ANALXSIS OF FATIGUE FRACTURE WITH CYCLIC OVERLOADING FOR A537 STEEL IN 3.5%NaCl SOLUTION AT AN APPLIED CATHODIC POTENTIAL
3.5%NaCl中阴极极化下A537钢间歇超载疲劳断品分析

The fatigue crack propagation rate has been measured for A537 steel in 3.5%NaCl solution at an applied cathodic potential of -1400mV(SCE) under different cyclic overload occurrence ratio(OCR). The fracture surface characteristics have been analyzed by SEM. When OCR=10-l and 10-2, the crack growth was accelerated and some brittle characteristics such as cleavage and intergranular cracking were observed on the fracture surface. However, for OCR=10-3,2×10-4 and 10-4, the crack growth was retarded, and the pearlite morphology appeared on the fracture. The difference of cracking models between ferrite and pearlite in A537 steel could be the enrichment of hydrogen atoms at the interphase of ferrite and cementite.