Fatigue Properties Investigation of Corroded High-Performance Steel Specimens

Abstract

Experiments were performed to investigate the fatigue properties of corroded high-performance steel (HPS). Ninety pieces of Q460D and 90 pieces of Q550E HPS specimens with five different corrosion levels were designed to investigate the effect of corrosion on their fatigue properties. Three-dimensional (3D) scanning and scanning electron microscope (SEM) were employed to observe the macroscopic and microscopic morphology. The S-N curves in terms of various levels of corrosion damages were obtained, and the influences of different corrosion levels on the fatigue properties are discussed. The experimental results show that corrosion changes the characteristics of the fatigue crack source zone, crack development zone, critical transition zone, and instantaneous fracture zone. Compared with Q460D, the critical transition area of Q550E has a higher flatness. Progressing corrosion damage results in a linear decreasing fatigue life of the HPS specimens in the double logarithmic coordinate system. The fatigue life of steel specimens can be expressed as an exponential function of the cross-sectional corrosion loss level. The increasing stress level will aggravate the degradation of fatigue life.