Use of the Instrumented Bolt and Constant Displacement Bold-Loaded Specimen to Measure In-Situ Hydrogen Crack Growth in High-Strength Steels

Abstract

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Mathematical models for flaw and damage tolerance analyses

“…This estimate of d is much larger than the estimate given in [3] and [6]. Note: The ASTM grain size number 1 of conventionally heat treated AF1410 steel is approximately 10.8 [7]. This corresponds to an average grain size of approximately 8.5 µm.…”

Experiences and Modeling of Hydrogen Cracking in a Thick-Walled Pressure Vessel

“…Scenario #2 -No localized hardened layer in concentrated H 2 S0 4 Had we simply replaced the 50% H 2 SCV50% H3PO4 with concentrated H 2 S0 4 , and not had a 4-mm deep hardened layer, it is likely that the cracking would have occurred within the duration of the 1500-hour test. An expected incubation time would be 312 hours followed by crack advancement, nearly through the wall in the next 32 hours of exposure.…”

Failure Beneath Cannon Thermal Barrier Coatings by Hydrogen Cracking; Mechanisms and Modeling

“…Vigilante et al (refs 1,2) have tested a variety of high-strength steel and nickel-iron base alloys in electrolytic cell and acid hydrogen environments using automated crack-growth methods with a bolt-load compact specimen incorporating an instrumented-bolt. Their most striking finding in relation to the alloy steels used for cannons was their extreme sensitivity to hydrogen cracking at yield strengths of 1100 MPa and above.…”

“…The residual stress is of opposite sense to the applied stress and of a value equal to the difference between the applied stress and the yield strength, as shown by equation (2). It is important to account for the change in the steel yield strength with temperature when calculating residual stress using equation (2). If the room temperature value of strength were used, an underestimate of the tensile residual stress and its depth would result.…”