Corrosion-Fatigue Crack Propagation Studies of Some New High-Strength Structural Steels

1969 ◽  
Vol 91 (4) ◽  
pp. 570-574 ◽  
Author(s):  
T. W. Crooker ◽  
E. A. Lange
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Salt Water ◽  
High Strength ◽  
Structural Steels ◽  
Stress Intensity Factor Range ◽  
Corrosion Fatigue Crack ◽  
Crack Growth Rates

Fatigue crack propagation studies were conducted on three new high-strength structural steels: 9Ni–4Co–0.20C quenched-and-tempered, 10Ni–2Cr–1Mo–8Co dual-strengthened, and 13Cr–8Ni–2Mo precipitation-hardened stainless. The yield strengths of these steels ranged from 176 to 193 ksi. Notched cantilever-bend specimens of each steel were cycled zero-to-tension in two environments, room air and 3.5 percent NaCl salt water. Fatigue crack growth rates were measured experimentally and correlated with the crack tip stress-intensity factor range. The results indicate that these new steels possess greater resistance to fatigue crack propagation and less sensitivity to environment than previously studied steels of comparable strength.

Experimental Investigations of Fatigue Crack Propagation for Pipe Under Torsional Loading

2010 ◽  
Author(s):  
Motoki Nakane ◽  
Satoshi Kanno ◽  
Shota Hashimoto ◽  
Takayuki Watanabe ◽  
Yukio Takahashi
Keyword(s):  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Intensity Factor ◽  
Crack Propagation ◽  
Crack Growth ◽  
Fatigue Crack Propagation ◽  
Growth Rates ◽  
Torsional Loading ◽  
Crack Growth Rates

This study discusses methods for evaluating fatigue crack propagation under torsional loading for pipes. To achieve this objective, fatigue crack propagation tests were carried out on both stainless steel and carbon steel used in piping systems of nuclear power plants. Two different kinds of pipes were tested in this study. These pipes had the same shape but the diameter and thickness of the larger pipe were twice those of the smaller pipe. The nominal shear stress amplitudes applied to the specimen were set between 50 and 100 MPa depending on the dimension of the specimen and desired crack growth rates. All fatigue tests were conducted under pure torsional loading with stress ratio R = −1 and at room temperature. The geometrical correction factors for the specimen were derived from elastic J-integral calculated by the FEM. The fatigue crack propagation tests results show that the crack growth rates estimated by the elastic stress intensity factor with the geometrical correction factor were much faster than curves prescribed in The Japan Society of Mechanical Engineers (JSME) codes. These results suggest that elastic plastic fracture parameters should be considered into the stress intensity factor because yield stresses for torsional loading would be smaller than those of uniaxial loading. The plastic zone correction method and modified reference stress method were examined as alternative methods. The crack growth rates estimated by the proposed methods almost totally correspond to the JSME curves. The two proposed methods were found to be quite effective at correctly evaluating the crack growth rates under torsional loading.

Fatigue and Corrosion-Fatigue Crack Propagation in Intermediate-Strength Aluminum Alloys

1973 ◽  
Vol 95 (3) ◽  
pp. 150-156 ◽  
Author(s):  
T. W. Crooker
Keyword(s):  
Growth Rate ◽  
Fatigue Crack ◽  
Stress Intensity ◽  
Aluminum Alloys ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
High Stress ◽  
Stress Intensity Factor Range ◽  
Stress Intensity Range ◽  
Corrosion Fatigue Crack

Fatigue crack propagation studies were conducted on a variety of intermediate-strength aluminum alloys under high stress-intensity range cycling (ΔK > 10 ksiin.). Tests were conducted in ambient room air and in 3.5-percent NaCl saltwater environments. Data are presented on log-log coordinates in terms of fatigue crack growth rate (da/dN) as a function of the stress-intensity factor range (ΔK). Comparisons are made among similar crack propagation data for steel and titanium alloys.

Effects of Negative Stress Ratios on Crack Propagation Behavior After an Overload

2003 ◽  
Vol 17 (08n09) ◽  
pp. 1580-1586 ◽  
Author(s):  
C. Makabe ◽  
A. J. McEvily ◽  
A. Purnowidodo ◽  
A. Yamauchi
Keyword(s):  
Growth Rate ◽  
Stress Intensity Factor ◽  
Fatigue Crack ◽  
Crack Propagation ◽  
Fatigue Crack Propagation ◽  
Stress Intensity Factor Range ◽  
Fatigue Crack Propagation Behavior ◽  
Propagation Behavior ◽  
Stress Ratios ◽  
Crack Propagation Behavior

A study of the effect of an overload on fatigue crack propagation behavior has been carried out at baseline R-values of 0, -1, and -1.5. The usual delayed retardation event was observed at R = 0. At R = -1 the degree of retardation was reduced. At R = -1.5 the fatigue crack growth rate was observed to accelerate after the overload. These behaviors were related to the extent of crack closure, which existed following the overload. The rate of fatigue crack propagation for all loading conditions was correlated with the parameter Δ K eff - Δ K effth , where Δ K effth is the effective value of the stress intensity factor range at threshold.

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