To clarify the influence of sodium-chloride (NaCl) content and steam environment on fatigue strength of 13Cr stainless steel, rotating-bending fatigue tests were conducted. Fatigue strength at 10⁷ cycles in 3 percent NaCl aqueous solution was 70 percent lower than that in air. The lower the NaCl content, the longer the fatigue life is in the same stress level. The degree of the influence of steam on fatigue life decreases with decreasing the stress, and no influence was found in the fatigue limit. Corrosion pits and subcracks were found in all tested environments except air.

Corrosion pits were also observed at crack initiation region on fracture surface. Striation was predominant at fatigue life lower than 6 × 10³ cycles in 3 to 3 x 10⁻³ percent NaCl and 2 x 10⁴ cycles in steam environment.

At longer fatigue life, intercrystalline fracture pattern was predominant.