Influences of Stress Cycle Frequency and Stress Ratio on Corrosion Products-induced Wedge Effects

概要

論文の詳細を見る
The corrosion fatigue crack growth rate of a high tensile strength steel HT55 has been measured in 1% NaCl solution at various stress cycle frequencies and stress ratios to elucidate the corrosion product-induced wedge effect and dominating mechanical parameters for crack growth. The wedge effect is greatest at R = 0.1, whereas it is less great in the order of R = -1 and R = 0.5. At R = -3, however, the wedge effect disappears, and the growth rate is higher in 1% NaCl solution, the load-strain hysteresis loop traces different paths during loading and unloading periods, resulting from viscosity of the corrosive solution remaining within cracks, but the load sharing capacity of the viscosity is negligibly small. Regions I and II in the hysteresis loop must be taken into consideration to explain uniquely the corrosion fatigue crack growth characteristics under various conditions, and a contributory stress intensity factor range ΔK_<cont>is proposed as a difference between ΔK and ΔK<ret>, deduced from the load range shared by regions I and II.
一般社団法人日本機械学会の論文