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neodymium magnets

We offer red color magnetic Nd2Fe14B - our offer. Practically all "magnets" on our website are in stock for immediate delivery (check the list). See the magnet pricing for more details see the magnet price list

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SM 25x250 [2xM8] / N52 - magnetic roller

magnetic separator

catalog number 130371


diameter Ø

25 mm [±0,1 mm]


250 mm [±0,1 mm]

max. temperature

≤ 80 °C

762.60 PLN gross price (including VAT) / pcs +

620.00 PLN net price + 23% VAT / pcs

bulk discounts:

need more quantity?

price from 1 pcs
620.00 PLN
762.60 PLN
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589.00 PLN
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price from 8 pcs
558.00 PLN
686.34 PLN

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Call us tel: +48 22 499 98 98 or contact us through contact form on our website. You can check the lifting capacity as well as the appearance of neodymium magnets in our force calculator power calculator

Orders placed by 2:00 PM will be shipped on the same business day.

Specification: magnetic separator 25x250 [2xM8] / N52

Characteristics: magnetic separator 25x250 [2xM8] / N52
catalog number
production / distribution
Dhit sp. z o.o.
country of origin
Poland / China / Germany
customs code
diameter Ø
25 mm [±0,1 mm]
250 mm [±0,1 mm]
max. temperature ?
≤ 80 °C
0.01 g
execution tolerance
± 0.1 mm
rodzaj materiału
AISI 304 - bezpieczna dla żywności
rodzaj magnesów
NdFeB N52
ilość gwintów
2x [M8] wewnętrzne
obwodowa - 9 nabiegunników
indukcja magnetyczna
~ 9 500 Gauss [±5%]
max. temp. pracy
poniżej ≤ 80°C
grubość rury osłonowej
1 mm

Magnetic properties of the material N52

material characteristics N52
remenance Br [Min. - Max.] ?
remenance Br [Min. - Max.] ?
coercivity bHc ?
coercivity bHc ?
actual internal force iHc
≥ 12
actual internal force iHc
≥ 955
energy density [Min. - Max.]
BH max MGOe
energy density [Min. - Max.]
BH max KJ/m
max. temperature
≤ 80

Physical properties of sintered neodymium magnets Nd2Fe14B

Physical properties of sintered neodymium magnets Nd2Fe14B
Vickers hardness
Curie Temperature TC
312 - 380
Curie Temperature TF
593 - 716
Specific resistance
Bending strength
Compressive strength
Thermal expansion parallel (∥) to orientation (M)
(3-4) x 106
Thermal expansion perpendicular (⊥) to orientation (M)
-(1-3) x 10-6
Young's modulus
1.7 x 104
The magnetic separator, namely the magnetic roller, uses the power of neodymium magnets, placed in a construction made of stainless steel usually AISI304. Due to this, it is possible to efficiently separate ferromagnetic particles from other materials. A fundamental component of its operation is the repulsion of N and S poles of neodymium magnets, which enables magnetic substances to be attracted. The thickness of the magnet and its structure's pitch affect the range and strength of the separator's operation.
Generally speaking, magnetic separators serve to separate ferromagnetic elements. If the cans are made from ferromagnetic materials, the separator will effectively segregate them. However, if the cans are made of non-ferromagnetic materials, such as aluminum, the magnetic separator will not be effective.
Yes, magnetic rollers find application in the food industry for the elimination of metallic contaminants, for example iron fragments or iron dust. Our rods are constructed from durable acid-resistant steel, EN 1.4301, approved for contact with food.
Magnetic rollers, often called cylindrical magnets, are used in food production, metal separation as well as waste processing. They help in eliminating iron dust during the process of separating metals from other materials.
Our magnetic rollers are composed of neodymium magnets anchored in a stainless steel tube cylinder made of stainless steel with a wall thickness of 1mm.
Both ends of the magnetic bar will be with M8 threaded holes - 18 mm, enabling quick installation in machines or magnetic filter drawers. A "blind" version is also possible in manual separators.
In terms of forces, magnetic bars stand out in terms of magnetic force lines, flux density and the area of operation of the magnetic field. We produce them in two materials, N42 and N52.
Generally it is believed that the stronger the magnet, the more efficient it is. But, the effectiveness of the magnet's power depends on the height of the used magnet and the quality of the material [N42] or [N52], as well as on the area of application and expected needs. The standard operating temperature of a magnetic bar is 80°C.
If the magnet is thin, the magnetic force lines are short. By contrast, in the case of a thicker magnet, the force lines are longer and reach further.
For constructing the casings of magnetic separators - rollers, most often stainless steel is utilized, particularly types AISI 316, AISI 316L, and AISI 304.
In a salt water contact, AISI 316 steel exhibits the best resistance thanks to its outstanding anti-corrosion properties.
Magnetic bars are characterized by their unique configuration of poles and their capability to attract magnetic particles directly onto their surface, as opposed to other separators that often use more complicated filtration systems.
Technical designations and terms pertaining to magnetic separators comprise amongst others magnet pitch, polarity, and magnetic induction, as well as the steel type applied.
Magnetic induction for a magnet on a roller is measured using a teslameter or a gaussmeter with a flat Hall-effect probe, aiming to find the highest magnetic field value near the magnetic pole. The result is verified in a value table - the lowest is N30. All designations below N27 or N25 indicate recycling that doesn't meet the standard - they are not suitable.
Neodymium magnetic bars offer many advantages, including a very strong magnetic field, the ability to capture even the tiniest metal particles, and durability. Disadvantages may include the need for regular cleaning, higher cost, and potential installation challenges.
For proper maintenance of neodymium magnetic rollers, it is advised {to clean them regularly from contaminants, avoid extreme temperatures up to 80°C, and to clean them regularly, avoiding temperatures above 80 degrees. The rollers have an IP67 waterproof rating, so if they are not sealed, the magnets inside may oxidize and lose their strength. Roller inspections are advised to be conducted once every 24 months. Caution should be exercised during use as there is a risk of finger injury. If the protective tube is only 0.5 mm thick, it can be worn down, which, in turn, may lead to issues with the magnetic rod becoming unsealed and product contamination. The Roller operating range equals its diameter, fi25mm is approximately 25mm active range, while fi32 is about 40mm.

