• CN: 11-2187/TH
  • ISSN: 0577-6686

Journal of Mechanical Engineering ›› 2025, Vol. 62 ›› Issue (6): 228-236.doi: 10.3901/JME.260189

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A Non-Destructive Surface Hardness Testing Method Utilizing the Transduction Curve of a Magnetostrictive SH0 Guided Wave Sensor

YUAN Yuan1, Liu Xiucheng2, QI Pan3, Cao Wenbo1, Wang Zhenghong1, WU Bin2, Gao Xiang2   

  1. 1. College of Mechanical&Energy Engineering, Beijing University of Technology, Beijing 100124;
    2. College of Information Science and Technology, Beijing University of Technology, Beijing 100124;
    3. China Research Institute of Nuclear Power Operation, Wuhan 430223
  • Received:2025-05-05 Revised:2025-09-25 Published:2026-05-12

Abstract: Hardness is one of the core indicators of the mechanical properties of metallic materials. Traditional destructive testing methods are often inadequate for meeting the requirements of structural integrity and high-efficiency inspection in complex service environments. A non-destructive surface hardness evaluation method for ferromagnetic materials is proposed based on the transduction efficiency curve of a magnetostrictive SH0-mode guided wave sensor. An experimental system with a self-developed electromagnetic acoustic transducer (EMAT) is firstly constructed and then the excited and received SH0 guided wave signals under different bias magnetic field intensities are measured. Subsequently, the variations of the amplitude of guided waves with magnetic field intensity are determined to plot transduction response curves. Finally, representative characteristic parameters, including maximum amplitude AMax, mean amplitude AMean, and amplitude difference ∆A, are extracted to characterize the magnetoacoustic transduction behavior of the material. The transduction curve profiles and characteristic parameters differed significantly among specimens with varying hardness levels. Further analyses revealed the strong linear correlation between specific parameters and material hardness. AMax, AMean, and ∆A exhibited the consistent trends and good regional adaptability. These parameters could be used as highly reliable non-destructive indicators for hardness evaluation. This method achieved the non-contact, highly sensitive, and quantitative hardness assessment and offered a novel approach for the non-destructive evaluation of the hardness of ferromagnetic materials.

Key words: non-destructive testing, magnetostrictive effect, electromagnetic acoustic transducer, sensor transduction curve, hardness prediction model

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