Grinding of fir tree slots of powder metallurgy superalloy FGH96 using profiled electroplated CBN wheel

Broaching is commonly used for machining fir tree slots on turbine disk, which has outstanding advantages and disadvantages, such as high-quality machined surface, high manufacturing accuracy, and high productivity as well as fast tool wear, extremely high processing costs, long preparation time, and poor process flexibility. Utilizing the electroplated cubic boron nitride (CBN) profiled grinding wheels and single-sided local profiled grinding process, the experiments of FGH96 turbine disk slots are carried out. The results show that the high precision of slot profile can be achieved by the developed process. Using the given experimental parameters n = 48,000 rpm, a_p = 0.002 mm, v_f = 100 mm/min, and 600# electroplated CBN-profiled wheel, the profile error of FGH96 slots is within ±0.012 mm, and the grinding surface roughness is less than Ra 0.8 μm. After four whole slots are machined completely, the grinding wheel still has grinding capability, which proves that 600# electroplated CBN-profiled wheel can meet the grinding needs of FGH96 turbine disk slots.