Feasibility study: relationship between fractal analysis of graphite and mechanical properties in gray cast iron

摘要

A feasibility study is conducted to correlate the morphologies and distributions of graphite with the mechanical properties in commercial gray cast iron. The quantitative method for examining the graphite is a combination of a fractal description of graphite shape together with an automated image analysis technique. Two parameters-fractal dimension (roughness), D, and shape factor, a-are used to numerically characterize the graphite morphologies. It is found that graphite morphologies associated with different properties (UTS values from below 30,000 psi to above 50,000 psi) can be roughly identified as separate groups in the fractal map. The measurements are very close since the samples have much less variation in properties (less than 2500 psi in tensile strength) with very similar graphite microstructures. It is also confirmed with the field measurement that the high UTS or high tensile strength is associated with the larger D values (finer graphite) and the smaller a values (shorter graphite).