Implementing laser pulse buildup for gte turbine rotor blades reconditioning process design development

Аuthors

Klimov V. G.

Samara State Technical University, SSTU, 244, Molodogvardeyskaya str., Samara, 443100, Russia

e-mail: vadim3945@yandex.ru, v.klimov@uecrus.com

Abstract

The gas turbine engine advancement goes hand in hand with the development of its basic component, namely, gas turbine as the key source of efficiency enhancement of the engine in aggregate. With each turn of gas turbine development, materials and technologies used for its manufacturing became more and more complicated and, as a consequence, expensive. Russia is one of global manufacturers of gas turbine engines.

The cost of engines for aviation and power industry applications is considerably high. Thus, on this background its reduction remains the main criterion of manufacturer's competiveness on the market. Besides, we should bear in mind that the gas turbine engines maintenance costs in the course of the engine life might exceed its original cost. Without effective maintenance technologies, manufacturing would incur permanent losses. One of the basic specifics of gas turbine engines consists in their significantly high production costs of a number of their parts and subassemblies with relatively short lifetime, requiring permanent replacement. Rotor blades present precisely these parts. They can be damaged by a great number of factors from changes in the structure to loss of geometry. The latter is the most frequent factor even in the case of insignificant geometry loss. From the maintenance technologies viewpoint turbine blades restoration is the most cost-effective, compared to the other parts of the engine. But the complexity of this task remains the major obstacle to its realization.

This article discusses the possibility of using high-temperature solder powders as wear-resistant layers applied by laser pulse buildup, as an alternative to classic wear-resistant composites with tungsten carbide admixture. These materials are undergoing testing for further pen height recovery on the example of the turbine blade of the turboprop starter for NK-12MP aircraft engine, and attaching wear-resistant to its end edge. Based on the conducted studies with Tescan VEGA3 LM electron microscope and Hardness DuraScan-10 micro-hardness meter, together with local abrasive wear tests and various powder materials, such as VPr11-40N, VPr24, VPr27 Rock-Dur 6740, analysis while pulse laser powder buildup, the authors confirmed the applicability of several solder powders as wear-resistant layers for turbine blades contact surfaces recovery. Further, comparative studies of the basic material, soldered and built-up structures of VPr11-40N (having the best figures) solder were conducted to detect hardening wear-resistant phases. The cooling rate dependencies of shaping and VPr11-40N solder strengthening phase size were revealed.

Keywords:

laser buildup, self-fluxing solders, powder bath, micro-hardness, electron microscopy, local abrasive wear

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