Application of the Methods of Mechanical Resonance for the Detection of Defects in Steels of Steam Pipelines After Operation

作者：Vdovychenko O V^*

来源：Materials Science, 2014, 49(4): 461-468.

DOI：10.1007/s11003-014-9637-3

• steel of steam pipelines
• internal friction
• nonlinear resonance methods

We use linear and nonlinear methods of mechanical resonance to detect defects in steels after operation for similar to 7 center dot 10(4) - 2.45 center dot 10(5) h in steam pipelines of a thermoelectric plant. We determine the sound velocity, vibration decrement, its dependence on the amplitude of maximum cyclic stresses, and the dependence of the resonance frequency of a cantilevered rod specimen on the strain amplitude. It is shown that the vibration decrement of materials after operation is higher than in the as-delivered state and its dependence on the stress amplitude becomes stronger. It is found that the material after operation is characterized by the nonlinear elastic behavior, which manifests itself as a distortion of the resonance curve and in the form of dependence of the resonance frequency on the amplitude. We establish a linear dependence of the resonance frequency on the strain amplitude, which is in good agreement with a similar dependence of the vibration decrement. We confirm that the nonlinear methods are promising for the detection of defects in steam pipelines.

• 出版日期2014-1