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SM 25x375 [2xM8] / N42 - magnetic separator

magnetic separator

Catalog no 130351

GTIN/EAN: 5906301812999

Diameter Ø
25 mm [±1 mm]
Height
375 mm [±1 mm]
Weight
1460 g
Magnetic Flux
~ 6 500 Gauss [±5%]

How we measure these parameters — certificates and measurements

view technical data »

860.00 zł net / pcs

1057.80 zł with VAT (23% VAT) / pcs

price for transport

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Frequently asked questions

Which rod should I choose for fine contamination?
For particles below 0.5 mm — a Ø32 mm rod in grade N52, with surface induction of about 10,000 Gs. A Ø25 rod in grade N42 gives about 6,500 Gs and is chosen for contamination above 1 mm: bolts, washers, pieces of wire.
Which rod pitch should I choose?
The narrow pitch, 40 mm centre to centre, for fine free-flowing fractions — it gives denser coverage of the cross-section. The wide pitch, 50 mm, for granulates and for damp, greasy or sticky materials, where a narrow pitch risks the material bridging above the rods.
Why does efficiency drop after a few weeks of operation?
Almost always because the separator has not been cleaned. The layer of captured particles shields the field, and further particles settle on that layer rather than on the rod surface, where the gradient is far stronger. The magnets themselves do not weaken at that rate.

Guides from the knowledge base

Want to talk magnets?

Call us now +48 888 99 98 98 alternatively let us know using contact form the contact section.
Specifications and structure of a neodymium magnet can be estimated using our power calculator.

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Detailed specification - SM 25x375 [2xM8] / N42 - magnetic separator

Specification / characteristics - SM 25x375 [2xM8] / N42 - magnetic separator

properties
properties values
Cat. no. 130351
GTIN/EAN 5906301812999
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 Ø 25 mm [±1 mm]
Height 375 mm [±1 mm]
Weight 1460 g
Material Type Stainless steel AISI 304 / A2
Magnetic Flux ~ 6 500 Gauss [±5%]
Size/Mount Quantity 2xM8
Polarity circumferential - 14 poles
Casing Tube Thickness 1 mm
Manufacturing Tolerance ±1 mm

Magnetic properties of material N42

Specification / characteristics SM 25x375 [2xM8] / N42 - magnetic separator
properties values units
remenance Br [min. - max.] ? 12.9-13.2 kGs
remenance Br [min. - max.] ? 1290-1320 mT
coercivity bHc ? 10.8-12.0 kOe
coercivity bHc ? 860-955 kA/m
actual internal force iHc ≥ 12 kOe
actual internal force iHc ≥ 955 kA/m
energy density [min. - max.] ? 40-42 BH max MGOe
energy density [min. - max.] ? 318-334 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 310 °C
Curie Temperature TF 590 °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

Table 1: Rod construction
SM 25x375 [2xM8] / N42

Parameter Value Description / Unit
Diameter (Ø) 25 mm
Total length 375 mm (L)
Active length 339 mm
Section count 14 modules
Dead zone 36 mm (2x 18mm starter)
Weight (est.) ~1399 g
Active area 266 cm² (Area)
Housing material AISI 304 1.4301 (Inox)
Surface finish Ra < 0.8 µm Polished
Temp. class 80°C Standard (N)
Force loss (at max °C) -12.8% Reversible loss (physics)
Force (calculated) 10.6 kg (theor.)
Induction (surface) ~6 500 Gauss (Max)
Max T = 80°C. Construction data for M8/M10 thread series.

Chart 2: Field profile (14 sections)

Simulation: 14 magnetic modules (pitch 23 mm).

Chart 3: Temperature performance

Technical and environmental data

Chemical composition

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: 130351-2026
Measurement Calculator

Magnet pull force

Magnetic Induction

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It is the "heart" of every magnetic filter used in industry for cleaning raw materials. It is commonly used for cleaning flour, sugar, plastic granules, as well as oils and coolants. Thanks to the use of strong neodymium magnets, the rod catches even metallic dust.
The construction relies on a sealed, welded stainless steel housing, polished smooth. Inside there is a stack of strong neodymium magnets arranged in a special configuration (magnetic circuit). Such construction ensures full resistance to corrosion, water, oils, and acids.
Metal contaminants are strongly attracted, so removing them with a bare hand or glove can be difficult. The most effective home method is using adhesive tape, which we wrap around the dirt and peel off. For easier operation, it is worth considering ordering a rod in a version with a cleaning sleeve.
The more Gauss, the smaller and more weakly magnetic particles will be effectively caught. For basic machine protection against pieces of iron, standard power is sufficient. High induction is necessary when contaminants are microscopic or weakly magnetic.
Yes, as a manufacturer, we make rods of any length and diameter (standard is dia 25mm and 32mm). The rod end is strictly adapted to the fastening system in your device. We ensure fast realization of special orders and technical advice.

