e-mail: bok@dhit.pl

neodymium magnets

We offer blue color magnets Nd2Fe14B - our store's offer. All magnesy neodymowe in our store are in stock for immediate purchase (see the list). Check out the magnet price list for more details see the magnet price list

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SM 25x400 [2xM8] / N42 - magnetic roller

magnetic separator

catalog number 130365

no reviews

diameter Ø

25 mm [±0,1 mm]


400 mm [±0,1 mm]

max. temperature

≤ 80 °C

1131.60 PLN gross price (including VAT) / pcs +

920.00 PLN net price + 23% VAT / pcs

bulk discounts:

need more quantity?

price from 1 pcs
920.00 PLN
1131.60 PLN
price from 3 pcs
874.00 PLN
1075.02 PLN
price from 5 pcs
828.00 PLN
1018.44 PLN

Want a better price?

Call us tel: +48 888 99 98 98 or get in touch via contact form on the contact page. You can check the mass and the shape of neodymium magnet in our force calculator force calculator

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

Specification: magnetic separator 25x400 [2xM8] / N42

Characteristics: magnetic separator 25x400 [2xM8] / N42
catalog number
production / distribution
Dhit sp. z o.o.
country of origin
Poland / China / Germany
customs code
diameter Ø
25 mm [±0,1 mm]
400 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 N42
ilość gwintów
2x [M8] wewnętrzne
obwodowa - 15 nabiegunników
indukcja magnetyczna
~ 6 500 Gauss [±5%]
max. temp. pracy
poniżej ≤ 80°C
grubość rury osłonowej
1 mm

Magnetic properties of the material N42

material characteristics N42
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 device rod magnetic is based on the use of neodymium magnets, which are embedded in a casing made of stainless steel usually AISI304. In this way, it is possible to precisely separate ferromagnetic particles from the mixture. A fundamental component of its operation is the repulsion of magnetic poles N and S, which allows magnetic substances to be collected. The thickness of the magnet and its structure's pitch affect the range and strength of the separator's operation.
Generally speaking, magnetic separators are designed to extract ferromagnetic elements. If the cans are ferromagnetic, the separator will be able to separate 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 to clear metallic contaminants, including iron fragments or iron dust. Our rollers are constructed from durable acid-resistant steel, AISI 304, suitable for use in food.
Magnetic rollers, otherwise magnetic separators, are employed in food production, metal separation as well as recycling. They help in extracting iron dust during the process of separating metals from other materials.
Our magnetic rollers are composed of neodymium magnets placed in a stainless steel tube cylinder of stainless steel with a wall thickness of 1mm.
Both ends of the magnetic bar can be with M8 threaded holes - 18 mm, enabling easy installation in machines or magnetic filter drawers. A "blind" version is also possible in manual separators.
In terms of features, magnetic bars differ in terms of magnetic force lines, flux density and the area of operation of the magnetic field. We produce them in two materials, N42 as well as N52.
Often it is believed that the stronger the magnet, the better. Nevertheless, 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 use and specific needs. The standard operating temperature of a magnetic bar is 80°C.
In the case where the magnet is thin, the magnetic force lines will be short. By contrast, in the case of a thicker magnet, the force lines are extended and reach further.
For creating the casings of magnetic separators - rollers, usually stainless steel is utilized, especially types AISI 304, AISI 316, and AISI 316L.
In a salt water environment, AISI 316 steel is recommended due to its exceptional corrosion resistance.
Magnetic rollers stand out for their unique configuration of poles and their ability to attract magnetic particles directly onto their surface, in contrast to other devices that often use more complicated filtration systems.
Technical designations and terms related to magnetic separators include among others magnet pitch, polarity, and magnetic induction, as well as the type of steel used.
Magnetic induction for a roller is measured using a teslameter or a gaussmeter with a flat Hall-effect probe, seeking the highest magnetic field value near the magnetic pole. The outcome is verified in a value table - the lowest is N30. All designations below N27 or N25 suggest recycling that doesn't meet the standard - they are not suitable.
Neodymium magnetic rollers 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.
To properly maintain of neodymium magnetic rollers, it is suggested {to clean them regularly from deposits, avoid extremal temperatures above 80 degrees, and protect them from moisture if the threads are not sealed - in our case. The rollers have an IP67 waterproof rating, so if they are not watertight, the magnets inside may oxidize and weaken. Magnetic field measurements are suggested to be conducted once every 24 months. Care should be taken as there is a possibility of finger injury. If the protective tube is only 0.5 mm thick, it can wear out, which, in turn, can result in issues with the magnetic rod becoming unsealed and product contamination. The effective operating range of the roller equals its diameter, fi25mm is approximately 25mm active range, while fi32 is about 40mm.

