Corrosion fatigue crack growth rate

Fig. 55. Corrosion fatigue crack growth rate in sensitized Type 304SS as a function of potential and frequency in 0.01m Na2S04 solution at AK = 20 MPa m. 250 °C. Open symbols denote transgranular mode of cracking, half-symbols denote mixed transgranular/ intergranular mode of cracking, and closed symbols denote intergranular mode of cracking [114]. Reproduced from Corrosion J. 40, 573 0984) by permission of the Editor.

Fig. 7.120 Corrosion-fatigue-crack-growth rate as a function of stress-in-tensity range for a maraging steel in air and 3% NaCl solution.

Fig. 7.122 Corrosion-fatigue-crack-growth rate as a function of stress-in-tensity range for X-65 line pipe steel in air and in 3.5% NaCl solution under cathodic coupling to zinc. Cycled at indicated frequencies and R = 0.2. Coupled potential = -800 10 mV (SHE). (Note Original reference includes data on which these lines are based.) Source Ref 1 69...

Because the corrosion fatigue crack growth rate is proportional to 0a, the maximum cycle-dependent term at a given liK level is given in terms of the growth rates in pure (deleterious) gas and in the inert (reference) environment, along with 9am, as follows ... 

Figure 9.13. Comparison of normalized (corrosion) fatigue crack growth rates for solution-treated (ST) and solution-treated plus averages (STOA) Ti-6A1-4V alloy in water vapor with model predictions for pressure dependence at room temperatnre (i = 0.1, / = 5Hz)[6],...

Figure 9.16. Variation of cycle-dependent component of corrosion fatigue crack growth rate with inverse frequency (or loading period) for an AISI 4340 steel tested in water vapor (at 585 Pa) at room temperature [10].

Figure 5 Corrosion fatigue crack growth rates as a function of stress intensity for carbon steel A533-B (c.f 1.5403, 1.6310) in high purity water at 288°C, 0.017 mHz, R = 0.2. Compilation of crack rates from 20 various laboratories (round robin test) with coordinated conditions [45]...

Figure 5-25. Effect of oxygen dissolved in the water on the corrosion fatigue crack growth rate of a low alloy steel at 290°C.

In this case the corrosion-fatigue crack growth rate will be... 

Stress Intensity Range. Corrosion fatigue crack growth rates geneiidly increase with increasing stress intensity. Figures 32 and 33(a) demonstrate this trend for alloys 2090-T81 and 7079-T651, respectively. 

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