Abstract
Decarburized graphite in the matrix of cast iron was investigated to produce high-value-added cast iron. The aim was to develop new uses for cast irons. Graphite was eliminated at the surface by high temperature oxidation in air atmosphere, and the other useful materials were infiltrated into the resulting pores.
The effects of holding time (3h-36h), holding temperature (1023K-1223K), and chemical composition (C; 3.27%-4.0%, Si;2.0%-4.0%) were investigated for each graphite morphology (flake graphite, compacted graphite, spheroidal graphite). It was found that the rate of formation of porosity (due to the decomposition of graphite) in cast iron follows the diffusion law. The rate of formation of porosity in flake graphite irons was faster than other types of graphite. Flake graphite is continuous in the matrix, but spheroidal graphite is independent The continuity of the graphite morphology was found to have a remarkable effect on the rate of formation of porosity.
