SYMPOSIA PAPER Published: 01 January 1969
STP33650S

Effect of Creep-Rupture Ductility and Hold Time on the 1000 F Strain-Fatigue Behavior of a 1Cr-1Mo-0.25V Steel

Source

A single heat of wrought 1Cr-1Mo-0.25V steel was heat treated to a very low and to a higher level of creep-rupture ductility. Completely reversed, uniaxial strain-fatigue tests were run on the two materials at 1000 F with hold times of 1, 10, or 60 min used at the maximum tensile strain point of the cycle. The total strain range in the tests was either 0.5 or 1.0 percent. The cycles to failure decreased significantly as the hold time increased. The hold-time effect was more pronounced in the low than in the high creep-rupture ductility material, and was greater in the 0.5 percent than in the 1.0 percent total strain range tests. Log-log plots of cycles to failure versus hold time formed curves which tended to bend downward, showing an increased hold-time effect at the longer hold times. The fatigue cracks in both the low and the high creep-rupture ductility material tended to shift from transgranular to intergranular as the hold time increased, which indicates that creep-rupture damage occurred during the hold periods.

Author Information

Krempl, E
Rensselaer Polytechnic Institute, Troy, N.Y.
Walker, CD
Structural Metallurgy Unit, Materials and Processes Laboratory, General Electric Co., Schenectady, N.Y.
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Details
Developed by Committee: E08
Pages: 75–99
DOI: 10.1520/STP33650S
ISBN-EB: 978-0-8031-4581-8
ISBN-13: 978-0-8031-0016-9