An improved design of high-signal-to-noise ratio spiral-coil EMAT for high-temperature defect detection

The study introduces an enhanced concentric spiral-coil EMAT to tackle low signal-to-noise ratio (SNR) in high-temperature carbon steel forging defect detection. With a non-overlapping concentric coil design, simulations and experiments were conducted, utilizing a finite element model with circuit-field coupling to optimize parameters. Results show the improved EMAT enhances SNR by up to 20.96 dB compared to traditional designs. High-temperature tests demonstrate its capability to detect Ф5 mm holes at 650℃, with SNR increasing by 11.24 dB as temperature rises from 100℃ to 500℃, validating the optimization method's effectiveness.