Long-term corrosion of Cr-Mo steels in superheated steam at 482 and 538/sup 0/C. [21/4 Cr-1 Mo; 9 Cr-1 Mo; Sumitomo 9 Cr-2 Mo; Sandvik HT-9]

Conference · Tue Jan 01 00:00:00 EST 1980

OSTI ID:6609462

Griess, J C; DeVan, J H; Maxwell, W A

The corrosion of several Cr-Mo ferritic steels was investigated in superheated steam at an operating power plant. Tests were conducted at 482 and 538/sup 0/C (900 and 1000/sup 0/F) in a once-through loop for times up to 28,000 h. Chromium concentrations ranged from 2.0 to 11.3%, and the effect of surface preparation on corrosion was investigated. Only one of many specimens showed evidence of exfoliation at 482/sup 0/C, but at 538/sup 0/C exfoliation occurred on at least some of the specimens of most materials; the exceptions were the alloy with the highest chromium content (Sandvik HT-9), one heat of 9 Cr-1 Mo steel with the highest silicon content, and Sumitomo 9 Cr-2 Mo steel, which was in test for only 19,000 h. Parabolic oxidation kinetics adequately described the corrosion process for about the first year, after which corrosion rates were constant and lower than predicted from extrapolation of the initial part of the penetration versus time curves. With chromium concentrations between 2 and 9%, corrosion behavior was independent of chromium content, and corrosion was only slightly less with Sandvik HT-9. Corrosion was nearly independent of surface preparation, but in two cases the presence of mill scale on the surface prior to steam exposure seemed to retard oxidation in steam. 11 figures, 5 tables.

• Research Organization: Oak Ridge National Lab., TN (USA); NUS Corp., Clearwater, FL (USA)
• DOE Contract Number: W-7405-ENG-26
• OSTI ID: 6609462
• Report Number(s): CONF-810402-8
• Resource Relation: Conference: Corrosion/81 annual meeting, Toronto, Canada, 6 Apr 1981
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
ALLOY-HT-9
CORROSION
CHROMIUM-MOLYBDENUM STEELS
STEAM
CORROSIVE EFFECTS
EXPERIMENTAL DATA
GRAPHS
HIGH TEMPERATURE
SUPERHEATING
TABLES
ALLOYS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CHROMIUM STEELS
DATA
HEATING
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
NUMERICAL DATA
STEELS
360105* - Metals & Alloys- Corrosion & Erosion