<p>The appearance of foreign-made high-pressure cylinders for technical gases on the Ukrainian market requires appropriate experimental testing of their quality to justify their purchase. Experimental studies of the strength parameters of a test batch of high-pressure cylinders (seven sizes, five cylinders of each type), manufactured from seamless tubes, established that two cylinder sizes failed to withstand standard cyclic pressure tests. The probable cause of failure is a manufacturing defect resulting from non-compliance with the regulatory document regarding the radius of curvature of the concave bottom and significant deformations under cyclic test pressure loading. Significant cyclic deformations of the cylinder bottoms contributed to the initiation and propagation of fatigue cracks in the stress concentration zone in the circumferential direction, which led to failure due to the action of longitudinal stresses. The following mechanisms of cylinder failure during standard testing have been experimentally established. Under static loading with increasing internal pressure, failure occurs due to the action of hoop stresses in the longitudinal direction of the cylinders via a quasi-static mechanism with signs of accumulated strain limitation. Under cyclic loading with test pressure, failure occurs due to longitudinal stresses via a low-cycle fatigue mechanism resulting from the initiation and growth of fatigue cracks to critical sizes in the stress concentration zone.</p>