CORROSION FATIGUE FRACTURE-MODE MAPS OF LOW ALLOY STEELS

1992 ◽  
Vol 15 (1) ◽  
pp. 23-32 ◽  
Author(s):  
Zhiqiang Xing ◽  
Yujiu Song2 ◽  
Mingjing Tu3
Keyword(s):  
Fatigue Fracture ◽  
Corrosion Fatigue ◽  
Fracture Mode ◽  
Low Alloy Steels ◽  
Alloy Steels

Corrosion Fatigue Crack Growth in Clad Low-Alloy Steels—Part I: Medium-Sulfur Forging Steel

1997 ◽  
Vol 119 (3) ◽  
pp. 249-254 ◽  
Author(s):  
L. A. James ◽  
T. A. Auten ◽  
T. J. Poskie ◽  
W. H. Cullen
Keyword(s):  
Fatigue Crack ◽  
Corrosion Fatigue ◽  
Compact Tension ◽  
Initial Crack ◽  
Aqueous Environment ◽  
Low Alloy Steels ◽  
Surface Cracks ◽  
Low Oxygen ◽  
Corrosion Fatigue Crack ◽  
Alloy Steels

Corrosion fatigue crack propagation tests were conducted on a medium-sulfur ASTM A508-2 forging steel overlaid with weld-deposited alloy EN82H cladding. The specimens featured semi-elliptical surface cracks penetrating approximately 6.3 mm of cladding into the underlying steel. The initial crack sizes were relatively large with surface lengths of 30.3–38.3 mm, and depths of 13.1–16.8 mm. The experiments were conducted in a quasi-stagnant low-oxygen (O2 < 10ppb) aqueous environment at 243°C, under loading conditions (ΔK, R, and cyclic frequency) conducive to environmentally assisted cracking (EAC) in higher-sulfur steels under quasi-stagnant conditions. Earlier experiments on unclad compact tension specimens of this heat of steel did not exhibit EAC, and the present experiments on semi-elliptical surface cracks penetrating cladding also did not exhibit EAC.

Development of Engineering Codes of Practice for Corrosion Fatigue

1983 ◽  
Vol 105 (3) ◽  
pp. 255-262 ◽  
Author(s):  
P. M. Scott ◽  
B. Tomkins ◽  
A. J. E. Foreman
Keyword(s):  
Fatigue Failure ◽  
Corrosion Fatigue ◽  
Nuclear Reactor ◽  
Pressure Vessels ◽  
Low Alloy Steels ◽  
Aqueous Corrosion ◽  
Codes Of Practice ◽  
Alloy Steels ◽  
Service Inspection ◽  
Reactor Pressure

The recognition that time-dependent effects of aqueous corrosion can have a large influence on fatigue failure in carbon and low alloy steels for nuclear reactor pressure vessels is having an important influence on the continuing process of revision and improvement of design and inspection codes. The contrasting requirements of engineering codes for design purposes or for in-service inspection purposes are discussed. The critical assumptions in each are highlighted and illustrated with examples incorporating recent improvements in the mechanistic understanding of the development of corrosion fatigue failure. The consequences of adopting a crack-tolerant approach in the design phase, as distinct from the evaluation of defects found in service, are also critically examined.

Reactor Water Environmental Fatigue

2003 ◽  
Author(s):  
William J. O’Donnell
Keyword(s):  
Fatigue Life ◽  
Fatigue Damage ◽  
Corrosion Fatigue ◽  
Low Alloy Steels ◽  
Nuclear Plants ◽  
Alloy Steels ◽  
Stress Concentration Factors ◽  
Rapid Transients ◽  
License Renewal ◽  
Fatigue Life Reduction

Existing nuclear plants were designed based on fatigue data obtained entirely in air environments. We now seek to extend the life of these plants, recognizing that many conservatisms were included in the fatigue stress calculations, stress concentration factors and lumped transients. Since we know how these plants were operated, we can quantify the cyclic rates and coolant chemistry. This makes it feasible to use environmental fatigue life evaluation technology which takes credit for the reduced corrosion fatigue damage which occurs during more rapid transients and for reduced dissolved oxygen levels which produce lesser corrosion fatigue damage in carbon and low alloy steels. Accordingly, the use of Fen environmental fatigue life reduction factors which depend on the cyclic rates, coolant chemistry and temperature are quite useful for evaluating the safe fatigue life of aging plants and for license renewal.

Corrosion-Fatigue (Circumferential) Cracking in Cr-Mo Low Alloy Boiler Tube Steels: Part 1—Initiation and Propagation

1992 ◽  
Vol 114 (3) ◽  
pp. 265-269 ◽  
Author(s):  
B. J. Smith ◽  
A. R. Marder
Keyword(s):  
Crack Propagation ◽  
Corrosion Fatigue ◽  
Propagation Mechanism ◽  
Corrosion Mechanism ◽  
Low Alloy Steels ◽  
Thermal Fatigue Crack ◽  
Initiation And Propagation ◽  
Tube Steels ◽  
Alloy Steels ◽  
Crack Propagation Mechanism

The metallurgical mechanism responsible for the initiation and propagation of circumferentially oriented, fireside cracks on waterwall boiler tubes was investigated. The materials studied were Cr-Mo low alloy steels in the as-received and post-service (exhibited cracking) condition. It was determined that cracks were initiated by a corrosion/fatigue interactive mechanism at the fireside tube surface. The corrosion mechanism is sulfidation while the material fatigue degradation occurs due to thermal stress cycles. Crack propagation occurs by an environmentally assisted thermal fatigue crack propagation mechanism.

Corrosion fatigue behavior of low alloy steels under simulated BWR coolant conditions

2010 ◽  
Vol 405 (1) ◽  
pp. 17-27 ◽  
Author(s):  
J.Y. Huang ◽  
M.C. Young ◽  
S.L. Jeng ◽  
J.J. Yeh ◽  
J.S. Huang ◽  
...  
Keyword(s):  
Corrosion Fatigue ◽  
Fatigue Behavior ◽  
Low Alloy Steels ◽  
Alloy Steels
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