A new SPD process for spheroidal cast iron

Abstract

A new severe plastic deformation (SPD) process for cast iron named cylinder covered compression (CCC) is developed by the present authors. In CCC process, specimens are embedded in a steel cylinder and hot-compressed. Then the compressed material is cut into pieces, machined out of surface layers, stacked, embedded in a cylinder and hot-compressed again. By CCC process, spheroidal cast iron has been successfully hot compressed up to 99.2% reduction in height. The shape ratio of deformed graphite, β, increases as the amount of reduction increases up to 80%, after which β changes with no relationship of the reduction. In case of 80% deformed specimens, a lamellar structure of graphite and metal matrix forms. Further deformation leads to the decrease of the thickness of graphite and the fragmentation of graphite.