Magnetic Particle Testing
- Overview
- Aerosol detection media
- Coloured detection media
- Fluorescent detection media
- Background colour
- Cleaner
- Test oils and conditioning agents
- Test bodies and reference blocks
- Test kit and accessories
- Hand yoke magnets
- Accessories for hand yoke magnets
- Permanent magnets
- Mobile equipment
- High current generator / accessories
- Magnetising coils
- MT test facilities
- UV LED lamps
- UV(A) protective goggles
HELLING GmbH
Since 1863
Magnetic particle testing
Magnetic Particle Testing
Magnetic particle inspection is a simple but sensitive method for detecting irregularities in the surface of ferromagnetic materials with a relative permeability µr >100, e.g. steel, cast iron, cobalt, nickel. Inhomogeneities close to the surface can also be detected. The depth of detectable indications depends on the field used:
- Alternating field max. 1 mm - 2 mm
- DC field max. 2 mm - 3 mm
Surface crack inspection with the fluorescent magnetic particle testing - the crack indication is clearly visible under UV irradiation
Weld seam testing with the magnetic particle testing with coloured (here black) suspension and white background colour (black-white method)
During magnetisation of the ferromagnetic material, leak fluxes occur over material separations (e.g. cracks, pores). The detection can be performed
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HELLING offers various detection media (fluorescent or coloured) in the form of
- Dry powder
- Liquid water-based concentrate
- Ready-to-use oil-based suspension
MT detection media for magnetic particle testing (aerosols) - fluorescent or coloured suspensions based on water or oil
White background colour to improve contrast and cleaner for pre- and final cleaning
HELLING develops test facilities like
- Hand yoke magnets
- Cross yokes
- Permanent magnets
to generate the magnetic field. These are manufactured at HELLING and can thus be optimally adapted to the customer's test conditions.
Hand-held yoke magnet for magnetisation, e.g. for non-destructive testing of a weld seam with magnetic particle testing
Test bodies and reference blocks according to international standards enable the detection media to be checked in accordance with the standards.
Reference blocks for magnetic particle testing to check the indication sensitivity of the detection media (magnetic particle suspension)
Furthermore, HELLING manufactures fully equipped testing systems for magnetic particle testing according to customer-specific requirements. This includes for example
- Crack testing benches of different sizes
- Railway wheelset testing facilities
- Test tables for testing cylindrical, rectangular or irregularly shaped test specimens
- Test benches for serial testing
- Test benches for training purposes
Wheelset testing system ROD-A-MAT for combined testing of wheelset axle and wheelset wheels with fluorescent magnetic particle testing
Aerosol detection media
Test equipment in spray cans is mainly used for quick and efficient testing in mobile applications.
The aerosol suspensions - both oil-based and water-based - are characterised by high sensitivity. They therefore allow the detection of the finest cracks.
Weld seam testing with black magnetic powder suspension BW 333 and white background colour NR 104 A spray
The low consumption and the handiness of the aerosol can make them ideal for use on construction sites or for quick testing of individual test parts.
Aerosol test equipment from Helling meets the requirements of
- ASME Code Section V
- ASTM E709
- DIN EN ISO 9934
Coloured detection media
In addition to fluorescent detction media, the Helling GmbH product range includes a diverse range of coloured test products in the form of
- Dry powders
- Concentrates
- Ready-to-use suspensions
The coloured magnetic powders are characterised by their
- brilliant colour
- defined particle size distribution
- High purity
They produce easily recognisable indications on both dark and blank, bright surfaces.
The water-suspended and dry magnetic powder concentrates for the preparation of ready-to-use water-based suspensions already contain
- Rust inhibitor
- Wetting agent
- Defoamer
They are therefore also used for testing corrosion-sensitive parts.
The use of concentrates contributes significantly to the reduction of transport and storage costs.
Ready-to-use oil-based suspensions are ideal for use on construction sites or for manual testing of individual test parts. The test oils to be used are colourless, odourless and skin-compatible. They have a low viscosity. As a result, the finished suspensions have only short dripping times.
The product range also includes ready-to-use suspensions in spray cans for fast, efficient testing in mobile applications.
Helling test products meet the requirements of
- ASME Code Section V
- ASTM E709
- DIN EN ISO 9934
Fluorescent detection media
For the performance of magnetic particle testing under UV-A irradiation Helling GmbH offers a range of fluorescent detection products in the form of
- Dry powders
- Concentrates
- Ready-to-use suspensions
The fluorescent magnetic powders are characterised by
- High fluorescence coefficient
- Defined particle size distribution
- Hhigh purity
They produce indications that are easily recognisable under UV irradiation. The finest cracks are detectable.
The water-suspended and dry magnetic powder concentrates for the preparation of ready-to-use water-based suspensions already contain
- Rust inhibitor
- Wetting agent
- Defoamer
They can also be used for test objects that are sensitive to corrosion.
The use of concentrates contributes significantly to the reduction of transport and storage costs.
