Авіаційно-космічна техніка та технологія (Aug 2021)
Election of optimal methods for cleaning blades of closed monowheels of turbopump units obtained by the additive method of direct laser powder sintering
Abstract
The creation of complex structural elements of aircraft using is promising and is widely used since such elements have several structural and technological advantages over the manufacture of parts using classical technologies. However, it requires the solution of several scientific and technical problems to obtain products of high accuracy and roughness, the development of a technological process, the development of processing modes, and sometimes the development of a new design of products. For the development of technologies in modern rocketry, improving the quality and accuracy of the production of turbines of turbopump units, an important task is to search for new and improve existing technological solutions for the manufacture of such parts with high surface quality. The work aimed to analyze the existing processing methods for parts of turbopump units with complex geometry and select the most technologically advanced one for further use in technological processes. The objective of this article is an analytical review of existing methods of surface treatment of critical parts and the selection of the most technologically advanced method for finishing the blades of a closed-type turbine (with a shroud) to reduce the roughness and improve the quality of the working surface. The object of the research is the process of machining a segment of a turbine impeller made of Inconel 718 nickel alloy (domestic analog – alloy HN45MVTJuBR), which is a key element of a turbopump unit. The blank part of the turbine monowheel type was made using 3D printing technology. As a result of the work, the optimal processing method was chosen, namely, the DryLyte dry electrochemical polishing technology, which has quite significant advantages in comparison with illogical methods. This method has been tested experimentally and is being actively implemented abroad. To introduce this DryLyte technology, it is necessary to carry out additional experiments on finishing the inner channels of small size (24 mm) using the example of interscapular channels of turbines, which will make it possible to fully assess the capabilities of the technology.
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