Description
Flexible Laminated Strips (Type I) play a crucial role in detecting induced magnetic fields during magnetic particle inspections of various engineering components. These magnetic flux indicator type i indicators provide valuable insights into the direction and strength of a magnetic field. They are meticulously designed to respond specifically to the tangential component of the ‘H’ field in the air above magnetized workpieces.
These indicators are highly versatile and can offer a semi-quantitative estimate of field strength when the workpiece is magnetized using the current flow technique with alternating current. However, it’s essential to note that when different magnetization methods, such as a coil, are employed, a magnetic field is generated in the air. In such cases, the indicator will respond to this field, whether or not a ferromagnetic item is present.
To use these indicators correctly, follow these four key steps:
- Attach one indicator to the workpiece, aligning its long axis with the expected defect’s direction.
- Affix a second indicator perpendicular to the first.
- Magnetize the workpiece using standard procedures and apply magnetic particles.
- Allow for a minimum of 3 seconds of magnetization to enable particle migration before inspecting the indicators.
These foil-type indicators are well-suited for a wide range of engineering applications, both critical and general. They serve as invaluable guides for determining magnetic field direction and estimating field strength across magnetized surfaces. Designed in compliance with applicable customer standards, these indicators are ideal for Magnetic Particle inspections.
Interpreting the results:
- If one indicator clearly displays indications while the other does not, it indicates that the induced magnetic field’s direction is at a right angle to the indicator showing indications.
- If both indicators display indications, the induced magnetic field’s direction lies between the two indicators. The diffuse nature of the indications at the ends can help deduce the field’s direction. In such cases, consider repositioning the indicators to achieve differential results after re-applying magnetic particles and magnetization.
- If neither indicator shows indications, several possibilities exist. Commonly, this may indicate insufficient induced magnetic field strength in the material for magnetic particle inspection to proceed or the absence of an external field, which can occur in circular magnetization.
It’s important to note that assessing field strength is possible only when alternating current is used. To estimate field strength effectively, mount the indicators vertically, allowing magnetic ink to drain readily. When all three indications are clearly visible, you can estimate that the induced field in the air above the workpiece’s surfaces exceeds 2000 Amp/meter. Mounting the indicators horizontally does not allow for an assessment of field strength.
