AN ANALYSIS OF THE EFFECTS OF SULFUR-CONTENT AND POTENTIAL ON CORROSION-FATIGUE CRACK-GROWTH IN-REACTOR PRESSURE-VESSEL STEELS

The present work characterizes the effects of sulphur content and appl ied potential on the corrosion fatigue crack propagation rate in nucle ar reactor pressure vessel steels. The data for the characterization w ere achieved by conducting the tests on A533B type steels, subjected t o a sine-waveform loading at 0.0167 Hz in stagnant PWR Primary (Li/B d osed) water at 290 degrees C. Data analyses reveal that both plateau c orrosion fatigue crack propagation rate, da/dN(p), and threshold stres s intensity factor, Delta K-thp, are closely proportional to the squar e root value of bulk sulphur concentration in the range 0.003-to 0.019 %. These relationships have been supported by other sources of data ob tained under similar testing conditions. Available experimental result s also show that both da/dN(p) and Delta K-thp are linear functions of the difference between externally applied potential and open circuit potential, Delta E. An equation has been proposed to predict the syner gistic effect of sulphur content and applied potential on the plateau corrosion fatigue crack growth rate of A533B steels.