Hydrogen Embrittlement and Corrosion Fatigue Performance of Galvanized Steel Wires for High Strength Bridge Cables

Abstract

The research results of mechanical properties, hydrogen embrittlement and corrosion fatigue of new and corroded galvanized wires which were used in cable-supported bridges were summarized. Actual tensile strength of corroded wires did not decrease with corrosion levels, whereas elongation and torsional strength decreased sharply after the zinc layer was partly depleted and the steel started to corrode. The accumulated amounts of diffusive hydrogen of corroded wires with and without induced tension were almost the same and were well below a critical value of 0.7ppm. Therefore, induced tensions of steel wires did not affect the amount of diffusive hydrogen and below the critical concentration to cause brittleness. Fatigue strength did not change only when the galvanized layer was corroded, but it significantly decreased after the steel corrosion below the galvanized layer progressed. The corrosion fatigue life under wet conditions was shorter than that under dry conditions. The endurance life of pre-split steel wires was decreased in stress amplitude and increased in load frequency under fluctuating loading and corrosive environment, the aggressive media accelerated the growth rate of the fatigue crack.