Influence of galvanization on the corrosion fatigue performance of high-strength steel

This paper introduces a systematic methodology providing insights to the corrosion fatigue behaviour of high-strength steel C-ring specimens, through the development of an appropriate, fully automated, corrosion fatigue device. The apparatus is capable of adjusting the cyclic load and frequency applied on the specimens, whilst being submerged in a corrosive solution. A 3.5% NaCl solution was used as the corrosive medium for the purpose of this investigation, for both galvanized and uncoated specimens, as to quantify the effect of the coating on their fatigue response. The experimental process was simulated through Finite Element Modelling (FEM) to determine in-situ stress fields and elucidate crack propagation. The applied galvanizing process facilitated a prolongation of the corrosion fatigue endurance of the tested high-strength steel, allowing it to withstand a fourfold increased number of cycles to failure, when compared to the uncoated samples under identical conditions. The fractured surfaces of the specimens indicate a different failure mechanism for galvanized and uncoated high-strength steel.