Magnaflux Y-7 AC/DC Electromagnetic Yoke

Portable AC/DC yoke for magnetic particle inspection of welds in the field

The Magnaflux Y-7 is a hand-held electromagnetic yoke used to magnetise ferromagnetic parts during magnetic particle testing (MT). The yoke is placed across the area to be inspected, magnetic flux flows through the part between the two legs, and any crack or other discontinuity that interrupts the flux leaks a field that holds magnetic particles in place as a visible indication. The manufacturer describes the Y-7 as a durable, high-strength AC/DC magnetic yoke built to find surface and sub-surface indications in rugged applications.

Two features define the tool. First, solid-state controls let the operator pick AC fields for surface indications or DC fields for sub-surface indications, so one yoke covers both inspection tasks. Second, the sealed, chemical-resistant body has articulating legs that follow part contours. The data sheet names weld inspection and other remote testing as the typical use, and lists spot inspections, in-service inspections and demanding environments.

Key features from the manufacturer data sheet

• Sealed, durable, chemical and abrasion resistant construction
• AC and DC operation options: AC for surface indications, DC for sub-surface indications
• Articulating legs that contour to different part shapes, with a 0 to 12 in (0 to 30 cm) leg span
• Exceeds ASTM lifting specifications (as stated by the manufacturer)
• Strain-relieved cord for field use and an individual serial number on each yoke
• Defect types named: inclusions, seams, shrink cracks, tears, laps, welding slag, grinding cracks, quenching cracks and fatigue cracks

Technical specification

Derived value, not printed by the maker: an 80 second maximum on time at a 33 percent duty cycle works out to roughly 160 seconds of rest per full on period, so plan inspection sequences with breaks rather than continuous energising. The product page text mentions a twelve-foot cord while the property table gives 10 ft / 3.0 m; confirm the cord length for your unit before ordering.

Selection and ordering guide: voltage, plug and kit

Four part numbers are printed in the data sheet. Choose the voltage that matches the site supply first, then decide between the bare yoke and the test kit.

The data sheet adds a note that the Y-7 does not carry a CE mark and is not labelled to EU standards, so it cannot be shipped to EU countries. The 230V versions list no plug, so the supply connection must be arranged to suit the local socket. Give the part number and delivery country when requesting a quotation.

Operation and handling notes

The sheet gives no step-by-step procedure for the yoke itself, so follow your written MT procedure and the instruction manual that comes with the unit. General practice, not taken from the data sheet: clean the area, apply the particles or contrast paint, energise the yoke with the legs positioned so that the flux crosses the expected defect direction at close to right angles, and then repeat with the legs turned 90 degrees to cover both directions.

Respect the duty cycle, keep the legs seated flat on the part, and use the Yoke Test Weight listed in the sheet to confirm lifting capacity at the intervals your procedure sets.

Where the Y-7 fits in oil, gas, power and fabrication work

A portable yoke is the standard tool where parts cannot be brought to a bench: pressure-vessel and storage-tank welds, pipe spools, structural steel, crane and lifting-gear checks and in-service inspections during shutdowns. In Gulf conditions the sealed, chemical-resistant body is relevant to dust, heat and cleaning solvents, but check the unit against your site rules before use in any classified hazardous area, since the data sheet prints no hazardous-area rating.

Related consumables and accessories

Magnetic particle work with the Y-7 normally pairs the yoke with a particle suspension or powder and, in visible-light work, white contrast paint. See our other Magnaflux MT pages for 7HF visible aerosol, 14AM fluorescent suspension and 20B fluorescent premix, and the wider NDT Accessories range for related inspection equipment.

Frequently asked questions

Can the Y-7 find sub-surface defects?

The manufacturer states that DC fields are used for sub-surface indications and AC fields for surface indications, with defect location given as surface and subsurface.

What power supply does the Y-7 need?

The data sheet lists 115V at 60 Hz drawing 6.0 A, and 230V at 50/60 Hz drawing 2.7 A.

What is the duty cycle?

33 percent, with a maximum on time of 80 seconds.

Is the Y-7 CE marked for EU shipment?

No. The data sheet says the Y-7 does not carry a CE mark and cannot be shipped to EU countries.

Which accessories does Magnaflux recommend?

The Yoke Test Weight PN 077030 and the Yoke Light PN 623745.

Documents and quotation

The official product data sheet is attached to this page. Specifications on this page follow that sheet; always confirm voltage, plug and kit contents against the part number you intend to order. Seven Star LLC is an independent supplier based in Muscat. Request a quotation with the part number and quantity.