Effects of manufacturing process on residual stress in Mar-M247 alloy turbine blade

Manufacturing process of high-temperature turbine blade in heavy-duty gas turbine mainly include precision casting, grinding and other processes, while precision casting and grinding processes usually cause residual stresses in surface layer of turbine blade, affecting its service performance. In this paper, residual stress in turbine blade surface are tested and analyzed by X-ray diffraction method. Aiming at the weak diffraction effect caused by the coarse grains of Mar-M247 nickel-based alloy for high-temperature turbine blades, the diffraction parameters such as collimator diameter, exposure time and number of times were optimized and determined by analyzing diffraction peak intensity and its curve fit, so as to ensure the accuracy of the residual stress test. Based on the optimized diffraction parameters, we analyzed the difference of surface residual stress between precision casting state and grinding state, and elucidated the effects of different grinding parameters on surface residual stress of turbine blade.