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SM 25x250 [2xM8] / N42 - magnetic separator

magnetic separator

Catalog no 130293

GTIN/EAN: 5906301812869

5.00
Diameter Ø
25 mm [±1 mm]
Height
250 mm [±1 mm]
Weight
960 g
Magnetic Flux
~ 6 500 Gauss [±5%]

How we measure these parameters — certificates and measurements

check technical specifications »

560.00 zł net / pcs

688.80 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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Technical details - SM 25x250 [2xM8] / N42 - magnetic separator

Specification / characteristics - SM 25x250 [2xM8] / N42 - magnetic separator

properties
properties values
Cat. no. 130293
GTIN/EAN 5906301812869
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 250 mm [±1 mm]
Weight 960 g
Material Type Stainless steel AISI 304 / A2
Magnetic Flux ~ 6 500 Gauss [±5%]
Size/Mount Quantity 2xM8
Polarity circumferential - 9 poles
Casing Tube Thickness 1 mm
Manufacturing Tolerance ±1 mm

Magnetic properties of material N42

Specification / characteristics SM 25x250 [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 25x250 [2xM8] / N42

Parameter Value Description / Unit
Diameter (Ø) 25 mm
Total length 250 mm (L)
Active length 214 mm
Section count 9 modules
Dead zone 36 mm (2x 18mm starter)
Weight (est.) ~933 g
Active area 168 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 (9 sections)

Simulation: 9 magnetic modules (pitch 23 mm).

Chart 3: Temperature performance

Technical specification and ecology

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%

Ecology and recycling (GPSR)

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: 130293-2026
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A magnetic rod is the basic element of building grate separators and magnetic filters. It is mounted in chutes, hoppers, and pipelines to protect production machines from failure. High magnetic induction on the surface allows catching the finest iron particles.
The construction relies on a sealed, welded stainless steel housing, polished smooth. The core is a precise magnetic system generating high induction (Gauss). Such construction ensures full resistance to corrosion, water, oils, and acids.
Due to the high power of the magnet, direct removal of filings can be troublesome and time-consuming. The most effective home method is using adhesive tape, which we wrap around the dirt and peel off. 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. The economical version (8kGs) handles large pieces of metal perfectly. 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). You can choose a mounting method consistent with your technical design. Contact us for a quote on a non-standard dimension.

Strengths as well as weaknesses of rare earth magnets.

Pros

Besides their remarkable magnetic power, neodymium magnets offer the following advantages:
  • They have stable power, and over nearly ten years their performance decreases symbolically – ~1% (according to theory),
  • Magnets effectively resist against loss of magnetization caused by external fields,
  • A magnet with a smooth silver surface looks better,
  • Magnetic induction on the top side of the magnet turns out to be exceptional,
  • Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
  • Possibility of custom machining as well as adjusting to individual requirements,
  • Wide application in modern technologies – they find application in HDD drives, electric motors, medical devices, also multitasking production systems.
  • Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Limitations

Disadvantages of neodymium magnets:
  • At very strong impacts they can break, therefore we recommend placing them in special holders. A metal housing provides additional protection against damage, as well as increases the magnet's durability.
  • Neodymium magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of power (a factor is the shape as well as dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are very resistant to heat
  • Due to the susceptibility of magnets to corrosion in a humid environment, we advise using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
  • We recommend a housing - magnetic mount, due to difficulties in creating nuts inside the magnet and complicated forms.
  • Potential hazard resulting from small fragments of magnets are risky, when accidentally swallowed, which becomes key in the context of child health protection. Additionally, tiny parts of these magnets can complicate diagnosis medical after entering the body.
  • High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Pull force analysis

Maximum magnetic pulling force – what affects it?

The lifting capacity listed is a theoretical maximum value performed under the following configuration:
  • using a plate made of low-carbon steel, serving as a magnetic yoke
  • with a cross-section minimum 10 mm
  • with a surface free of scratches
  • with direct contact (no coatings)
  • under vertical force vector (90-degree angle)
  • at room temperature

Key elements affecting lifting force

It is worth knowing that the magnet holding may be lower depending on elements below, starting with the most relevant:
  • Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
  • Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet exhibits significantly lower power (typically approx. 20-30% of nominal force).
  • Metal thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of converting into lifting capacity.
  • Metal type – not every steel attracts identically. High carbon content weaken the attraction effect.
  • Surface quality – the more even the surface, the better the adhesion and higher the lifting capacity. Roughness acts like micro-gaps.
  • Thermal conditions – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, 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, whereas under shearing force the load capacity is reduced by as much as 75%. In addition, even a slight gap between the magnet’s surface and the plate decreases the load capacity.

Warnings
Pinching danger

Pinching hazard: The pulling power is so immense that it can cause blood blisters, pinching, and broken bones. Use thick gloves.

Skin irritation risks

Medical facts indicate that nickel (the usual finish) is a potent allergen. If you have an allergy, prevent direct skin contact or select versions in plastic housing.

Mechanical processing

Fire hazard: Neodymium dust is explosive. Do not process magnets without safety gear as this may cause fire.

Conscious usage

Before starting, check safety instructions. Sudden snapping can break the magnet or injure your hand. Think ahead.

Do not overheat magnets

Do not overheat. NdFeB magnets are sensitive to temperature. If you need operation above 80°C, inquire about special high-temperature series (H, SH, UH).

No play value

Adult use only. Small elements can be swallowed, causing severe trauma. Keep out of reach of children and animals.

Life threat

For implant holders: Strong magnetic fields affect medical devices. Keep minimum 30 cm distance or request help to handle the magnets.

Magnetic media

Device Safety: Strong magnets can ruin data carriers and sensitive devices (pacemakers, medical aids, mechanical watches).

Fragile material

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

Magnetic interference

A strong magnetic field negatively affects the operation of magnetometers in phones and navigation systems. Maintain magnets near a smartphone to prevent damaging the sensors.

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