Use of material characterization to complement fracture mechanics in the analysis of two pressure vessels for further service in a hydrogenating high-temperature process

Klaus Rahka

Research output: Chapter in Book/Report/Conference proceedingConference article in proceedingsScientificpeer-review

1 Citation (Scopus)

Abstract

Cracks of significant size were found in two chemical process pressure vessels after around 100 000-h service. The finding warranted fracture mechanics evaluation of further service fitness. This was done in five steps: fracture toughness measurements including determination of aging effects, loading limit identification including estimation of further aging and hydrogen effects, stress-intensity factor calculations, material and cracking mechanism investigation, and recommendations of precautions. The principal reason for crack formation was found to have been hydrogen attack due to local insufficient alloying in repair welds. Sufficient safety margins for further service were provided by a combination of precautions during startup and shutdown operations, low-working stresses, and sufficient fracture toughness as well as a detailed service record. Recommendations for further precautions included more frequent and intensified recurrent inspection, inert gas pressurization, and limitation of process pressures at ambient and lower temperatures during startups and shutdowns.
Original languageEnglish
Title of host publicationCase Histories Involving Fatigue and Fracture Mechanics
EditorsC.M. Hudson, T.P. Rich
Place of PublicationPhiladelphia
PublisherAmerican Society for Testing and Materials (ASTM)
Pages3-30
ISBN (Electronic)978-0-8031-4983-0
ISBN (Print)978-0-8031-0485-3
DOIs
Publication statusPublished - 1986
MoE publication typeA4 Article in a conference publication
EventASTM Symposium on Fracture Testing - Charleston, United States
Duration: 21 Mar 198522 Mar 1985

Publication series

SeriesASTM Special Technical Publication
Volume918
ISSN0066-0558

Seminar

SeminarASTM Symposium on Fracture Testing
Country/TerritoryUnited States
CityCharleston
Period21/03/8522/03/85

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