Fatigue fracture behavior of high-strength low-alloy steel for flexible marine riser in the high cycle fatigue regime

Abstract The relationship between microstructure, stress ratio, and fatigue fracture behavior of high-strength steel for flexible marine risers was investigated by microstructure characterization test. characteristic, S-N curve, morphology, crack morphology after quenching tempering treatment cyclic heat treatment, respectively, were evaluated. results revealed that the refined considerably, grain boundary density content high-angle increased, which inhibited propagation improved strength. average increased increasing promoted initiation propagation; consequently, strength life tested decreased.