Magnetic particle inspection (MPI) is one of the most widely used NDT methods for detecting surface and near-surface discontinuities in ferromagnetic materials. Whether you are inspecting welds, castings, or forgings, selecting the right equipment directly affects detection sensitivity, operator efficiency, and compliance with applicable standards.

This guide covers the core equipment categories required to run a reliable MPI program, from portable yokes to stationary bench units, along with the consumables that support them.

How Magnetic Particle Inspection Works

MPI induces a magnetic field in the test part. When a flaw interrupts that field, magnetic flux leaks at the surface. Magnetic particles applied to the part collect at flux leakage areas, forming visible indications. The method detects cracks, seams, and laps that would otherwise be invisible, making it standard practice in aerospace, oil and gas, structural fabrication, and pressure vessel inspection.

Portable Electromagnetic Yokes

Electromagnetic yokes are the most common starting point for MPI programs. They are compact, available in AC or DC configurations, and designed for both field and shop use. Key specifications to evaluate include:

• Lifting force: ASME and AWS standards require a minimum 10 lb lifting force for AC yokes and 40 lb for DC yokes. Verify compliance before purchase.
• Power type: AC yokes provide stronger surface sensitivity; DC and permanent magnet yokes offer slightly deeper penetration.
• Leg articulation: Adjustable leg spacing accommodates curved or irregular part geometries.

Newco Inc stocks electromagnetic yokes suited for weld, casting, and structural inspection applications across a range of operating environments.

Stationary Bench Units and Power Packs

For production environments where throughput is a priority, stationary horizontal wet bench units and power packs offer an efficient alternative to portable equipment. These units magnetize parts through head shots, coil shots, or central conductor techniques, enabling inspection of complex geometries in a single setup.

Critical specifications include amperage output, contact head design, and demagnetization capability. High-output power packs in the 3,000 to 6,000 amp range serve aerospace and heavy industrial applications where procedures demand high magnetizing force. When standard configurations do not match your production requirements, Newco’s custom systems division can engineer a solution around your part dimensions and throughput specifications.

UV and White Light Equipment

Fluorescent MPI requires adequate UV-A illumination, typically a minimum of 1,000 microwatts per square centimeter as specified in ASTM E1444. Visible method inspection requires sufficient white light intensity. When selecting lamps, consider the following:

• UV-A output: Confirm 365 nm wavelength and intensity compliance with your applicable standard.
• Lamp technology: LED lamps provide instant-on operation and extended service life. Mercury vapor lamps require a warm-up period but remain in use at many established facilities.
• Portability: Battery-powered UV lamps support field inspection; fixed-mount configurations serve production lines.

Magnetic Particle Consumables

Equipment selection is only part of the equation. Consumable quality directly affects detection performance.

Wet method: Fluorescent or visible particles are suspended in a petroleum-based or water-conditioned carrier and applied to the magnetized part. Fluorescent particles provide higher sensitivity for fine discontinuities. Carrier concentration must be verified through bath certification procedures on a regular basis.

Dry method: Dry powder is applied to the part surface during active magnetization. This approach is well-suited for rough or elevated-temperature surfaces where wet suspension would be impractical.

Newco Inc supplies fluorescent and visible magnetic particles, carrier concentrates, and bath maintenance products from ISO-qualified manufacturers.

Applicable Standards and Documentation

Most MPI programs operate under one or more of the following industry standards:

• ASTM E1444 and E709 for general magnetic particle examination
• ASME Section V for pressure vessel and piping inspection
• AWS D1.1 for structural welding inspection
• NAS 410 and EN 4179 for aerospace certification requirements

Equipment must meet the performance requirements defined in your applicable procedure. Newco’s technical team can assist in matching equipment specifications to your procedure requirements and help ensure purchases are properly documented for your quality records.

Get the Right Equipment for Your MPI Program

Building or upgrading a magnetic particle inspection program requires the right combination of equipment, consumables, and technical expertise. Newco Inc offers a comprehensive selection of MPI equipment, from portable yokes to high-output bench units, along with the particles, carriers, and accessories to support your inspection operations.

Contact our team to discuss your application requirements, request technical specifications, or get a quote on magnetic particle inspection equipment for your facility.