Compilation of suggested goods

Advantages as well as disadvantages of neodymium magnets NdFeB.

Apart from immense power, neodymium magnets have the following advantages:

  • They do not lose power over time - after about 10 years, their strength decreases by only ~1% (theoretically),
  • They are extremely resistant to demagnetization by external magnetic sources,
  • In other words, thanks to the glossy nickel, gold, or silver finish, the element gains an visually attractive appearance,
  • They exhibit very high magnetic induction on the surface of the magnet,
  • By using an appropriate combination of materials, they can achieve high 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 various forms and dimensions, which enhances their versatility in applications.
  • Significant importance in advanced technologically fields – are utilized in hard drives, electric motors, medical devices and very advanced devices.

Disadvantages of neodymium magnets:

  • They can break as they are extremely fragile when subjected to a strong impact. If the magnets are exposed to impacts, it is suggested using magnets in a protective case. The steel housing in the form of a holder protects the magnet from impacts and simultaneously increases its overall strength,
  • Magnets lose their power due to exposure to high temperatures. In most cases, when the temperature exceeds 80°C, these magnets experience permanent loss in strength (although it is worth noting that this is dependent on the shape and size of the magnet). To avoid this problem, we offer special magnets marked with the [AH] symbol, which exhibit high temperature resistance. They can operate even at temperatures as high as 230°C or more,
  • 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,
  • Limited ability to create threads or complex shapes in the magnet - the use of a housing is recommended - magnetic holder
  • Possible danger to health from tiny fragments of magnets are risky, in case of ingestion, which is crucial in the context of child safety. It's also worth noting that miniscule components of these devices have the potential to complicate diagnosis when they are in the body.

Handle Neodymium Magnets with Caution

Make sure not to bring neodymium magnets close to the TV, wallet, and computer HDD.

Neodymium magnets generate strong magnetic fields that can destroy magnetic media such as floppy disks, video tapes, HDDs, credit cards, magnetic ID cards, cassette tapes, etc. devices. They can also damage videos, televisions, CRT computer monitors. Do not forget to keep neodymium magnets away from these electronic devices.

Under no circumstances should neodymium magnets be brought close to GPS and smartphones.

Magnetic fields generated by neodymium magnets interfere with compasses and magnetometers used in navigation, as well as internal compasses of smartphones and GPS devices.

Neodymium magnetic are characterized by being fragile, which can cause them to become damaged.

Neodymium magnets are extremely delicate, and by joining them in an uncontrolled manner, they will crack. Neodymium magnets are made of metal and coated with a shiny nickel surface, but they are not as hard as steel. In the event of a collision between two magnets, there may be a scattering of fragments in different directions. Protecting your eyes is crucial in such a situation.

 It is essential to maintain neodymium magnets away from youngest children.

Neodymium magnets are not toys. You cannot allow them to become toys for children. In such a situation, surgery is necessary to remove them. In the worst case scenario, it can result in death.

It is crucial not to allow the magnets to pinch together uncontrollably or place your fingers in their path as they attract to each other.

Magnets will bounce and clash together within a radius of several to almost 10 cm from each other.

Dust and powder from neodymium magnets are flammable.

Do not attempt to drill into neodymium magnets. Mechanical processing is also not recommended. Once crushed into fine powder or dust, this material becomes highly flammable.

Neodymium magnets can become demagnetized at high temperatures.

Whilst Neodymium magnets can lose their magnetic properties at high temperatures, it's important to note that the extent of this effect can vary based on factors such as the magnet's material, shape, and intended application.

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

To use magnets properly, it is best to familiarize yourself with our information beforehand. This will help you avoid significant harm to your body and the magnets themselves.

People with pacemakers are advised to avoid neodymium magnets.

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.

The magnet coating contains nickel, so be cautious if you have a nickel allergy.

Studies clearly indicate a small percentage of people who suffer from metal allergies such as nickel. An allergic reaction often manifests as skin redness and rash. If you have a nickel allergy, try wearing gloves or avoid direct contact with nickel-plated neodymium magnets.

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

Dhit sp. z o.o. logo

e-mail: bok@dhit.pl

tel: +48 888 99 98 98