Comparative evaluation of CBN wheels with abrasive grains of different friability applied to steel and ductile iron grinding process

The industrial market demands productivity and highest quality. Abrasion machining is a crucial point for achieving both requirements. In view of this importance, in this work, a comparative analysis is made between two wheels with different friability (low and high) in the cylindrical grinding of SAE 4340 steel and ductile iron SAE D-7003 with three feed rates (0.25, 0, 50, and 1.00 mm/min) under conventional cooling and lubrication conditions. The output parameters were average surface roughness (Ra), roundness error, wheel wear, specific energy, microhardness, and cost analysis. In a complementary way, qualitative analyzes of the surface were performed through optical microscopy, scanning electron microscopy (SEM), and confocal microscopy. It is observed that the greater ductility of the iron causes 18% rougher surfaces and less tool wear. Note that the specific energy is reduced by at least 10% with more friable wheels. On average, roundness errors are 30% lower for SAE 4340 steel, with no microstructural changes for both materials. Finally, the implementation costs for the different grinding wheels decrease with an increase in the rate of advance.