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UMC 25x6/4x8 / N38 - cylindrical magnetic holder

cylindrical magnetic holder

Catalog no 320408

GTIN/EAN: 5906301814641

Diameter

25 mm [±1 mm]

internal diameter Ø

6/4 mm [±1 mm]

Height

8 mm [±1 mm]

Weight

21 g

Load capacity

14.00 kg / 137.29 N

Coating

[NiCuNi] Nickel

11.70 with VAT / pcs + price for transport

9.51 ZŁ net + 23% VAT / pcs

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Specifications along with structure of a magnet can be tested with our magnetic mass calculator.

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Technical data - UMC 25x6/4x8 / N38 - cylindrical magnetic holder

Specification / characteristics - UMC 25x6/4x8 / N38 - cylindrical magnetic holder

properties
properties values
Cat. no. 320408
GTIN/EAN 5906301814641
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
Diameter 25 mm [±1 mm]
internal diameter Ø 6/4 mm [±1 mm]
Height 8 mm [±1 mm]
Weight 21 g
Load capacity ~ ? 14.00 kg / 137.29 N
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±1 mm

Magnetic properties of material N38

Specification / characteristics UMC 25x6/4x8 / N38 - cylindrical magnetic holder
properties values units
remenance Br [min. - max.] ? 12.2-12.6 kGs
remenance Br [min. - max.] ? 1220-1260 mT
coercivity bHc ? 10.8-11.5 kOe
coercivity bHc ? 860-915 kA/m
actual internal force iHc ≥ 12 kOe
actual internal force iHc ≥ 955 kA/m
energy density [min. - max.] ? 36-38 BH max MGOe
energy density [min. - max.] ? 287-303 BH max KJ/m
max. temperature ? ≤ 80 °C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C
properties values units
Vickers hardness ≥550 Hv
Density ≥7.4 g/cm3
Curie Temperature TC 312 - 380 °C
Curie Temperature TF 593 - 716 °F
Specific resistance 150 μΩ⋅cm
Bending strength 250 MPa
Compressive strength 1000~1100 MPa
Thermal expansion parallel (∥) to orientation (M) (3-4) x 10-6 °C-1
Thermal expansion perpendicular (⊥) to orientation (M) -(1-3) x 10-6 °C-1
Young's modulus 1.7 x 104 kg/mm²
Engineering data and GPSR
Elemental analysis
iron (Fe) 64% – 68%
neodymium (Nd) 29% – 32%
boron (B) 1.1% – 1.2%
dysprosium (Dy) 0.5% – 2.0%
coating (Ni-Cu-Ni) < 0.05%
Environmental data
recyclability (EoL) 100%
recycled raw materials ~10% (pre-cons)
carbon footprint low / zredukowany
waste code (EWC) 16 02 16
Safety card (GPSR)
responsible entity
Dhit sp. z o.o.
ul. Kościuszki 6A, 05-850 Ożarów Mazowiecki
tel: +48 22 499 98 98 | e-mail: bok@dhit.pl
batch number/type
id: 320408-2026
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Magnet pull force

Field Strength

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They are characterized by point action of the magnetic field exclusively on the front surface. Thanks to side shielding, they do not "catch" the walls of the mounting hole, which facilitates installation.
These holders usually have an internal thread (blind or through) on the back wall. The mounting thread allows for stable and secure fixing in a machine or jig.
All magnet energy is directed exclusively to the front (active surface), increasing point force. It increases attraction force in the magnet axis and facilitates assembly in ferromagnetic blocks.
The steel housing provides excellent mechanical protection for the brittle magnet against impacts. Thanks to the solid build, the holder withstands repeated impacts and shocks during work cycles.
We recommend making the mounting hole with slight clearance and using glue for certainty. For mounting certainty and centering, gluing or screw fastening from the back is used.

Pros as well as cons of neodymium magnets.

