Failure Analysis And Improvement Measurement Of 304H Stainless Steam Connecting Pipe

This paper mainly focuses on the case that the steam pipeline gained deformation and developed cracks after half of a year run. The steam pipeline, attached to the steam outlet pipeline of an internal heat exchanger in a dehydrogenation reactor, is made of stainless steel 304H. To the cracks developed in the pipeline, physical and chemical inspection was carried. And to the deformation, cause analysis and finite element simulation were carried. Analytically, the cracks were induced by thermal fatigue, and the deformation was caused by unsteadiness. The unsteadiness happened when the expansion of the pipeline, which was caused by the system thermal expansion, was restricted axially. In case of the recurrence of similar events, some improvement measures are put forward. It is advised that the pipeline should be insulated in the outside, and after the calculation of system thermal expansion, new suited dampers and spring hangers should be installed. The advices were adopted, and after 1.5 years of service, the steam pipeline still works well, so the measurements work is practicable.