Alternating Current Field Measurement (ACFM) has long been recognized for its ability to perform fast, reliable inspections of welds in ferromagnetic and non-ferromagnetic materials, with minimal surface preparation and strong performance through coatings and in challenging environments. Building on this foundation, recent technological advancements have expanded the frontiers of what ACFM can achieve in the field of structural weld inspection.
This paper presents three groundbreaking ACFM-based inspection capabilities that address previously unresolved challenges in industrial asset integrity. First, we introduce a high-temperature ACFM probe capable of operating at surface temperatures up to 500°C (932°F), enabling accurate in-service inspection of hot components such as pipework and pressure vessels without the need for shutdowns. Second, we detail a new ACFM technique optimized for galvanized steel, which provides reliable detection and sizing of both surface and sub-surface cracks—even through conductive coatings up to 300 µm thick. Third, we unveil a robust, encoder-free array probe designed for efficient single-pass filet weld inspection. This solution integrates the novel 3BZ crack sizing method, eliminating the need for surface markings and enabling instant defect characterization.
Together, these innovations push the boundaries of electromagnetic inspection, enhancing productivity, reliability, and accessibility for a variety of complex inspection scenarios in energy, infrastructure, nuclear sectors.