Effects of Overloads on the Incubation Time for Stress Corrosion Cracking of 7075 Aluminum

CORROSION ◽  
1982 ◽  
Vol 38 (6) ◽  
pp. 330-335 ◽  
Author(s):  
A. H. Hanisch ◽  
L. H. Burck
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
Incubation Time ◽  
High Strength ◽  
Critical Stress Intensity Factor ◽  
Corrosion Cracking ◽  
Cracking Behavior

Abstract A series of tests was conducted on precracked high strength aluminum alloy 7075-T651 plate to determine the effects of overstressing on the short-transverse stress corrosion cracking behavior. Fatigue precracked wedge-opening-loading specimens were preloaded in air to various percentages of the critical stress intensity factor, unloaded, and reloaded statically to lower stress intensity factor levels. The samples were then alternately immersed in an aqueous 3.5% sodium chlorine solution for stress corrosion testing. The incubation time which preceded crack extension by stress corrosion cracking was found to increase substantially for higher percentages of preloading. Furthermore, for a given percentage of prestress overload, greater effects were observed for higher applied stress intensity factor levels. The increase in incubation period produced by stress overloading is attributed primarily to the effects of residual compressive stresses at the crack tips.

Fracture Toughness Assessment of the Susceptibility for Sulfide Stress Corrosion Cracking in High Strength Carbon Steels: A review

CORROSION ◽  
10.5006/3610 ◽  
2020 ◽  
Author(s):  
Raymundo Case ◽  
Bostjan Bezensek
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Stress Corrosion ◽  
Stress Corrosion Cracking ◽  
High Strength ◽  
Carbon Steels ◽  
Sulfide Stress ◽  
Sulfide Stress Corrosion Cracking

High strength carbon steels typically used as oil country tubular goods can be susceptible to sulfide stress corrosion cracking (SSC) when in service in environments that contain H2S. In the last 25 years, linear-elastic fracture mechanics has been used to understand both the mechanistic aspects of this form of cracking and to quantify the susceptibility to SSC of different OCTG steel grades. This paper presents a review on the evolution of the Double Cantilever Method (DCB) as a standard practice to assess the threshold stress intensity factor KISSC. The paper evaluates the capabilities and limitations of this testing method to describe the conditions associated with crack propagation. The review study indicates that new fracture parameters based on the energy required for crack propagation such as J-integral JIc might be required to overcome the limitations of the static conditions implied in the stress intensity factor KIc evaluation approach

Closed-Form Stress Intensity Factor Solutions for Deep Surface Cracks in Plates

2017 ◽  
Author(s):  
Kisaburo Azuma ◽  
Yinsheng Li ◽  
Kunio Hasegawa ◽  
Steven Xu
Keyword(s):  
Stress Intensity Factor ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Stress Corrosion ◽  
Closed Form ◽  
Stress Corrosion Cracking ◽  
Corrosion Cracking ◽  
Influence Coefficient ◽  
Surface Cracks ◽  
Deep Surface

Materials made of Alloy 82/182/600 used in light-water reactors are known to be susceptible to stress corrosion cracking. It is known that the depth a of some cracks due to primary water stress corrosion cracking is larger than the half-length c. The stress intensity factor solution for cracks plays an important role to predict crack propagation and failure. However, Section XI of the ASME Boiler and Pressure Vessel Code does not provide the solutions for cracks with large aspect ratios a/c. In this study, closed-form stress intensity factor influence coefficients for deep surface cracks in plates are discussed. The crack tip stress distribution is represented by a fourth degree polynomial equation. Influence coefficient tables obtained by using finite element analysis in previous studies are used for curve fitting. The closed-form solutions for the coefficient were developed at the surface points and the deepest points of the cracks with aspect ratio a/c ranged from 1.0 to 8.0. The solutions for the points where the stress intensity factor reaches maximum were also investigated.

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