National Polytechnic University of Armenia, Yerevan, Republic of Armenia

O. S. Chibukhchyan, Cand. Eng., Head of Innovation Service, Acting Head of the Dept. of Mechanical Engineering and Automation Technology, e-mail: hovhannesch@gmail.com
G. S. Chibukhchyan, Cand. Eng., Associate Prof., Dept. of Transport Vehicles, e-mail: grigor.chibukhchyan@gmail.com

The drainage (sewage) systems in Yerevan were built more than 50 years ago and do not meet modern environmental standards. Outdated infrastructure often leads to blockages, leaks and accidents, which can cause significant economic losses, as well as damage to both the environment and public health. Practice shows that sewerage pipes often become critical objects that predetermine the sanitary condition and the risk of biological pollution of the environment, increasing the risk of various infectious diseases. Reliability and environmental safety of water supply and sewerage pipelines are one of the main requirements for the water supply and sewerage systems of cities and towns. The practice of operating urban water supply and sewerage systems (sewage) shows that frequent disruptions to normal operation are mainly associated with damage to sections of urban water supply and sewerage networks, which are the most functionally significant and vulnerable elements. This requires the use of new effective technologies to improve the mechanical properties of the inner walls of pipelines without harming the environment. The results of experiments on ultrasonic double-sided hardening for thin-walled plates made of Kh18N9T and 8011 materials measuring 200×400 mm are presented. The surface layer processing depth was 194 μm for Kh18N9T steel and 168.5 μm for 8011 material. In practice, it is advisable to use thin-walled plates made of Kh18N9T material with double-sided ultrasonic hardening (with a hardened layer depth of up to 194 μm) to increase the strength and corrosion resistance of the inner walls of metal pipelines. This will significantly reduce the cost of repair and restoration work on the water supply and sewerage system.
The study was carried out with the financial support of the Committee on Higher Education and Science of the Republic of Armenia (Scientific project No. 22YR-2D040).

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