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SM 25x125 [2xM8] / N42 - magnetic separator

magnetic separator

Catalog no 130288

GTIN/EAN: 5906301812814

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

How we measure these parameters — certificates and measurements

see specifications »

320.00 zł net / pcs

393.60 zł with VAT (23% VAT) / pcs

price for transport

bulk discounts:

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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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Product card - SM 25x125 [2xM8] / N42 - magnetic separator

Specification / characteristics - SM 25x125 [2xM8] / N42 - magnetic separator

properties
properties values
Cat. no. 130288
GTIN/EAN 5906301812814
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 125 mm [±1 mm]
Weight 460 g
Material Type Stainless steel AISI 304 / A2
Magnetic Flux ~ 6 500 Gauss [±5%]
Size/Mount Quantity 2xM8
Polarity circumferential - 4 poles
Casing Tube Thickness 1 mm
Manufacturing Tolerance ±1 mm

Magnetic properties of material N42

Specification / characteristics SM 25x125 [2xM8] / N42 - magnetic separator
properties values units
Remanence Br ? 12.9-13.2 kGs
Remanence Br ? 1290-1320 mT
Coercivity bHc ? 10.8-12.0 kOe
Coercivity bHc ? 860-955 kA/m
Intrinsic coercivity iHc ≥ 12 kOe
Intrinsic coercivity iHc ≥ 955 kA/m
Energy product BHmax ? 40-42 BH max MGOe
Energy product BHmax ? 318-334 BH max KJ/m
Maximum working 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 25x125 [2xM8] / N42

Parameter Value Description / Unit
Diameter (Ø) 25 mm
Total length 125 mm (L)
Active length 89 mm
Section count 3 modules
Dead zone 36 mm (2x 18mm starter)
Weight (est.) ~466 g
Active area 70 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 (3 sections)

Simulation: 3 magnetic modules (pitch 23 mm).

Chart 3: Temperature performance

Technical and environmental data

Material specification

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: 130288-2026
Measurement Calculator

Force (pull)

Magnetic Field

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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. The center is filled with NdFeB magnets and pole pieces, arranged to maximize the field on the tube surface. Such construction ensures full resistance to corrosion, water, oils, and acids.
Metal filings stick to the surface very strongly, so cleaning requires strength or cleverness. We recommend sticking packing tape to the cluster of filings and tearing it off together with the contaminants. In industry, cover tubes (so-called Easy Clean system) are used, from which the magnetic insert slides out.
The more Gauss, the smaller and more weakly magnetic particles will be effectively caught. Standard rods (~8000 Gs) are sufficient for catching screws, nails, and steel shavings. For the food and precision industry, we recommend the highest induction parameters.
Yes, as a manufacturer, we make rods of any length and diameter (standard is dia 25mm and 32mm). You can choose a mounting method consistent with your technical design. We ensure fast realization of special orders and technical advice.

Advantages and disadvantages of Nd2Fe14B magnets.

Strengths

Apart from their strong holding force, neodymium magnets have these key benefits:
  • They have stable power, and over more than ten years their attraction force decreases symbolically – ~1% (according to theory),
  • They are noted for resistance to demagnetization induced by external field influence,
  • By covering with a shiny layer of gold, the element gains an proper look,
  • They feature high magnetic induction at the operating surface, which increases their power,
  • Neodymium magnets are characterized by very high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
  • In view of the option of flexible shaping and customization to individualized projects, neodymium magnets can be modeled in a broad palette of forms and dimensions, which makes them more universal,
  • Universal use in future technologies – they find application in computer drives, electric motors, diagnostic systems, also other advanced devices.
  • Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Weaknesses

Disadvantages of neodymium magnets:
  • They are fragile upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also increases its resistance to damage
  • Neodymium magnets decrease their force under the influence of heating. As soon as 80°C is exceeded, many of them start losing their force. Therefore, we recommend our special magnets marked [AH], which maintain stability even at temperatures up to 230°C
  • They oxidize in a humid environment - during use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
  • We recommend casing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated forms.
  • Potential hazard to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the context of child safety. It is also worth noting that small components of these products are able to be problematic in diagnostics medical in case of swallowing.
  • High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which hinders application in large quantities

Lifting parameters

Highest magnetic holding force – what contributes to it?

The force parameter is a result of laboratory testing performed under specific, ideal conditions:
  • with the contact of a yoke made of low-carbon steel, ensuring full magnetic saturation
  • whose transverse dimension is min. 10 mm
  • characterized by smoothness
  • without any clearance between the magnet and steel
  • for force acting at a right angle (pull-off, not shear)
  • at standard ambient temperature

What influences lifting capacity in practice

It is worth knowing that the working load will differ subject to the following factors, starting with the most relevant:
  • Distance – existence of any layer (paint, dirt, gap) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
  • Direction of force – highest force is obtained only during pulling at a 90° angle. The force required to slide of the magnet along the plate is usually many times smaller (approx. 1/5 of the lifting capacity).
  • Plate thickness – insufficiently thick steel does not close the flux, causing part of the flux to be escaped into the air.
  • Steel grade – the best choice is high-permeability steel. Stainless steels may have worse magnetic properties.
  • Surface quality – the smoother and more polished the plate, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
  • Temperature influence – high temperature reduces pulling force. Too high temperature can permanently damage the magnet.

Lifting capacity was measured by applying a polished steel plate of suitable thickness (min. 20 mm), under perpendicular detachment force, whereas under shearing force the holding force is lower. In addition, even a small distance between the magnet’s surface and the plate reduces the holding force.

Safety rules for work with neodymium magnets
Data carriers

Equipment safety: Neodymium magnets can ruin data carriers and delicate electronics (heart implants, hearing aids, mechanical watches).

Allergic reactions

Some people experience a hypersensitivity to nickel, which is the typical protective layer for NdFeB magnets. Extended handling can result in a rash. We strongly advise use protective gloves.

Life threat

Patients with a pacemaker have to maintain an safe separation from magnets. The magnetic field can stop the operation of the life-saving device.

Material brittleness

NdFeB magnets are sintered ceramics, meaning they are prone to chipping. Impact of two magnets leads to them shattering into small pieces.

Danger to the youngest

Absolutely store magnets away from children. Choking hazard is significant, and the effects of magnets clamping inside the body are very dangerous.

Do not drill into magnets

Machining of neodymium magnets poses a fire risk. Neodymium dust reacts violently with oxygen and is difficult to extinguish.

Handling rules

Handle with care. Neodymium magnets attract from a distance and connect with huge force, often quicker than you can react.

Finger safety

Large magnets can break fingers instantly. Do not put your hand between two attracting surfaces.

Permanent damage

Avoid heat. Neodymium magnets are sensitive to temperature. If you require resistance above 80°C, ask us about HT versions (H, SH, UH).

Threat to navigation

Note: rare earth magnets generate a field that confuses precision electronics. Keep a safe distance from your mobile, device, and navigation systems.

Attention! More info about hazards in the article: Safety of working with magnets.