增减材复合制造内部缺陷的涡流检测

Eddy current testing of internal defect in additive/subtractive hybrid manufacturing

涡流检测(ECT)技术具有非接触、无需耦合剂、检测灵敏等特点,适用于加工环境较为特殊的增减材复合制造(ASHM)中。本文建立了无缺陷半无限大试样内部涡流分布的解析模型,开展了预制人工缺陷的钛合金增材试样检测实验,研究了ECT深度与激励频率、提离量之间的关系。理论分析与实验结果均表明,内部缺陷较深时,低激励频率条件下缺陷产生的电抗增量信号较大,不同提离量下的电抗增量信号相差不大,因此检测位置较深的内部缺陷时可采用较低的激励频率并适当提高提离量。在本文实验条件下,ECT最佳激励频率为90kHz;提离量增加到0.97mm时,有效检测深度略有减小。这一结论可为ECT技术与ASHM的集成提供理论依据。

Eddy Current Testing(ECT)technology is suitable for the complex processing environment of Additive/Subtractive Hybrid Manufacturing(ASHM)due to its non-contact,couplant-free and high-sensitive features.An analytical model is established to calculate the internal current distribution of the semi-infinite sample without defects.A titanium alloy sample with internal artificial-defects is fabricated by ASHM and the ECT experiments are conducted on it to study the effect of the excitation frequency and the lift-off distance on the testing depth.Both the theoretical and experimental results show that for a deep internal defect,a lower excitation frequency leads to a larger reactance increment signal and the lift-off distance has little effect on the reactance increment signal.The study concludes that the optimal excitation frequency of ECT is 90kHz,and the optimal lift-off distance is 0.97mm.The conclusion provides a theoretical foundation for the integration of ASHM and ECT.