Fatigue Stress Corrosion Cracking of Steel X20Cr13 Under Pulsating Tensile Stress in Media Containing Chloride Ions at Temperatures up to 200 degree C.

The 0. 2% C, 13% Cr steel, in the quenched and tempered condition, was tested under conditions simulating the operating conditions of a steam turbine. The media were 15% MgCl//2, 27% NaCl, and 3% NaCl solutions. Compared with tests in air, corrosion fatigue strengths decreased with increase to the boiling points of the solutions. At temperatures above the boiling points, an increase of corrosion fatigue was observed in NaCl, but not in MgCl//2 solutions. The mechanisms of this behavior are explained by the results of microfractography investigations.