Fatigue Failure of Hydrocarbon Piping System

摘要

AbstractThis paper presents a case study of hydrocarbon piping made of ASTM A376 TP321 stainless steel. The feedstock was of a two-phase flow hydrocarbon with small amount of sulfur. The pipe was found to be leaked at the weldment after 8?years of service. A combination of techniques including visual inspection, emission spectroscopy, radioscopy, scanning electron microscopy, and optical microscopy was applied to identify the possible cause of failure. The results showed that the cracks originated at the external wall of the pipe and were a consequence of synergy of fatigue loading during service due to improper piping support and stress concentrations as a result of the welding process. Deformation twinning and strain hardening may also contribute to the failure. According to failure and stress analysis done in this work, it is recommended that careful control of cyclic loading must be improved by, for example, implementation of a better spring constant for piping support system. In addition, a process for stress raiser-free welded structure should be of concern to achieve complete failure prevention in the future.