The detailed examination of two stainless steel specimens oxidised for 20,000 hours in high pressure CO2/2% CO

✍ Scribed by A. F. Smith

• Publisher: John Wiley and Sons
• Year: 1982
• Tongue: German
• Weight: 851 KB
• Volume: 33
• Category: Article
• ISSN: 0947-5117
• DOI: 10.1002/maco.19820330202

✦ Synopsis

Abstract

Detailed examination has been carried out on two specimens of 18/8 steels representing the extremes of the rates of parabolic duplex scale growth at 600°C using metallography, scanning electron microscopy, microprobe and nuclear microprobe analysis.

The high growth rate material, vacuum annealed 316, had an inner layer of mainly a uniform spinel but with a chromium rich low nickel spinel (healed oxide) at the metal interface. The underlying alloy was extensively carburised with a carbon concentration near the metal surface of ∼1 wt%. The low growth rate material had a more complex inner layer and a much lower degree of carburisation. The results are explained in terms of the composition of the inner oxide and the rate of healing layer formation being controlled by the prevailing oxygen potential there.