Effect of low-temperature aging on the mechanical properties of cast stainless steels

Conference · Wed Jul 01 00:00:00 EDT 1987

OSTI ID:5849736

Chopra, O K; Chung, H M

The significance of in-service embrittlement of cast duplex stainless steels under light-water operating conditions was investigated. Mechanical property data are presented from Charpy-impact, tensile, and J-R curve tests for several heats of cast stainless steel aged up to 10,000 h at 450, 400, 350, 320, and 290/sup 0/C. Thermal aging increased the tensile strength and decreased the impact energy, J/sub IC/, and tearing modulus of the steels. Also, the ductile-to-brittle transition curve shifted to higher temperatures. Fracture toughness results were consistent with the Charpy-impact data. The ferrite content and concentration of C in the steel had a strong effect on the overall process of low-temperature embrittlement. The low-carbon CF-3 steels were the most resistant and Mo-containing CF-8M steels were most susceptible to embrittlement. Weakening of the ferrite/austenite phase boundaries by carbide precipitates had a significant effect on the kinetics and extent of embrittlement of the high-carbon CF-8 and CF-8M steels, particularly after aging at temperatures greater than or equal to400/sup 0/C. The influence of N content and distribution of ferrite on loss of toughness are discussed. Data also indicate that existing correlations do not accurately represent the embrittlement behavior over the temperature range 280 to 450/sup 0/C. 16 refs., 22 figs., 2 tabs.

• Research Organization: Argonne National Lab., IL (USA)
• DOE Contract Number: W-31109-ENG-38
• OSTI ID: 5849736
• Report Number(s): CONF-871232-2; ON: DE88002872
• Resource Relation: Conference: Symposium on properties of stainless steels in elevated temperature service, Boston, MA, USA, 13 Dec 1987; Other Information: Portions of this document are illegible in microfiche products
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
22 GENERAL STUDIES OF NUCLEAR REACTORS
STAINLESS STEELS
AGING
CORROSION RESISTANCE
EMBRITTLEMENT
HEAT TREATMENTS
WATER COOLED REACTORS
MATERIALS TESTING
ACTIVATION ENERGY
CARBIDES
CARBON ADDITIONS
CHARPY TEST
COMPARATIVE EVALUATIONS
DUCTILE-BRITTLE TRANSITIONS
FERRITIC STEELS
HIGH TEMPERATURE
IMPACT STRENGTH
MECHANICAL PROPERTIES
MICROSTRUCTURE
MOLYBDENUM ALLOYS
NITROGEN
PRECIPITATION HARDENING
STRESS CORROSION
ALLOYS
CARBON COMPOUNDS
CHEMICAL REACTIONS
CHROMIUM ALLOYS
CORROSION
CORROSION RESISTANT ALLOYS
CRYSTAL STRUCTURE
DESTRUCTIVE TESTING
ELEMENTS
ENERGY
HARDENING
IMPACT TESTS
IRON ALLOYS
IRON BASE ALLOYS
MECHANICAL TESTS
NONMETALS
REACTORS
STEELS
TESTING
360103* - Metals & Alloys- Mechanical Properties
360102 - Metals & Alloys- Structure & Phase Studies
220200 - Nuclear Reactor Technology- Components & Accessories