The MS 5142 gas turbine engine of a GTK 25I gas compressor works as the drive of a centrifugal charger intended for compressing natural gas and transporting it along gas main pipelines. The working compressor blades are one of the key components of the inlet part of the GTE. Exposed to high tempera tures (~300°C), flexural and tensile stress, and increased humidity and dust levels, they therefore operate in very complex conditions. As a result of this kind of operation, the material of the blades undergoes dura bility reducing structural changes that restrict their further operability.Nowadays, traditional ways of increasing the life of machine components, for instance, chemical ther mal processing, often appear to be economically unrewarding for they require the use of expensive and rare elements (chromium, molybdenum, vanadium, titanium, nickel, etc.) and consume considerable energy. Hence, it is reasonable to apply to working surfaces reinforcing and protective coatings with improved resistance and anticorrosion properties. Restorative and repair technologies in which ionic and plasma coatings are used have been developed and successfully applied by specialists from OOO NPTs Tri bonica [1, 2] to extend the life of the components of the flow part of the GTE. The development of non destructive methods for controlling and examining the material of the blades, both after long term use and repairs, is an urgent task on the agenda.
Using Ultrasound for Nondestructive Control of Structural State of Construction MaterialsNowadays, acoustic methods of nondestructive control and diagnostics find an ever increasing appli cation in different industries and at different stages of production, operation, and repair. Basically, the acoustic method of study involves measuring the vital information characteristics, i.e., attenuation and propagation speed of elastic waves in the material, and the analysis of experimental dependencies. The echo pulse approach can be considered the most common type of ultrasonic product control. About 90% of objects controlled using acoustic procedures are examined with the help of the echo method. Using dif ferent types of waves, it is applied in flaw detection of forged pieces, casts, welded joints, many nonmetal lic materials, and also to determine product size. The arrival time of the bottom signal is measured, and, knowing the speed of ultrasound in the material, the product thickness is defined for an article with uni lateral access. If the thickness is already known, then the bottom signal is used to measure ultrasound speed and attenuation [3].The most popular methods of ultrasonic control are based on evaluating ultrasound attenuation in the material, which is determined, first of all, by an increased sensitivity of the given parameter to structural changes in the material. The possibility of analyzing structures of metals with the help of ultrasound was first discovered by S. Ya. Sokolov. Late in the first half of the past century he found that ultrasound dissi pation depends very much ...