The effect of aqueous medium on fatigue crack growth conditions in materials of power generating facilities

The effect on the fatigue crack growth rate of a corrosion medium, viz. water at 20 degC saturated with air oxygen, was examined for the 15Kh2NMFA steel. Under the given stress conditions, the aqueous medium has a favorable effect in the threshold stress region and in the region of slow crack growth. The threshold stress in water was approximately twice as high as in air. The corrosion product deposit was thickest on the fracture surfaces of the specimens in water. At stress frequencies of 40 to 50 Hz, the aqueous medium saturated with oxygen had no adverse effect. The threshold values in water were appreciably higher than in air whereas in the stable crack growth region, virtually no effect of water was observed. (M.D.). 2 figs., 1 tab., 7 refs