Stakyan, M., Pirumyan, N. and Martirosyan, A. 2026. Improving Fatigue Resistance of Gas Transportation System Elements by Using the Hardening Techniques . Scientific Papers of National University of Architecture and Construction of Armenia. 94, 1 (Jun. 2026), 150–161. DOI:https://doi.org/10.54338/18294200-2026.1-15.