Papers by Author: W.F. Ding

Abstract: Nickel-based superalloy plays an extremely important role in gas turbine engines in aerospace industry. To understand the high and super high speed grinding mechanism of nickel-based superalloy, the single-grit grinding mechanism is needed to be investigated. Previous studies on single grit were all carried out by mean of cutting or scratching. In this work, a novel experimental set-up of single-grit grinding had been developed to meet the reality of the complex kinematic grinding process. Grooves and collected chips were investigated in grinding of a typical nickel-based alloy GH4169 with wheel speed up to 150 m/s. The groove integrity is improved by increasing the grinding speed even though the chip thickness is kept constant. The typical serrated chips were observed and the frequency of chip segmentation increases linearly with the increasing of the grinding speed. Under high and super high grinding, the thermal softening due to the high temperature in adiabatic shear zone contributes to accelerate the chip formation and leads to decrease the grinding force.

Abstract: The grinding experiments on titanium alloy Ti-6Al-4V are conducted with monolayer brazed CBN wheels which are manufactured with rare earth Lanthanum modified Ag-Cu-Ti filler. Grinding force and temperature are measured as well as the topography of wheel surface. Brazed CBN wheels fabricated with Ag-Cu-Ti filler are used for comparison. The results indicate that Lanthanum restrains spread of filler, and keeps the integrity of cutting edges, which increased the sharpness, reduced the grinding force and temperature. Meanwhile, the compounds on the surface of CBN grits are finer and compacter with the addition of Lanthanum, which improves the bonding strength of joint between filler and CBN grits. Lanthanum improves the performance of the brazed CBN wheels while grinding Ti-6Al-4V.

Abstract: Single-grain grinding test plays an important part in studying the high speed grinding mechanism of materials. In this paper, a new method and experiment system for high speed grinding test with single CBN grain are presented. In order to study the high speed grinding mechanism of TC4 alloy, the chips and grooves were obtained under different wheel speed and corresponding maximum undeformed chip thickness. Results showed that the effects of wheel speed and chip thickness on chip formation become obvious. The chips were characterized by crack and segment band feature like the cutting segmented chips of titanium alloy Ti6Al4V.