Ready-to-use oil-based suspensions are ideal for use on construction sites or for manual testing of individual test parts. The test oils to be used are colourless, odourless and skin-compatible. They have a low viscosity. As a result, the finished suspensions have only short dripping times. Because the test oils do not exhibit any inherent fluorescence, high-contrast, brilliant crack indications are produced.
The product range also includes ready-to-use suspensions in spray cans for fast, efficient testing in mobile applications.
Helling test products meet the requirements of
- ASME Code Section V
- ASTM E709
- DIN EN ISO 9934
Background colour
Cleaner
Test oils and conditioning agents
Test bodies and reference blocks
Test kit and accessories
Hand yoke magnets
Series HANSA is the new generation of hand yoke magnets, which is characterised by several advantages over the previous series: the yokes are
- of lower weight
- handy
- more powerful
An important ergonomic feature of the HANSA series is the narrow handle bar, which allows fatigue-free work - even for small hands - over a long period of time.
The HANSA series consists of the hand yoke magnets
- UM-8
- UM-9
- UM-10
- UM-15
All hand yoke magnets are manufactured at Helling GmbH.
The UM-8, UM-9 and UM-10 hand yoke magnets differ in the following ways
- the dimensions (mean pole spacing and leg length)
- the weight
- the pull-off force
The pole spacing can be changed by attaching attachment poles. The lower leg of the 45° attachment pole can be swiveled inward or outward by 45°, for example. This increases or decreases the pole distance. The 45° bevel of the contact surface of the attachment pole allows optimum adaptation to the respective test object geometry.
Flexible pole 45°
For use in harsh conditions, the hand magnets can be equipped with protective poles.
Hand yoke magnet UM-15 is equipped with three-link movable legs as standard. These can be used to set pole distances (center/center) from 95 mm to 245 mm.
In relation to
- Lifting force
- Tangential field strength
all hand yoke magnets of the HANSA series meet the requirements of the current standards and regulations such as
- EN ISO 9934-3
- ASTM E709
- ASME Code Section V
The hand yoke magnets of the HANSA series are fully potted and thus meet protection class IP 65.
They are available in the following mains voltage versions:
- 230 V
- 110 V
- 42 V (with transformer)
With the exception of UM 8 (60 s, 30% ED), they can be used with a maximum on-time of 150 s and a maximum duty cycle (ED) of 50%.
The power cable can be unscrewed. This prevents malfunctions and costly repairs due to kinked cables directly at the cable entry.
Greater mobility and freedom of movement are provided to the test personnel by the battery-powered and thus network-independent DC hand-held yoke magnets of the HANSA-DC series.
Here, too, a low weight, the narrow handle bar ensure fatigue-free work. The surface of the devices is slightly roughened, which prevents slipping in the hand.
The magnets are powered by a compact NiMH battery of high capacity and long operating time. The battery charge status is indicated by the LED operation indicator integrated in the yoke housing.
The HANSA-DC hand yoke magnets meet the requirements of
- ASTM E709-21
- ASTM E1444/E1444M-21
The pull-off force is >27 kg / >265 N. Thus, the requirement of ASTM E 709-21 (at least 23.0 kg / 225 N) is fulfilled.
OPTIONAL test reports are available for all HANSA manual yoke magnets.
Accessories for hand yoke magnets
Inductive UV or white light LED light frames are used when working with hand yoke magnets or cross yokes. The LED light frames are independent of the mains connection. They allow simultaneous irradiation by UV LED and illumination by white light LED. In this way, the test area is illuminated and/or irradiated in accordance with standards during materials testing with fluorescent or coloured magnetic powders. In addition, the test personnel has one hand free because he does not have to operate a separate LED light.
With the swiveling head of the illuminated frame, the irradiation or illumination angle can be adjusted according to the pole spacing and limb length so that an optimally illuminated homogeneous irradiation or illumination area is obtained in the center of the test area.
Crack detection with hand-held yoke magnet and UV-LED light frame using a fluorescent magnetic powder suspension
The light frames are powered by induction current during magnetization and thus require neither battery nor mains connection.
Light frames are particularly useful for testing in confined spaces, on construction sites and improvised testing conditions where there are only limited suitable storage facilities for testing aids.
The jet-proof light frames (IP 65) can be used for all hand-held magnets with pole dimensions of less than 50 mm x 50 mm. They are quickly and easily attached to the base of the hand magnet by means of two plastic screws.
Permanent magnets
Mobile equipment
High current generator / accessories
Magnetisation coils
MT test facilities
UV LED lamps
Fluorescent detection media are also used in magnetic particle testing. These are more sensitive than colour contrast penetrants, e.g. in the so-called black-and-white method.
UV LED lamps are used to make the indications visible.
HELLING UV LED hand lamp UV-Inspector 711 IP65 for use in fluorescent magnetic particle testing
HELLING is a leading company in the development of handheld UV LED lamps and UV LED stationary lamps.
You can find the actual products here...
UV(A) protective goggles
UV LED lamps are used for the inspection of fluorescent indications (in penetrant or magnetic particle testing). To protect the eyes of the NDT personnel from the harmful UV(A) radiation, the use of UV(A) protective goggles is essential.
UV protective goggles
Type Millennia
UV protection glasses you can find here...
