Abstract

During operation, the surfaces of parts made of austenitic chromium–nickel steels are subjected to intense cyclically repeated contact loads, including shock loads. Therefore, an urgent task is to study contact fatigue and develop methods for nondestructive testing of fatigue degradation of such steels. The aim of this work is to study the possibility of conducting eddy current testing of fatigue degradation under contact loading of AISI 321 austenitic steel. Mechanical tests for contact gigacycle fatigue were carried out according to the scheme of a pulsating shock “plane-plane” contact with an ultrasonic loading frequency. It is shown that eddy current monitoring of fatigue degradation under contact loading of AISI 321 steel is possible, but it has certain limitations due to the nonmonotonic change in the readings of the eddy current device \(\alpha \) vs the number of loading cycles. In this case, the ascending branch can be used to control the degree of destruction of the surface layer by taking into account the ambiguous nature of the dependences of the readings of the eddy current device on the number of loading cycles in the inspection procedure. The inspection can be carried out by taking the readings of the eddy-current device at the eddy-current transducer excitation frequency \(f = 124\) kHz. In this case, the surface layers, where the fatigue degradation processes develop intensively affecting the physical characteristics of the steel, are analyzed to a greater extent. The quantitative ratio of austenite and deformation martensite in the testing zone has the greatest effect on the value of \(\alpha \).

中文翻译：

---

万级接触疲劳载荷下亚稳态奥氏体钢疲劳降解的涡流检测

摘要

在操作过程中，由奥氏体铬镍钢制成的零件表面会承受强烈的循环重复接触载荷，包括冲击载荷。因此，当务之急是研究接触疲劳并开发此类钢疲劳退化的无损检测方法。这项工作的目的是研究在接触载荷下对 AISI 321 奥氏体钢进行疲劳退化涡流测试的可能性。根据脉冲冲击“平面-平面”接触与超声加载频率的方案，进行了接触千兆周疲劳的机械测试。结果表明，AISI 321钢接触载荷下疲劳退化的涡流监测是可能的，但由于涡流装置读数的非单调变化，它具有一定的局限性\(\alpha \) vs 加载周期数。在这种情况下，通过考虑涡流装置的读数对检查程序中加载循环次数的依赖性的模糊性质，可以使用上升分支来控制表面层的破坏程度。可以通过在涡流传感器激励频率\(f = 124\) kHz 下读取涡流装置的读数来进行检查。在这种情况下，在更大程度上分析了疲劳退化过程严重影响钢的物理特性的表面层。试验区奥氏体与变形马氏体的定量比对\(\alpha \)值的影响最大.