A Method of Improving the Life of Turbine Blades Based on Laser Double-side Shock Technology

Abstract

The invention relates to a method for improving the service life of turbine blades based on laser double-sided shock technology. Firstly, Nd:YAG pulsed lasers are used to perform equal-energy laser beam splitting; then, using flowing water as a constrained layer, the blades are impacted and strengthened at the same time by using gradient facula overlapping ratios. At the root, the fixture fixes the turbine blade, using high-energy and large-spot pulsed laser with a 90% overlap rate to impact the bottom of the blade root on both sides at the same time; The lap rate of the previous impact minus 10% is used for impacting; until the lap rate is 0, the laser shock strengthening of the blade root is completed. It makes up for the shortcomings of insufficient impact depth of mechanical shot peening, and adopts a gradual lapping rate to impact the root of the blade to make the distribution of the residual stress field smoother; adopts the laser double-sided impact method to avoid deformation and damage of the blade caused by single-sided laser impact. Simultaneous impact makes the front and back of the blade bear the same force.

Description

technical field [0001] The invention relates to a method for improving the service life of a turbine blade based on laser double-sided shock technology, and belongs to the technical fields of surface engineering technology and laser processing. Background technique [0002] Both laser shock strengthening and shot peening technology are methods to generate compressive stress on the surface of materials and refine grains, thereby improving the fatigue strength of metal components. However, the disadvantage of shot peening is that the residual stress affects the depth less. Laser shock strengthening uses short pulse (ns), high power density (>1GW / cm2) laser irradiation to induce the formation of plasma high pressure (>1GPa) shock waves, which act on the surface of the workpiece and propagate to the inside, and the material undergoes high strain rate Dynamic response, causing microstructural changes, produces residual compressive stresses in deeper thicknesses. Therefore...

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Problems solved by technology

For example, patent CN103014278A discloses a method for improving blade fatigue strength by comprehensive means, but in this method, laser shock strengthening is not aimed at the easily damaged area, that is, the blade heel, and the strengthening effect is not obvious. Large deformation of parts; patent CN103146893A discloses a method of laser shock treatment of curved surfaces, the processing of curved surfaces is adjusted according to the magnitude of the current, and the overall parts are processed, the workload is cumbersome, and there is only one processing head during work, which can only Suitable for single side processing

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