Revealing the solidification structure of nodular iron

Abstract

The effectiveness of several metallographic techniques used to reveal the solidification structure of nodular iron has been evaluated by quantitative metallography. A colour metallography reagent, sensitive to microsegregation, provides the best results, and the correlation between the colouring and the microsegregation of some elements has been verified by microanalysis. The structure of the matrix before etching affects the results, with single-phase matrices providing better information than multiple-phase matrices. In particular, ferritic matrices give more detailed and reproducible results.