Influence of Heat Treatment on the Microstructure and Hardness Property of Inoculated Grey Cast Iron

Influence of heat treatments on the hardness property of inoculated grey cast iron was investigated in this study. To this end, some inoculated grey cast iron specimens with 0.2 % ferrosilicon was produced from an automobile (as-cast) sample by casting, and the chemical compositions of both the automobile and inoculated specimen were determined. Thereafter, the specimens were subjected to annealing, normalising and tempering heat treatment processes. Microstructural characteristics and hardness property were investigated using standard procedures and equipment. Results of the findings revealed that the grain sizes and phases of the inoculated and non-inoculated specimens were influence by all the heat treatment processes considered. In addition, the average Rockwell hardness (HRA) values of the annealed, normalised and tempered specimens in inoculated and non inoculated conditions are in the respective order of 41.9 and 52.8; 43.1 and 54.6; 40.7 and 50.9, and when compared with the corresponding values of 45.9 and 58.9 for the as-cast sample, the hardness property of the inoculated and non- inoculated heat treated specimens are relatively lower