melt, while substantially the entire portion of the resulting cast iron product is still at a temperature of its A.sub.3 transformation point or higher;
• immediately introducing said cast iron product into a uniform temperature zone of a continuous furnace kept at a temperature of the A.sub.3 transformation point or higher, where said cast iron product is held for 30 minutes or less to decompose cementite contained in the matrix:
• and transferring said cast iron product into a cooling zone of said continuous furnace to cool said cast iron product at such a cooling speed as to achieve the ferritization of said matrix.

A thin high-strength article of spheroidal graphite case iron having graphite particles dispersed in a ferrite matrix containing 10% or less of pearlite, said article being produced by removing a cast article from a mold while substantially the entire portion of the cast article is still at a temperature of its A.sub.3 transformation point or higher, immediately holding said cast article at a temperature of the A.sub.3 transformation point or higher for about 30 minutes or less to decompose cementite contained in the matrix, and cooling said cast article at such a cooling speed as to achieve the ferritization of said matrix, whereby there are substantially no fine gaps between said graphite particles and said ferrite matrix.