Development of High Interstitial Stainless Steel and Evaluation of Its NaCl Corrosion Resistance

Cheolmin Ahn, Hyunju Lee, Yoonseok Lee, Seungchan Cho, Brajendra Mishra, Eunkyung Lee

Research output: Contribution to journalArticle

Abstract

Abstract: High interstitial Fe–Cr–Mn–C–N stainless steels, CN66 (0.38 wt% N + 0.28 wt% C) and CN71 (0.44 wt% N + 0.27 wt% C), were cast under atmospheric pressure to develop a new drill collar for use in petroleum industry. To evaluate the corrosion property, CN66 and CN71 were compared with high-Mn stainless steel, P550, which is currently being used as a drill collar material. Through the measurement of the corrosion resistance based on the chemical compositions, CN71 exhibited the highest corrosion property, a mean of 35.74, corresponding to strong corrosion resistance. However, CN71 exhibited a mean of 0.517 mpy for the corrosion rate compared to 0.37 mpy for P550, after the immersion experiment in 3.5 wt% NaCl. With high C content, the formation of carbide along the grain boundaries in CN71 and CN66 caused intergranular corrosion. However, this could be restricted by heat treatment at 1050 °C and 1180 °C with uniform distributions of chemical compositions via air cooling, decreasing the corrosion rates significantly. Graphic Abstract: [Figure not available: see fulltext.].

Original languageEnglish
JournalMetals and Materials International
DOIs
Publication statusAccepted/In press - Jan 1 2019

Keywords

  • Corrosion resistance
  • Heat treatment
  • High interstitial stainless steel
  • Microstructure

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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