Creation of Industrial Equipment for High Frequency Mechanical Impact on Railway Car Building Products and Methods for Assessing the Quality of Treatment

1Prokopenko, GI
1Mordyuk, BM
2Krasovsky, TA
3Knish, VV
3Solovey, SO
1Kurdyumov Institute for Metal Physics of the NAS of Ukraine
2Kyiv Academic University of the NAS and MES of Ukraine
3Paton Institute of Electric Welding of the NAS of Ukraine
Sci. innov. 2019, 15(2):25-37
Section: Research and Engineering Innovative Projects of the National Academy of Sciences of Ukraine
Language: English
Introduction. The technology of high-frequency mechanical impact (HFMI) has proved itself to be a reliable, efficient, and convenient method for increasing the fatigue strength of welded structures, which is one of the most priority tasks of the machine-building industry.
Problem Statement. The experience of operating the HFMI equipment and technology has shown that there are many problems associated with the determination of the process quality and completeness. The creation of ultrasonic equipment for HFMI with electromechanical piezo-ceramic transducers was initiated at the Kurdyumov Institute for Metal Physics of the NAS of Ukraine. Over the years, this equipment has been used both for scholarly research and for processing of various products and structures. However, neither the HFMI equipment and nor HFMI technology has been commercialized so far.
Purpose. To create a new ultrasound equipment having a high reliability and a significant operation resource suitable for the use in the operating conditions and to develop tools for evaluating the HFMI process quality regarding welded joints of certain parts and railway-car building products.
Materials and Methods. Low-alloy structural steels St3сp and 09G2S. Hardness / microhardness measurements and optical microscopy.
Results. A mock-up of ultrasonic equipment has been made. It has has passed comprehensive industrial tests at Kriukov Railway Car Building Works, Public Joint-Stock Company (“KRCBW” PJSC), Kremenchuk, Ukraine. Some deficiencies of the equipment identified during the tests have been eliminated in a new model of the equipment. A method for determining the HFMI process productivity and the duration of treatment of welded joints has been suggested. It is based on simple microhardness measurements. The quality and completeness of the treatment has been additionally checked by visual inspection of a groove formed by impact elements.
Conclusions. A new ultrasound equipment has been manufactured, and technological recommendations on choosing treatment regimes for railway carriage trolleys and other products of KRCBW PJSC have been proposed.
Keywords: high-frequency mechanical impact, metal fatigue, microhardness, quality and duration of treatment, ultrasonic equipment, welded joints