THE EFFECT OF HEAT TREATMENT ON THE MICROSTRUCTURE AND THE CORROSION PROPERTIES OF GREY CAST IRON

Abstract

Investigations were carried out to study the effect of heat treatment on the microstructures and the corrosion properties of Grey cast iron. This study was carried out to determine a suitable heat treatment process which would render Grey cast iron highly resistant to corrosion in the fluids used in paper makinq industries. The method adopted was by total immersion of the heat treated grey cast iron samples. The media of immersion consisted of wood pulp and white liquor. The most important conclusions drawn from the results obtained were that annealing process is the most suitable heat treatment for grey cast iron; the weight-loss of the samples increased with time of exposure into the corrosion media from the annealing temperature, the rate of corrosion attack increased with the cooling rate and that the microstructure consists mainly of graphite flakes and ferrite in a pearlite matrix. The graphite flakes posed a resistance to corrosion in the Cast Iron