Drilling performance of green austempered ductile iron (ADI) grade produced by novel manufacturing technology

摘要

Machinability study on drilling of green austempered ductile iron (ADI) grade was conducted using a TiAlN-coated tungsten carbide drill. The green ADI grade was produced by a novel manufacturing technology known as continuous casting-heat treatment technology to save energy and time in foundry. However, in spite of good combination of strength, toughness and enhanced wear resistance, the microstructural properties of ADI sometimes lead to machinability issues. The effect of cutting parameters on cutting force coefficients, chip morphology, and surface integrity of the drilled surface were discussed. Results showed that the strength properties of novel ADI are comparable to that of ASTM grade 1 ADI, whereas percent elongation is comparable to that of ASTM grade 2 ADI. Results obtained also showed that the combined effect of cutting speed at its higher values and feed rate at its lower values can result in increasing cutting force coefficients and specific cutting energy. At higher cutting speed, hardness values increases at the subsurface layer of the drilled surface due to plastic deformation.