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Advantages as well as disadvantages of neodymium magnets NdFeB.

In addition to immense power, neodymium magnets have the following advantages:

  • They do not lose their strength (of the magnet). After approximately 10 years, their power decreases by only ~1% (theoretically),
  • They protect against demagnetization caused by external magnetic sources very well,
  • Thanks to the shiny finish and nickel, gold, or silver coating, they have an aesthetic appearance,
  • They exhibit extremely high magnetic induction on the surface of the magnet,
  • By using an appropriate combination of materials, they can achieve significant thermal resistance, allowing them to operate at temperatures up to 230°C and above...
  • Due to the option of accurate forming and adaptation to individual needs – neodymium magnets can be produced in a wide range of shapes and sizes, which enhances their versatility in applications.
  • Significant importance in advanced technologically fields – find application in hard drives, electric drive mechanisms, medical equipment and other highly developed apparatuses.

Disadvantages of neodymium magnets:

  • They can break as they are fragile when subjected to a powerful impact. If the magnets are exposed to impacts, it is suggested using magnets in a steel housing. The steel housing in the form of a holder protects the magnet from impacts and also increases its overall strength,
  • High temperatures can reduce the power of neodymium magnets. Typically, after heating above 80°C, most of them experience a permanent loss in strength (although it is dependent on the shape and size). To prevent this, we offer special magnets marked with the symbol [AH], which are highly resistant to high temperatures. They can operate even at temperatures up to 230°C, making them an ideal solution for applications requiring high-temperature operation,
  • Due to their susceptibility to corrosion in a humid environment, we suggest using waterproof magnets made of rubber, plastic, or other moisture-resistant materials when using them outdoors,
  • The use of a cover or a magnetic holder is recommended due to the limited possibilities of manufacturing threads or complex shapes in the magnet
  • Health risk to health from tiny fragments of magnets are risky, if swallowed, which is particularly important in the context of child safety. It's also worth noting that tiny parts of these products can complicate diagnosis after entering the body.

Exercise Caution with Neodymium Magnets

 Maintain neodymium magnets far from children.

Remember that neodymium magnets are not toys. Do not allow children to play with them. They can be a significant choking hazard. If multiple magnets are swallowed, they can attract to each other through the intestinal walls, causing significant injuries, and even death.

Do not place neodymium magnets near a computer HDD, TV, and wallet.

Magnetic fields generated by neodymium magnets can damage magnetic storage media such as floppy disks, credit cards, magnetic ID cards, cassette tapes, video tapes, or other similar devices. They can also damage televisions, VCRs, computer monitors, and CRT displays. Avoid placing neodymium magnets in close proximity to electronic devices.

Neodymium magnets are over 10 times more powerful than ferrite magnets (the ones in speakers), and their strength can surprise you.

On our website, you can find information on how to use neodymium magnets. This will help you avoid injuries and prevent damage to the magnets.

Magnets will attract to each other, so remember not to allow them to pinch together without control or place your fingers in their path.

If the joining of neodymium magnets is not under control, at that time they may crumble and also crack. Remember not to approach them to each other or have them firmly in hands at a distance less than 10 cm.

The magnet is coated with nickel. Therefore, exercise caution if you have an allergy.

Studies show a small percentage of people have allergies to certain metals, including nickel. An allergic reaction often manifests as skin redness and rash. If you have a nickel allergy, you can try wearing gloves or simply avoid direct contact with nickel-plated neodymium magnets.

Keep neodymium magnets away from people with pacemakers.

In the case of neodymium magnets, there is a strong magnetic field. As a result, it interferes with the operation of a heart pacemaker. Even if the magnetic field does not affect the device, it can damage its components or deactivate the entire device.

Keep neodymium magnets as far away as possible from GPS and smartphones.

Magnetic fields interfere with compasses and magnetometers used in navigation for air and sea transport, as well as internal compasses of smartphones and GPS devices.

Neodymium magnets are fragile as well as can easily break as well as get damaged.

Neodymium magnetic are fragile as well as will shatter if allowed to collide with each other, even from a distance of a few centimeters. They are coated with a shiny nickel plating similar to steel, but they are not as hard. In the case of a collision between two magnets, there can be a scattering of small sharp metal fragments in different directions. Protecting your eyes is essential.

Neodymium magnets can demagnetize at high temperatures.

Despite the fact that magnets have been observed to maintain their efficacy up to temperatures of 80°C or 175°F, it's essential to consider that this threshold may fluctuate depending on the magnet's type, configuration, and intended usage.

Dust and powder from neodymium magnets are flammable.

Avoid drilling or mechanical processing of neodymium magnets. Once crushed into fine powder or dust, this material becomes highly flammable.

So you are aware of why neodymium magnets are so dangerous, see the article titled How dangerous are strong neodymium magnets?.

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