Study on high-speed water-based abrasive two-phase flow finishing of high-temperature alloy gas film holes
With the increasing demand for turbine gas temperature in advanced aero-engines,film hole cooling is the core technology for efficient cooling of turbine blades.The rough surface finishing of laser-processed film holes is of great significance for the cooling performance and service life of turbine blades.However,the existing common finishing methods such as abrasive flow polishing,water jet polishing,magnetic polishing,and chemical polishing have certain limitations.Based on the new high-speed water-based abrasive two-phase flow technology,the laser-processed circular film holes of DD6 nickel-based single crystal superalloy blade were explored by adjusting the grinding and polishing pressure and processing time.The port hole size,inner wall morphology and surface roughness of the film holes before and after grinding and polishing were compared and analyzed by means of metallographic microscope,scanning electron microscope,laser confocal scanning microscope and other characterization methods.The results show that the polishing pressure is the first core factor affecting the dimensional accuracy and quality of the gas film hole.If the polishing pressure is too small,the polishing effect is not obvious.If the polishing pressure is too large,it is easy to induce microcracks and spread to the interior of the matrix,which eventually leads to flake peeling or chipping,resulting in the decrease of the dimensional accuracy of the gas film hole and the quality of the inner wall.When the polishing pressure is 6 MPa and the polishing time is 90 min,the remelted layer on the inner wall of the gas film hole has been basically completely removed.The aperture expansion size is 0.024 mm,the roundness is the best,the chamfering is 0.1 mm,and the surface roughness is significantly reduced from the original hole 4.85 μm to 0.80 μm.The dimensional accuracy control and the inner wall quality improvement are ideal.
gas film holeremelted layertwo-phase flowsurface roughness
万方数据
维普
