Авіаційно-космічна техніка та технологія (Feb 2022)

Experience in implementing additive technologies during repair of GTE parts from alloy EP 648 VI (KHN50VMTYUB-VI) under conditions of serial production

  • Сергій Леонідович Чигилейчик,
  • Ігор Андрійович Петрик,
  • Олександр Володимирович Овчинников,
  • Світлана Вікторівна Кирилаха

DOI
https://doi.org/10.32620/aktt.2022.1.07
Journal volume & issue
Vol. 0, no. 1
pp. 57 – 63

Abstract

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Technology has been developed for repairing the nozzle assembly (SA) casing in the D-18T engine by additively growing the damaged part by microplasma surfacing with a powder of EP648VI (KhN50VMTYUB-VI) alloy. Traditionally, a part with such damage was rejected. The cost of replacing a damaged part with a new one is about 200 thousand hryvnias. The article discusses the equipment and features of the growing technology using the method of microplasma multilayer surfacing. Additive growth of the cut-damaged part was carried out on a STARWELD 190 H robotic installation for microplasma powder surfacing using EP648 VI alloy powders with a 63–163 micron fraction. After growing, heat treatment (aging at 700 ºС, exposure for 16 hours), mechanical processing, and quality control of the grown part were carried out. To create an evidence base to determine the possibility of installing a repaired part on the engine, a set of studies was carried out, which included the determination of the chemical composition of samples grown using a technology similar to repair, metallographic studies, and mechanical tests. As a result, it was found that the chemical composition of the deposited metal meets the requirements of the technical specifications TU 14-1-3046-97 "Bars made of heat-resistant alloy grade KhN50VMTYUB (EP648), and the microstructure of the deposited metal after heat treatment is a γ - solid solution with the presence of carbides, carbonitrides and a small amount of γ´ phase, which corresponds to the normally heat-treated state of the EP 648 VI (KhN50VMTYUB-VI) alloy and the level of mechanical properties of the grown alloy with subsequent serial heat treatment (aging at 700 ° C, holding for 16 hours) not lower than the level of the forging used at serial production of a part. The economic effect of the introduction of this technology is shown, which is more than 100 thousand hryvnias (about 23% of the cost of a new part).

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