Thermal stability of ferritic alloys for fossil-fuel processing systems. Final technical report, September 1, 1978-August 31, 1981. [at 475/sup 0/C]

Technical Report · Thu Dec 31 00:00:00 EST 1981

DOI:https://doi.org/10.2172/5228937· OSTI ID:5228937

Polonis, D. H.; Spear, W. S.

This research program has investigated the thermal stability of several ferritic stainless steels containing 15 to 18 weight percent chromium over the temperature range 400/sup 0/C to 550/sup 0/C where the 475/sup 0/C embrittlement reaction is of concern. A major part of the experimental work was concerned with the effect of ternary additions of up to 6 weight percent; aluminum on the kinetics and the magnitude of the embrittlement reaction. The work also included a binary Fe-18Cr alloy, a ternary Fe-18Cr-2Mo, and two commercial alloys, Armco type 430 and type 18SR. Resistometric studies of the kinetics of microstructural instability indicated that aluminum additions promote the tendency of chromium atoms to cluster at temperatures in the vicinity of 475/sup 0/C. The magnitude of embrittling reaction is intensified by the aluminum additions which are expected to restrict dislocation cross slip and increase the coherency strains associated with the alpha prime precipitates. Activation energy determinations for the decomposition reaction indicate that the rate controlling process is most likely determined by the diffusion of chromium, and the tendency of aluminum to enhance the clustering of chromium atoms is similar to the effect reported for molybdenum additions by previous workers.

• Research Organization: Washington Univ., Seattle (USA). Dept. of Mining and Metallurgical and Ceramic Engineering
• DOE Contract Number: FG01-78ET13711
• OSTI ID: 5228937
• Report Number(s): DOE/ET/13711-T2; ON: DE82013575
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
STAINLESS STEELS
EMBRITTLEMENT
STABILITY
ALUMINIUM
CHROMIUM STEELS
CORROSION RESISTANCE
EXPERIMENTAL DATA
PHASE TRANSFORMATIONS
SULFIDATION
ALLOYS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CORROSION RESISTANT ALLOYS
DATA
ELEMENTS
INFORMATION
IRON ALLOYS
IRON BASE ALLOYS
METALS
NUMERICAL DATA
STEELS
360102* - Metals & Alloys- Structure & Phase Studies
360105 - Metals & Alloys- Corrosion & Erosion