SYMPOSIA PAPER Published: 01 January 1985

Computerized Near-Threshold Fatigue Crack Growth Rate Testing at Cryogenic Temperatures: Technique and Results


A computerized near-threshold fatigue crack growth rate (FCGR) test method has been applied at cryogenic temperatures. Near-threshold FCGR tests were conducted at room and cryogenic temperatures as low as 4.2 K (−452°F) on JBK-75 (modified A-286) stainless steel (base and autogenous gas-tungsten arc weld metal). Near-threshold crack growth rates in both the base and weld metal tended to decrease with decreasing temperatures from 297 to 4.2 K (75 to −452°F). At each temperature, the JBK-75 base material typically demonstrated a higher threshold stress intensity range than the weld material. Unlike the room temperature results, at 77 and 4.2 K (−320 and −452°F) near-threshold crack propagation rates were insensitive to load ratio (R = Pmin/Pmax). The decreased dependence of near-threshold FCGR data on load ratio at low temperatures appears to be in agreement with a crack closure model.

Author Information

Liaw, PK
Logsdon, WA
Attaar, MH
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Developed by Committee: E08
Pages: 173–189
DOI: 10.1520/STP32754S
ISBN-EB: 978-0-8031-4924-3
ISBN-13: 978-0-8031-0411-2