Method of producing a spheroidal graphite cast iron

摘要

Spheroidal graphite cast iron whose matrix is composed of a mixture of bainite and retained austenite, containing 250 to 800 graphite grains/mm2, and its production method comprising the steps of forming the casting, annealing the casting so as to change the matrix to ferrite, machining the casting and subjecting the casting to austempering so as to subject the casting to austenitizing and isothermal transformation.