Surface integrity analysis of grinding on ductile iron

Ductile iron (DI) is a widely used material and one of the most largely casts produced. Advances in the understanding of the characteristics and behavior of this material have led to the development of parts with dimensions and shapes close to the final ones, and components with different thickness sections, including thin wall. When certain tolerances of shape and dimension have to be met, an appropriate machining process such as grinding must be chosen. This type of process produces high local efforts and hence a great amount of heat in the contact zone. Nowadays, there is scarce information on the effects of grinding on the surface integrity of DI. A comparative study of the surface finish and surface integrity of DI with different microstructures and nodule counts (NC) under grinding conditions was performed. All ground surfaces exhibited a good finish, and their surface roughness was within the expected range for grinding operations. Microstructure alterations as well as strains were studied and related to hardness alterations. The role played by mechanical and thermal effects on residual stress profiles was analyzed. A clear relationship between distortion and residual stress formation during the grinding process was established.