THE BEHAVIOR OF FATIGUE CRACK-GROWTH IN THE FRETTING-CORROSION-FATIGUE OF HIGH-TENSILE ROPING STEEL IN AIR AND SEAWATER

Abstract— Fretting fatigue tests of high tensile roping steel, 1.5 mm in diameter, 1770 MPa grade, were carried out in air and seawater. S‐N curves were completed in both the environments and under cathodic protection at‐850 mV (SCE). The crack growth curves were determined at three different alternating stress levels. The coefficients of friction between the specimen and the fretting bridge, where the macro‐slip occurred, were found to be 0.63 in air and 0.38 in seawater. The prediction of the fretting fatigue lives were made according to the Tanaka—Mutoh model, where the frictional force was taken into consideration. The predicted fatigue life agreed well with the experimental results in air but in seawater the prediction defined a much higher fatigue limit compared with the experimental results which showed the absence of the fatigue limit. These results indicate that the method of removing the electrochemical component is very promising for the prevention of fretting fatigue failure in seawater. Copyright © 1991, Wiley Blackwell. All rights reserved