Flexible Field Magnetization for MT
The Yoke Method is a portable and practical Magnetic Particle Testing (MT) approach widely used for field inspections. It employs a handheld electromagnetic yoke—an iron core with adjustable legs and internal coil—that generates a magnetic field when energized (AC or DC), enabling detection of surface and near-surface discontinuities.
This method allows inspectors to magnetize only the localized inspection area, making it ideal for weld joints, structural steel, and confined zones where large equipment cannot be deployed. Depending on orientation, yokes can induce longitudinal or transverse magnetic fields for multi-directional flaw detection.
BQCIS field specialists use AC yokes for detecting surface cracks and DC yokes for enhanced penetration when identifying near-surface flaws. It can be performed using either dry powder or wet fluorescent techniques, offering high versatility for on-site testing.
Key Yoke Method Activities
Key Benefits of the Yoke Method
Highly Portable
Compact and easy to transport, suitable for remote or elevated work locations and complex structures.
Versatile Magnetization
Enables quick adjustment between longitudinal and transverse magnetic fields for comprehensive inspection coverage.
Multi-Method Compatibility
Compatible with dry visible, wet visible, or fluorescent magnetic particle media depending on site conditions and sensitivity requirements.
Cost-Effective & Efficient
Simple setup and affordable equipment make it ideal for rapid inspection cycles and daily field operations.
Success Story
Yoke MT Confirms Integrity of Bridge Weld Repair
Following a weld repair on a steel bridge girder, engineers required non-destructive verification to confirm the weld was free from cracks before reopening the structure to traffic.
BQCIS deployed a field technician equipped with an AC yoke and wet fluorescent particle system to perform on-site magnetic inspection of the weld repair zone.
The fluorescent indications under UV-A light confirmed no relevant discontinuities, validating the weld’s integrity and ensuring regulatory approval for immediate return to service.