The Effect of Inoculation on Microstructure and Mechanical Properties of Ductile Iron

Abstract

The current work proposes thermal analysis system for analysis of ductile iron solidification processing. The system consists of standard pouring cup with built in thermocouple. The thermocouple is connected to data logger system so as to store temperature data of solidification sequence. The ductile iron treatment consists of composition control, melt pre-treatment, magnesium treatment and inoculation processing. Even small change in processing can be monitored by thermal analysis and its effects on final microstructure and mechanical properties were studied. Along with test cups, the tensile test bars were also poured and analyzed for correlating the mechanical properties with solidification sequencing. The melting trials with varying amount of inoculation processing were conducted to study its effect especially on amount of nodule count, nodularity and amount of pearlite and ferrite phase. As the microstructure decides the final mechanical properties in ductile iron castings, the nucleation and proportion of these phases is of paramount importance during solidification. The thermal analysis of base metal and inoculated material can be effectively used for improving mechanical properties of ductile iron castings.