Influence of boron on ferrite formation in copper-added spheroidal graphite cast iron

This paper reviews the original work of the authors published recently,describing the influence of B on the matrix of the Cuadded spheroidal graphite cast iron.The effect of Cu has been corrected as a ferrite formation promoter in the matrix of the grey cast iron by the usage of high-purity material.Also,this paper focuses on the ferrite formation and the observation of the Cu distribution in the B-added and B-free Cu-containing spheroidal graphite cast iron.The Cu film on the spheroidal graphite can be successfully observed in the B-free sample using a special etching method.However,in the B-added sample,no Cu film could be found,while the secondary graphite was formed on the surface of the spheroidal graphite.The interaction between B and Cu is stressed as a peculiar phenomenon by the employment of a contrast experiment of B and Mn.The heat treatment could make Cu precipitate more significantly in the eutectic cells and in the matrix in the form of large Cu particles because of the limited solubility of Cu.