Strengths and weaknesses of rare earth magnets.

Strengths

Besides their durability, neodymium magnets are valued for these benefits:
  • Their power remains stable, and after approximately ten years it drops only by ~1% (according to research),
  • They feature excellent resistance to magnetic field loss due to opposing magnetic fields,
  • A magnet with a metallic nickel surface has better aesthetics,
  • The surface of neodymium magnets generates a maximum magnetic field – this is a key feature,
  • Thanks to resistance to high temperature, they can operate (depending on the shape) even at temperatures up to 230°C and higher...
  • Thanks to versatility in shaping and the ability to customize to individual projects,
  • Wide application in high-tech industry – they are commonly used in data components, brushless drives, medical equipment, and modern systems.
  • Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages

Drawbacks and weaknesses of neodymium magnets and proposals for their use:
  • Brittleness is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a strong case, which not only protects them against impacts but also increases their durability
  • When exposed to high temperature, neodymium magnets suffer a drop in strength. Often, when the temperature exceeds 80°C, their power decreases (depending on the size and shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
  • Magnets exposed to a humid environment can rust. Therefore when using outdoors, we recommend using waterproof magnets made of rubber, plastic or other material protecting against moisture
  • We recommend cover - magnetic mount, due to difficulties in creating nuts inside the magnet and complicated forms.
  • Health risk related to microscopic parts of magnets can be dangerous, if swallowed, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these magnets can disrupt the diagnostic process medical in case of swallowing.
  • With budget limitations the cost of neodymium magnets can be a barrier,

Pull force analysis

Maximum lifting force for a neodymium magnet – what affects it?

Magnet power was defined for ideal contact conditions, taking into account:
  • on a base made of structural steel, optimally conducting the magnetic flux
  • whose thickness equals approx. 10 mm
  • with an ideally smooth touching surface
  • without any insulating layer between the magnet and steel
  • for force acting at a right angle (pull-off, not shear)
  • at ambient temperature approx. 20 degrees Celsius

Determinants of lifting force in real conditions

During everyday use, the actual lifting capacity is determined by many variables, listed from most significant:
  • Space between surfaces – every millimeter of separation (caused e.g. by veneer or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
  • Loading method – declared lifting capacity refers to pulling vertically. When applying parallel force, the magnet exhibits much less (typically approx. 20-30% of maximum force).
  • Base massiveness – insufficiently thick steel does not close the flux, causing part of the flux to be wasted into the air.
  • Plate material – mild steel attracts best. Alloy steels reduce magnetic properties and lifting capacity.
  • Smoothness – full contact is possible only on smooth steel. Any scratches and bumps create air cushions, weakening the magnet.
  • Operating temperature – NdFeB sinters have a sensitivity to temperature. When it is hot they are weaker, and in frost they can be stronger (up to a certain limit).

Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under shearing force the load capacity is reduced by as much as 5 times. In addition, even a minimal clearance between the magnet’s surface and the plate decreases the load capacity.

Safe handling of NdFeB magnets
GPS and phone interference

GPS units and smartphones are highly sensitive to magnetic fields. Direct contact with a strong magnet can ruin the internal compass in your phone.

Keep away from computers

Do not bring magnets close to a wallet, computer, or TV. The magnetic field can permanently damage these devices and wipe information from cards.

Demagnetization risk

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

Swallowing risk

Only for adults. Small elements can be swallowed, leading to severe trauma. Store out of reach of kids and pets.

Sensitization to coating

Certain individuals have a contact allergy to nickel, which is the standard coating for neodymium magnets. Extended handling can result in skin redness. It is best to use safety gloves.

Crushing force

Large magnets can smash fingers instantly. Do not put your hand between two strong magnets.

Dust is flammable

Powder produced during grinding of magnets is flammable. Do not drill into magnets without proper cooling and knowledge.

Safe operation

Use magnets with awareness. Their powerful strength can surprise even experienced users. Be vigilant and do not underestimate their power.

Implant safety

For implant holders: Powerful magnets affect medical devices. Maintain minimum 30 cm distance or request help to handle the magnets.

Beware of splinters

Protect your eyes. Magnets can explode upon violent connection, ejecting sharp fragments into the air. Wear goggles.

Attention! Looking for details? Read our article: Are neodymium magnets dangerous?