Activation and Repassivation of Stainless Steels in Artificial Brines as a Function of pH

Research output: Contribution to journalArticleResearchpeer-review

Authors

  • Emir Mujanovic
  • Bojan Zajec
  • Tadeja Kosec
  • Andraz Legat
  • Stefan Hönig
  • Gerald Zehethofer

External Organisational units

  • Slovenian National Building and Civil Engineering Institute
  • OMV Exploration and Production GmbH

Abstract

When planning oil wells with stainless steel components, two possible reasons for depassivation have to be considered-chemical depassivation caused by acidizing jobs and mechanical depassivation caused by various tools and hard particles. The study explores conditions causing chemical activation of investigated steels and circumstances under which repassivation occurs after activation. The main focus of the study is to determine, how quickly various steels can repassivate under different conditions and to find pH values where repassivation will occur after depassivation. The investigated steels were ferritic (martensitic or bainitic) in the cases of 13Cr, 13Cr6Ni2Mo, and 17Cr4Ni2Mo, austenitic in the case of 17Cr12Ni2Mo, and duplex (austenitic and ferritic) in the case of 22Cr5Ni3Mo. Potentiodynamic experiments were employed to obtain electrochemical properties of investigated steels, followed by immersion tests to find ultimate conditions, where the steels still retain their passivity. After obtaining this information, scratch tests were performed to study the repassivation kinetics. It was found that repassivation times are similar for nearly all investigated steels independent of their chemical composition and microstructure.

Details

Original languageEnglish
Article number3811
Number of pages11
JournalMaterials
Volume12.2019
Issue number23
DOIs
Publication statusPublished - 20 Nov 2019