锈蚀高强钢丝力学性能退化的试验研究

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

  • 摘要: 该文通过试验研究了锈蚀高强钢丝的锈蚀形貌、产物、力学性能,为其检测评估提供依据。用高分辨率X射线衍射仪和场发射环境扫描电镜分析高强钢丝锈蚀产物,用华朗-3DX+非接触式三维扫描仪确定其截面特性沿钢丝轴向的变化情况,还采用MTS试验机对其进行静力拉伸和疲劳加载试验。通过分析三维扫描数据确定锈蚀高强钢丝表面形貌,基于实测锈蚀高强钢丝力学性能建立本构关系模型参数与锈蚀率的退化关系。试验结果表明:高强钢丝锈蚀截面面积的变异性随锈蚀程度增加越来越显著;极限强度在锈蚀率大于1.25%时小于标准极限强度1770 MPa;断后伸长率在锈蚀率大于5.05%时小于规范限值4%;疲劳寿命在锈蚀率大于4.16%时小于200万次;锈蚀率对高强钢丝弹性模量无明显影响。根据试验结果综合完善了现有规范对锈蚀高强钢丝等级划分的指标值。

     

    Abstract: 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.

     

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