Comparative analysis of CFG grinding of Inconel 718 using electrocorundum and sintered alumina wheels: grinding forces, surface roughness, and surface morphology

Creep-feed grinding (CFG) is a variant of grinding commonly used for the machining of difficult-to-cut materials, characterized by high material removal efficiency. A distinctive feature of CFG is the removal of a substantial material allowance at a low feed rate. One of the key factors influencing the grinding process is the type of abrasive material used. In CFG, conventional abrasives are frequently employed due to their low cost and favorable cutting properties. The most commonly used abrasives—serving as the primary constituents of grinding wheels—are electrocorundum 99A and sintered alumina SG. Therefore, an experimental study was conducted on the CFG of Inconel 718 alloy to compare the grinding process and surface integrity outcomes using two types of abrasive grains. The experiments were carried out under single-pass grinding conditions. The variable process parameter in the tests was the grinding speed. The study focused on analyzing the components of the grinding force and surface roughness parameters. Additionally, the surface morphology after grinding was examined. The study demonstrated that sintered alumina grinding wheels significantly improve creep-feed grinding performance of Inconel 718 by reducing surface roughness (Ra and Rz) by up to 30% and lowering grinding forces by approximately 10–12% compared to conventional fused alumina (99A) wheels. Only the SG wheel ensured surfaces without defect over the entire grinding distance at higher speeds (25–30 m/s), confirming its superior cutting capabilities and wear resistance. Moreover, SG wheels promoted more stable, shear-dominated material removal and generated uniform chip morphology, while electrocorundum wheels induced more severe surface defects due to thermal damage and plastic deformation.