In complex piping systems, spatial constraints often give rise to numerous installation challenges: pre‑formed pipes may fail to fit; and even when pipes are awkwardly bent or repositioned to achieve a temporary fit, localized cold‑working corrections are inevitable. Depending on the pipe diameter and site conditions, these cold‑working corrections can range from a few millimeters to several tens of millimeters, with some cases reaching hundreds of millimeters. Experience has shown that the greater the magnitude of such corrections, the higher the residual internal stresses. These installation‑induced stresses, left unresolved within the piping system, undoubtedly pose significant hidden risks.

　　In a certain engine model, a section of the bearing lubrication oil conduit has repeatedly fractured during service, owing to excessively high installation stresses.

　　Because it can be bent freely and exhibits minimal internal stress even when bent within its rated bending radius, it greatly simplifies installation and helps ensure the safe operation of piping systems. This is the primary reason why certain piping systems must use flexible hoses.