Advantages

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:
  • They virtually do not lose strength, because even after 10 years the decline in efficiency is only ~1% (according to literature),
  • They are noted for resistance to demagnetization induced by external disturbances,
  • In other words, due to the aesthetic layer of silver, the element looks attractive,
  • Magnets possess impressive magnetic induction on the active area,
  • Neodymium magnets are characterized by very high magnetic induction on the magnet surface and can work (depending on the form) even at a temperature of 230°C or more...
  • Thanks to flexibility in designing and the ability to adapt to specific needs,
  • Wide application in modern industrial fields – they are used in HDD drives, electric motors, advanced medical instruments, as well as industrial machines.
  • Relatively small size with high pulling force – neodymium magnets offer impressive pulling force in small dimensions, which enables their usage in miniature devices

Cons

Disadvantages of NdFeB magnets:
  • Brittleness is one of their disadvantages. Upon intense impact they can break. We recommend keeping them in a strong case, which not only secures them against impacts but also raises their durability
  • Neodymium magnets lose force when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of power (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
  • Magnets exposed to a humid environment can corrode. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture
  • Due to limitations in creating threads and complicated shapes in magnets, we propose using a housing - magnetic holder.
  • Health risk to health – tiny shards of magnets are risky, if swallowed, which gains importance in the context of child safety. Additionally, small elements of these magnets are able to be problematic in diagnostics medical when they are in the body.
  • Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Pull force analysis

Maximum magnetic pulling forcewhat contributes to it?

Holding force of 14.00 kg is a measurement result executed under the following configuration:
  • using a base made of mild steel, serving as a magnetic yoke
  • possessing a massiveness of at least 10 mm to avoid saturation
  • characterized by lack of roughness
  • with total lack of distance (without paint)
  • during detachment in a direction perpendicular to the mounting surface
  • at temperature approx. 20 degrees Celsius

Impact of factors on magnetic holding capacity in practice

Please note that the application force may be lower depending on the following factors, starting with the most relevant:
  • Gap between surfaces – every millimeter of distance (caused e.g. by varnish or unevenness) diminishes the pulling force, often by half at just 0.5 mm.
  • Pull-off angle – remember that the magnet holds strongest perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the nominal value.
  • Substrate thickness – for full efficiency, the steel must be sufficiently thick. Paper-thin metal limits the attraction force (the magnet "punches through" it).
  • Material composition – different alloys attracts identically. High carbon content weaken the interaction with the magnet.
  • Surface condition – smooth surfaces ensure maximum contact, which increases force. Uneven metal reduce efficiency.
  • Thermal environment – temperature increase causes a temporary drop of force. Check the thermal limit for a given model.

Lifting capacity was measured by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as 5 times. Additionally, even a minimal clearance between the magnet’s surface and the plate decreases the lifting capacity.

Precautions when working with NdFeB magnets
Mechanical processing

Mechanical processing of NdFeB material poses a fire hazard. Neodymium dust reacts violently with oxygen and is hard to extinguish.

Impact on smartphones

Navigation devices and mobile phones are extremely sensitive to magnetism. Direct contact with a strong magnet can decalibrate the sensors in your phone.

Immense force

Handle magnets with awareness. Their powerful strength can shock even professionals. Be vigilant and respect their power.

Heat warning

Control the heat. Heating the magnet above 80 degrees Celsius will destroy its magnetic structure and strength.

Threat to electronics

Very strong magnetic fields can corrupt files on credit cards, hard drives, and storage devices. Stay away of min. 10 cm.

Health Danger

Life threat: Neodymium magnets can turn off heart devices and defibrillators. Stay away if you have medical devices.

Finger safety

Watch your fingers. Two powerful magnets will join instantly with a force of massive weight, crushing anything in their path. Be careful!

Warning for allergy sufferers

Nickel alert: The nickel-copper-nickel coating consists of nickel. If an allergic reaction happens, cease working with magnets and wear gloves.

Keep away from children

Only for adults. Tiny parts pose a choking risk, causing severe trauma. Keep away from kids and pets.

Eye protection

Protect your eyes. Magnets can fracture upon uncontrolled impact, ejecting sharp fragments into the air. Wear goggles.

Danger! Want to know more? Read our article: Are neodymium magnets dangerous?
Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98