NM01PIEGAUGE
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Magnafield Pie Gauge | Magnetic Field Indicator
The Standard for Verifying Magnetic Field Direction and Strength
The Magnafield Pie Gauge is an essential NDT tool used to provide a visual representation of the magnetic field during the inspection of ferromagnetic parts. While it is not used to quantify the strength of the field (like a Gauss meter), it is the primary method for ensuring that the magnetic flux is flowing in the correct direction to reveal defects. By placing the gauge on the workpiece and applying magnetic particles, the inspector can instantly confirm the orientation and "health" of the magnetic field.
Key Performance Features
Precision Construction: Consists of eight triangular segments of highly permeable material (low-carbon steel) furnace-brazed together to form a "pie" shape.
Artificial Discontinuities: The copper-plated surface conceals the internal seams between the segments. These seams act as artificial discontinuities that the magnetic field must bridge.
$360$° Field Verification: Because the segments create eight distinct paths, the gauge can indicate the direction of the magnetic field regardless of its orientation—critical for ensuring the field is perpendicular to suspected cracks.
Rugged & Portable: Compact, lightweight, and plated for corrosion resistance, making it suitable for both laboratory and harsh field environments.
Standard-Compliant: Manufactured to meet the exact dimensions and material specifications required by international NDT codes.
Technical Specifications
| Feature | Specification |
| Material | Low Carbon Steel (Eight Segments) |
| Coating | Protective Copper Plating |
| Standard Compliance | ASTM E709, ASTM E1444, ASME Section V |
| Indication Type | Visual (Pattern formation with particles) |
| Dimensions | Standard 1" (25.4 mm) Diameter |
How to Use the Pie Gauge
Place the Pie Gauge on the part being inspected, with the copper side facing up.
Apply the magnetic field (via Yoke, Prods, or Coil).
Apply magnetic particles (dry or wet) to the copper surface.
Observe the pattern. A clear cross-pattern of particles indicates a strong magnetic field. The lines that are most distinct will be perpendicular to the direction of the magnetic flux.
Ideal Applications
Field Inspection: Verifying the field of an AC/DC Yoke on-site.
Bench Units: Ensuring proper circular or longitudinal magnetization.
NDT Training: An excellent visual aid for teaching the principles of magnetic flux and particle movement.
Expert Insight: Remember that the Pie Gauge is a field direction indicator, not a calibration tool for field strength. To measure actual flux density in Gauss or Tesla, you should pair this tool with a calibrated Digital Hall Effect Gauss Meter.