Effect of cooling rate on microstructure and mechanical properties of gray cast iron

This paper presents the results obtained and the deductions made from a series of microstructural studies and mechanical tests involving gray cast iron which was sand cast using a variety of modules. The effect of cooling rate on the primary dendrite arm spacing (DAS), secondary dendrite arm spacing (SDAS), thickness of ferrite–cementite layer (λe) and the hardness (HB) were evaluated. Results show that the both DAS and SDAS and also λe are highly dependent on the cooling rate, and they decreases as the cooling rate increases. More attempts were also done to correlate the HB with DAS, SDAS and λe. It was found that HB increases as DAS, SDAS and λe decreases.

Research highlights▶ Dendrite Arm Spacing in the gray cast iron decreases as the cooling rate increased. ▶ Secondary Dendrite Arm Spacing in the gray cast iron decreases as the cooling rate increased. ▶ Thickness of Ferrite–Cementite Layers in the gray cast iron increased as the cooling rate increased. ▶ Hardness Brinell of gray cast iron decreases when all DAS, SDAS and landa_e are increased.