Product Data Sheet – MAGNAVIS 7HF, WB-27
Visible Magnetic Inks
MAGNAVIS® 7HF and WB-27, our visible magnetic inks, are used for wet method magnetic particle testing of ferrous materials. They give clear black indications when viewed in daylight.
When used in conjunction with suitable magnetising equipment, MAGNAVIS 7HF and WB-27 will locate fine surface and slightly subsurface defects such as: shrink cracks, welding defects, grinding cracks, quenching cracks, and fatigue cracks.
Typical Properties (not a specification)
|Description||An oil-based, ready-to-use black ink.||A liquid concentrate used to prepare water-based black ink.|
|Composition||A suspension of magnetic particles in a high-flash petroleum distillate.||Black magnetic powder, wetting agent, defoamer and corrosion inhibitor.|
|Flash point||> 93°C (bulk product)||N/A|
|SAE sensitivity||6 – 7||6 – 7|
|Viscosity||2.5 mm²/s at 38°C||–|
|Density||0.8 g/cm³||1.4 g/cm³|
|Particle size range||0.2 – 2.0 µm||0.2 – 2.0 µm|
|Settlement volume (1 hour)||1.5 – 2.4 ml||1.5 – 2.4 ml|
|pH (2% solution)||Neutral||9.0|
|Storage temperature||10°C to 30°C||10°C to 50°C|
|Usage temperature||-5°C to 70°C||5°C to 80°C|
Like all Magnaflux materials, MAGNAVIS 7HF and WB-27 are closely controlled to ensure batch-to-batch consistency, optimum process control and inspection reliability.
General Method of Use
Clean the component before testing to reduce the risk of contamination and to provide a suitable test surface.
If the test surface is a dark colour, apply a thin coating of a suitable white contrast paint, such as MAGNAVIS WCP-2, to provide a contrasting background.
If using WB-27, make up the ink bath based on the guide volumes below (7HF is supplied ready-mixed so you can skip this step).
|Quantity of WB-27||Quantity of water|
|0.5 litres (500 ml)||25 litres|
|0.75 litres (750 ml)||37.5 litres|
|1 litre (1000 ml)||50 litres|
Before using, agitate the ink to ensure uniformity of mix and check the correct settlement volume (see ‘Typical Properties’ table above).
Apply the ink by spraying, flooding or immersion, depending on your chosen method:
Wet continuous method
Apply the ink to all surfaces of the component and apply a magnetising current. Remember to stop the flow of ink before the current is switched off, otherwise there is a risk that the force of the ink flood may wash away indications.
Wet residual method
This method is generally less sensitive than the continuous method and is more susceptible to rapid particle depletion and bath contamination.
- Pre-magnetise the part that needs to be tested.
- Imerse the part in a bath of the ink.
- Remove it and allow it to drain.
- Inspect the part.
Remember to agitate the ink regularly during use to ensure uniformity of mix. If you are using a bath and it appears contaminated, or if it has been in use for a long time, replace the contents.
During use, the magnetic content of any ink (except for aerosols) will become depleted so you will need to check your bath strength at least once each day. The most widely-used way of checking an ink’s settlement volume is by using a graduated ASTM pear-shaped centrifuge tube.
WB-27 only: if the settlement volume approaches the lower limit (see the ‘Typical Properties’ table above), you can add more WB-27 to the bath as long as it is still clean and uncontaminated.
After inspection, remember to completely demagnetise your components before cleaning, to ensure easy removal of any residual powder particles.
|AMS3043 (Aerosols only)||Yes||–|
|ASME B & PV Code, Sec V||Yes||Yes|
|EN ISO 9934-2||Yes||Yes|
|GOST R ISO 9934-2-2011||Yes||Yes|
Health & Safety
Read the relevant Safety Data Sheets for these products before use.
Part number 008A103
Part number 058C036