The GH4169 superalloy has high strength at high temperatures. Cooling conditions have a major impact on the machined surface integrity, which further affects the fatigue properties of specimens of the GH4169 superalloy. The influence of cooling conditions on the surface integrity of the GH4169 superalloy is first studied during the side milling. Then, the effect of surface integrity under different cooling conditions on the fatigue behavior of specimens of the GH4169 superalloy is investigated by a standard tensile and tensile–mode fatigue testing. The results obtained show that surface roughness and the depth of the plastic deformation layer in wet milling and dry milling makes little difference, the surface microhardness rate in dry milling is slightly lower than that in wet milling, the surface tensile residual stress in dry milling is significantly higher than that in wet milling, and the fatigue behavior in dry milling is only about 50% of that in wet milling. In addition, the crack initiation of specimens of the GH4169 superalloy utilizing wet milling is on the subsurface, while that from dry milling is on the surface. Thus, cooling conditions have an important impact on the fatigue behavior of specimens of the GH4169 superalloy, and micro defects in dry milling are the main factors of decreasing of fatigue behavior of specimens of the GH4169 superalloy.

There is less research on vertical sculptured grinding technology. Especially in high vertical surface grinding process with the cup abrasive wheel, the thermal damage is prone to happen and undermine the grinding surface integrity. This problem limits to improve the grinding efficiency and the grinding ratio greatly. Through the analysis of vertical surface grinding process and features in depth, this paper revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel. Based on the previous research achievements, the grinding experiments on TC4 (Ti-6Al-4V) and GH4169 are carried out utilizing the self-inhaling internal cooling wheel. The experimental results show that the self-inhaling internal cooling wheel can efficiently reduce the grinding surface temperature. Moreover, the inherent mechanism of reducing the grinding temperature using the internal cooling method is revealed. Meanwhile, under the same grinding conditions, the grinding ratio during the experiments on GH4169 using self-inhaling internal cooling method is about 3 times as high as using conventional external cooling method. And the grinding forces can be reduced by about 20%. This research revealed the inherent mechanism of higher grinding temperature in the process of vertical sculptured grinding using the cup wheel, which provides theoretical basis for the design and application of self-inhaling internal cooling wheel. At the same time, an efficient and non-invasive surface grinding method of TC4 and GH4169 is presented.

An aero-engine blade is the typical thin-walled workpiece with low rigidity. The machining accuracy of the aero-engine blade with sculptured surfaces has been a research focus in the aviation industry. This article presents a new cantilever grinding process for the high precision machining of aero-engine blade. Only one end of a blade is fixed and the other end is free in order to eliminate the deformation of blade caused by over-positioning. Moreover, the vibration of aero-engine blade can be reduced so that the surface quality of blade can be improved in the grinding. The grinding parameters are optimized for the low deflections of blade. The types of tool path are also discussed in this article. Finally, the computer numerical control machining examples are implemented. The measurement results show that the profile errors of suction/pressure surface machined by the proposed process do not exceed 0.02 mm. And the machining accuracy of leading/trailing edge with a radius of about 0.05 mm is acceptable.