SEDL / STP / STP536-EB / STP49642S

Fatigue Crack Propagation and Fracture Toughness of 5Ni and 9Ni Steels at Cryogenic Temperatures

Bucci, R. J.
Vice president of Research, Del Research Corp., Hellertown, Pa.

Greene, B. N.
Project metallurgist, Esso Research and Engineering Company, Florham Park, N. J.

Paris, P. C.
President, Del Research Corp., Hellertown, Pa.

Pages: 23    Published: Jan 1973

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Abstract

Fracture mechanics techniques were used to investigate low temperature fatigue crack propagation properties of 5Ni and 9Ni steels. The 5Ni alloy was also tested in the welded condition. Fatigue loading was primarily zero tension, but some data were taken for fully reversed, compression-tension loading in the unwelded materials. Conventional log-log plots of range in stress intensity parameter, ΔK, versus cyclic growth rate, Δa/ΔN, were used to assess material fatigue crack propagation behavior at −320°F, −260°F, and room temperature (70°F). Fracture toughness measurements were also obtained at −260 and −320°F for both steels and for the heat affected zone (HAZ) of the welded 5Ni steel.