Untersuchung der Sauergasbeständigkeit geschweißter Pipeline Stähle

Translated title of the contribution: Study about sour gas resistance of welded line pipe steels

Andreas Prethaler

Research output: ThesisDiploma Thesis

1779 Downloads (Pure)

Abstract

The performance of sulphide stress cracking tests implies the use of extreme toxic sour gas. To avoid such unsafe circumstances, an alternative test without sour gas was built up. The alternative test involves a constant load test with cathodic sample polarisation during the duration of the experiment at 0.05 A/cm2. As a consequence the steel samples were charged electrochemical with hydrogen. The test solution consists of 5 wt% sodium sulphate and traces of arsenic (III) oxide. The pH value of the solution was adjusted to 1.5 with sulphuric acid. The arsenic oxide acts as a poison like sour gas and was used to inhibit the formation of molecular hydrogen and to enhance the absorption of atomic hydrogen. The main aim of this study was to determine the comparability of the NACE standard tensile test TM0177 with the mentioned alternative test. 8 electric arc welded Materials which differ in their chemical composition, strength and manufacture process were tested at different loads. Furthermore samples were tested under the conditions of the alternative test and NACE standard test without load, to clarify if hydrogen induced cracking can be observed. Also permeation measurements were done to get information about hydrogen diffusion behaviour. Results showed no accordance between NACE standard test and the alternative test, because different failure mechanism occurred.
Translated title of the contributionStudy about sour gas resistance of welded line pipe steels
Original languageGerman
QualificationDipl.-Ing.
Supervisors/Advisors
  • Mori, Gregor Karl, Supervisor (internal)
Award date22 Mar 2013
Publication statusPublished - 2013

Bibliographical note

embargoed until 20-11-2017

Keywords

  • line pipe
  • Sour Service
  • hydrogen charging
  • permation
  • hydrogen induced cracking
  • constant load test

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