INFLUENCE OF THE WORKING ENVIRONMENT ON THE HIGH-TEMPERATURE CORROSION OF GAS TURBINE UNIT PARTS

Purpose The main objective of the work was to study the influence of the working environment on the performance of the ГТК-10I hollow working blades. Research methods. Microstructure studies were carried out on microsections under a “Neophot-2” microscope and a “Stereoscan” microscope-analyzer. Microhardness was measured with a ПМТ-5 device. Phase composition and lattice periods of the main components were measured on a ДРОН-1 diffractometer in copper Kα radiation. The content of chemical elements was measured on a REM-106I scanning electron microscope. Short-term strength tests (GOST 1497-61, GOST 9651-61, GOST 1497-84) were carried out on standard cylindrical samples (diameter of the working part 5 mm, length 25 mm) at temperatures of 200, 800, 900 and 10000°C on a УМЕ-10TM tensile machine. Long-term strength tests (GOST 10145-81) were performed on standard cylindrical samples at temperatures of 800, 900, 10000°C and corresponding loads of 600, 400, 180 MPa on the AIMA-5-2 machine by uniaxial stretching of samples under constant load. Comparative experimental studies of high-temperature corrosion of alloys were carried out in synthetic ash using a method widely used in the industry. For corrosion tests, standard cylindrical samples (diameter 10 mm, length l = 12 mm) were used, on which, after preliminary degreasing, measurement and weighing on an analytical balance with an accuracy of (± 0.0005 g), synthetic ash in an amount of 12 mg / cm2 was applied to their surface, simulating the combustion products of gas turbine fuel of the following composition, which were placed and kept in a furnace on a platform made of refractory material in an air atmosphere. Obtained results. Studies of the influence of the working environment on the performance of the ГТК-10I hollow blades. It is shown that the working environment significantly affects the performance of the ГТК-10I hollow blades. It was established that the outer layer of the profile part did not show deep damage due to their removal by a high-speed gas flow. It was established that corrosion damage begins from the beginning of operation and the damaged layer contains sulfides of the TiS and Ti2S3 types. It is shown that the short-term strength of the ЗМІ-3 alloy relative to the initial values (passport data) decreases by approximately 16–20 %. It was established that due to structural changes in the alloy during operation, the time to fracture of the samples under load decreased by approximately 18–22 %. Based on the studies performed, the use of protective coatings is necessary to increase performance. Scientific novelty. Obtained results make it possible to evaluate the processes that occur during operation on the surface of products and to establish relationships between alloying elements concentration and the corrosion rate. Practical value. Obtained results allow us to recommend domestic alloys as a substitute for foreign alloys without losing the properties and durability of the products.