EXPERIMENTAL STUDY ON DEGRADATION OF MECHANICAL PROPERTIES OF CORRODED HIGH STRENGTH STEEL WIRE

The morphology, product and degradation of corroded high strength steel wire were tested, which was essential for inspection and mechanical evaluation. The corrosion products were analyzed by high resolution X-ray diffractometer and environmental scanning electron microscope. Three-dimensional scanning was applied to determine the change of the cross section of corroded wire along the axial direction. Static tensile and fatigue loading tests were also carried out. The corrosion morphology of high strength steel wire is determined by the analysis of 3D scanning data. The degradation of the constitutive model parameters of corroded high strength wires are derived by the regression analysis of the test mechanical parameters and corresponding corrosion ratios. The test results show that: the variability of sectional area along wire axis increases with the increase of corrosion degree, the ultimate strength of corroded wire is less than the standard strength of 1770 MPa when corrosion ratio is more than 1.25%; the elongation is less than the specification limit of 4% when the corrosion ratio is greater than 5.05%; the fatigue life is less than 2 million cycles when the corrosion ratio is more than 4.16%; while corrosion has little effects on the elastic modulus. The index for evaluation of corroded wire is refined for the specification based on the above results.