IMPROVEMENT IN DURABILITY OF WELDED DRUMS COMPRESSOR ROTORS BY TREATMENT IN FLUDIZED BED OF ABRASIVE MATERIAL

Abstract

Purpose. Improvement in durability of welded drums of compressor rotors of the gas turbine engines by treatment in fluidized bed of abrasive material. Methods of research. The investigations were carried out on the welded drums of rotors of high pressure compressor (HPC) of the D-36 aero engine. The drums were treated in the fluidized bed of abrasive material of the АПС-600 installation without the nozzles and with the use of special air-blast nozzles. Test specimens for checking durability were cut of HPC stages 1 and 4 discs after carrying out various machining processes. Durability testing of test specimens cut of HPC stage 4 disc was carried out at the УМЭ-1 ТМ machine at temperature  Т = 400 °С. Durability testing of test specimens cut of HPC stage 1 disc was carried out at the ЭДЦ-20 machine at temperature Т = 20 °С. Results. It was found that averaged cyclic life of the test specimens made of titanium alloy ВТ-9, treated in the fluidized bed of abrasive material being a part of the drum with the use of air-blast nozzles, is 2.2 times higher than the averaged cyclic life of the test specimens treated in the fluidized bed of abrasive material without the use of air-blast nozzles at temperature Т = 400 °С. When treating the drum of the HPC rotor in the fluidized bed of abrasive material without the use of air-blast nozzle, better treatment of the bottom of the slot and corners of its end faces is ensured. Low-temperature annealing of the drum at temperature Т = 550 °С is preferable than at Т = 750 °С, since cyclic life of the test specimens annealed at Т = 550 °С is somewhat higher. Annealing at Т = 750 °С removes completely strengthening effect obtained by treatment in the fluidized bed of abrasive material. Successive treatment of the disc as a part of the drum in the fluidized bed restores its durability to the initial state. Scientific novelty. It was demonstrated that treatment of the welded drums of the compressor rotors in the fluidized bed of abrasive material with the use of special air-blast nozzles improves the quality of treatment and cyclic life if compared to the treatment without air-blast nozzles. Annealing temperature for the compressor rotor drum, which ensures high average cyclic life, was established. Practical value. There were offered technological procedure and modes of treatment of the welded drums of the HPC of the D-36 aero engine in the fluidized bed of abrasive material with the use of special air-blast nozzles, ensuring durability 2.2 times higher than without the use of the air-blast nozzles.