Simulation and Experiment of Solidification Process for Directionally Solidified Industrial Gas Turbine Hollow Blades

The effect of different process parameters on solidification of industrial gas turbine hollow blades <i>via</i> HRS (High Rate Solidification) and LMC (Liquid Metal Cooling) was studied by ProCAST software. The results show that the paste zone <i>via</i> LMC process is much narrower than that by HRS process and the shape of the S/L (solid/liquid) interface is more flat. The axial thermal gradient of the blade by LMC process is about three times higher than that by HRS process. The cooling rate of the blade is 0.3-2.00℃/s by LMC process, which is far higher than that by HRS process (0.05-0.16℃/s). In LMC process, low holding temperature can still ensure high temperature gradient and cooling rate of the blade; while in order to avoid blocking of stray grains to the initial grains at the platform of the blade, HRS process should adopt high holding temperature and lower withdrawal rate. The calculated and the measured results show that compared with the blade prepared by HRS process, the PDAS (primary dendrite arm spacing) is much finer in the blade prepared by LMC process