2011 Volume 83 Issue 7 Pages 378-383
The influence of Cu on the matrix structure in cast iron was studied using high purity flake and spheroidal graphite cast irons with basic chemical composition of 3.7%C-2.0%Si. Their Cu and Mn contents were changed from 0.5% and 1.0% using pure Cu and pure Mn, and their P content was changed to 0.03% and 0.1% respectively using iron phosphide.
As expected, the Mn and P acted as pearlite forming elements, however Cu acted as ferrite forming element for the flake graphite cast iron, and as pearlite stabilized element for the spheroidal graphite cast iron. The pearlite formation mechanism of Cu was confirmed to be Cu-film formation at the surface of spheroidal graphite, through SEM observation using polished samples etched with degassing 7% HCl aqua solution for two hours. In the case of flake graphite cast iron, there was no Cu-film, and Cu acted as a ferrite forming element.
