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Title: Response of bainitic 2 1/4 Cr-1 Mo steel to creep-fatigue loadings at 482/sup 0/C

Technical Report ·
DOI:https://doi.org/10.2172/6734702· OSTI ID:6734702

Creep-rupture, fatigue, and creep-fatigue tests were performed on 150-mm plate of bainitic 2 1/4 Cr-1 Mo steel at 482/sup 0/C. Purpose was to produce exploratory data to assess the sensitivity of the material to time-dependent damage processes. Two material conditions were examined - quenched and tempered (QT) for 6 h at 662/sup 0/C and simulated postweld heat treated (PWHT) for 28 h at 690/sup 0/C. Continuous-cycling fatigue data for the PWHT material revealed better fatigue resistance than reported in the literature. Under creep-fatigue conditions, with relaxation hold times in the range 0.01 to 0.5 h, the fatigue strength was substantially reduced. The PWHT material exhibited slightly poorer fatigue properties under tensile relaxation holds than under compression holds at the 1% strain range level. This behavior pattern is the opposite of the trend reported for annealed 2 1/4 Cr-1 Mo steel and suggests that the mechanism of damage accumulation in this class of material may depend on strain range and microstructure as well as environmental conditions. However, the failure mode for bainitic material was similar to that reported for ferritic (annealed) material. 10 figures, 4 tables.

Research Organization:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
DOE Contract Number:
W-7405-ENG-26
OSTI ID:
6734702
Report Number(s):
ORNL/TM-8392; ON: DE83003195
Country of Publication:
United States
Language:
English