The Evaluation of Pulsed Eddy Current Technique of Surface Defect in Carbon Steel Welded Sample: Simulation Work

Pulsed eddy current (PEC) is an advanced non-destructive testing (NDT) method that uses electromagnetic induction with a rectangular waveform to examine surface defects. In this study, numerical simulations and experimental verification were conducted to characterize and quantitatively evaluate the PEC inspection of welded carbon steel samples. The simulations were performed using the time-stepping finite element method (FEM) in a 3D environment using COMSOL Multiphysics. The PEC behavior was observed on metallic samples (ferromagnetic) with two types of surface defects: longitudinal and transverse cracks (notch). Additionally, different defect depths (1 mm, 2 mm, 3 mm, 4 mm, and 5 mm) were investigated to analyze the impact of defect orientation and scanning direction on different regions of the welded carbon steel sample (base metal (BM), heat-affected zone (HAZ), and weld metal (WM)). The results showed that the conductivity of the specimens influenced the induced current density and the net magnetic field. To improve defect assessment and quantitative evaluation, a technique called differential peak value (PV) profiles (∆PV profiles) was proposed to evaluate the effect of different regions on the welded carbon steel samples. This technique enhances the accuracy of defect evaluation by isolating the defect signals from the influence of other regions. The findings of this study have practical applications in industrial weld inspection and other research areas.