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neodymium magnets

We offer yellow color magnetic Nd2Fe14B - our offer. All "magnets" in our store are available for immediate delivery (check the list). Check out the magnet pricing for more details check the magnet price list

Magnet for water searching F300 GOLD

Where to purchase strong neodymium magnet? Magnet holders in airtight, solid enclosure are ideally suited for use in variable and difficult weather, including snow and rain more...

magnets with holders

Magnetic holders can be applied to facilitate production processes, underwater exploration, or searching for meteors from gold more information...

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MP 12x8/4x3 / N38 - ring magnet

ring magnet

Catalog no 030395

GTIN: 5906301812326

5

Diameter [±0,1 mm]

12 mm

internal diameter Ø [±0,1 mm]

8/4 mm

Height [±0,1 mm]

3 mm

Weight

4.24 g

Magnetization Direction

↑ axial

Load capacity

0.68 kg / 6.67 N

Magnetic Induction

237.19 mT

Coating

[NiCuNi] nickel

1.427 with VAT / pcs + price for transport

1.160 ZŁ net + 23% VAT / pcs

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MP 12x8/4x3 / N38 - ring magnet
Specification/characteristics MP 12x8/4x3 / N38 - ring magnet
properties
values
Cat. no.
030395
GTIN
5906301812326
Production/Distribution
Dhit sp. z o.o.
Country of origin
Poland / China / Germany
Customs code
85059029
Diameter
12 mm [±0,1 mm]
internal diameter Ø
8/4 mm [±0,1 mm]
Height
3 mm [±0,1 mm]
Weight
4.24 g [±0,1 mm]
Magnetization Direction
↑ axial
Load capacity ~ ?
0.68 kg / 6.67 N
Magnetic Induction ~ ?
237.19 mT
Coating
[NiCuNi] nickel
Manufacturing Tolerance
± 0.1 mm

Magnetic properties of material N38

properties
values
units
remenance Br [Min. - Max.] ?
12.2-12.6
kGs
remenance Br [Min. - Max.] ?
1220-1260
T
coercivity bHc ?
10.8-11.5
kOe
coercivity bHc ?
860-915
kA/m
actual internal force iHc
≥ 12
kOe
actual internal force iHc
≥ 955
kA/m
energy density [Min. - Max.] ?
36-38
BH max MGOe
energy density [Min. - Max.] ?
287-303
BH max KJ/m
max. temperature ?
≤ 80
°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
312 - 380
°C
Curie Temperature TF
593 - 716
°F
Specific resistance
150
μΩ⋅Cm
Bending strength
250
Mpa
Compressive strength
1000~1100
Mpa
Thermal expansion parallel (∥) to orientation (M)
(3-4) x 106
°C-1
Thermal expansion perpendicular (⊥) to orientation (M)
-(1-3) x 10-6
°C-1
Young's modulus
1.7 x 104
kg/mm²

Shopping tips

The ring magnet with a hole MP 12x8/4x3 / N38 is created for permanent mounting, where glue might fail or be insufficient. Thanks to the hole (often for a screw), this model enables easy screwing to wood, wall, plastic, or metal. This product with a force of 0.68 kg works great as a door latch, speaker holder, or mounting element in devices.
This is a crucial issue when working with model MP 12x8/4x3 / N38. Neodymium magnets are sintered ceramics, which means they are hard but breakable and inelastic. When tightening the screw, you must maintain great sensitivity. We recommend tightening manually with a screwdriver, not an impact driver, because too much pressure will cause the ring to crack. It's a good idea to use a flexible washer under the screw head, which will cushion the stresses. Remember: cracking during assembly results from material properties, not a product defect.
Moisture can penetrate micro-cracks in the coating and cause oxidation of the magnet. Damage to the protective layer during assembly is the most common cause of rusting. If you must use it outside, paint it with anti-corrosion paint after mounting.
A screw or bolt with a thread diameter smaller than 8/4 mm fits this model. If the magnet does not have a chamfer (cone), we recommend using a screw with a flat or cylindrical head, or possibly using a washer. Aesthetic mounting requires selecting the appropriate head size.
This model is characterized by dimensions Ø12x3 mm and a weight of 4.24 g. The key parameter here is the lifting capacity amounting to approximately 0.68 kg (force ~6.67 N). The mounting hole diameter is precisely 8/4 mm.
The poles are located on the planes with holes, not on the sides of the ring. If you want two such magnets screwed with cones facing each other (faces) to attract, you must connect them with opposite poles (N to S). When ordering a larger quantity, magnets are usually packed in stacks, where they are already naturally paired.

Advantages and disadvantages of neodymium magnets.

Besides their immense pulling force, neodymium magnets offer the following advantages:

  • They have constant strength, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
  • They do not lose their magnetic properties even under strong external field,
  • A magnet with a shiny silver surface has better aesthetics,
  • The surface of neodymium magnets generates a concentrated magnetic field – this is a distinguishing feature,
  • Due to their durability and thermal resistance, neodymium magnets can operate (depending on the shape) even at high temperatures reaching 230°C or more...
  • Possibility of exact machining and adjusting to concrete needs,
  • Fundamental importance in high-tech industry – they are commonly used in hard drives, electric motors, medical devices, and modern systems.
  • Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which enables their usage in miniature devices

What to avoid - cons of neodymium magnets: weaknesses and usage proposals

  • To avoid cracks upon strong impacts, we suggest using special steel housings. Such a solution secures the magnet and simultaneously improves its durability.
  • Neodymium magnets lose power when exposed to high temperatures. After reaching 80°C, many of them experience permanent drop of strength (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 suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, in case of application outdoors
  • We suggest a housing - magnetic holder, due to difficulties in realizing threads inside the magnet and complex shapes.
  • Health risk related to microscopic parts of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that tiny parts of these magnets are able to be problematic in diagnostics medical when they are in the body.
  • Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Magnetic strength at its maximum – what affects it?

Holding force of 0.68 kg is a result of laboratory testing conducted under the following configuration:

  • on a block made of structural steel, optimally conducting the magnetic field
  • whose transverse dimension is min. 10 mm
  • with an ground touching surface
  • under conditions of gap-free contact (surface-to-surface)
  • under perpendicular application of breakaway force (90-degree angle)
  • in temp. approx. 20°C

What influences lifting capacity in practice

Effective lifting capacity impacted by specific conditions, mainly (from most important):

  • Air gap (between the magnet and the metal), as even a tiny distance (e.g. 0.5 mm) can cause a decrease in lifting capacity by up to 50% (this also applies to paint, corrosion or debris).
  • Loading method – declared lifting capacity refers to pulling vertically. When attempting to slide, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
  • Plate thickness – too thin sheet does not close the flux, causing part of the flux to be wasted to the other side.
  • Material type – the best choice is high-permeability steel. Cast iron may have worse magnetic properties.
  • Surface structure – the more even the plate, the better the adhesion and higher the lifting capacity. Roughness creates an air distance.
  • Temperature – temperature increase causes a temporary drop of force. It is worth remembering the thermal limit for a given model.

* Holding force was checked on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the load capacity is reduced by as much as fivefold. Moreover, even a minimal clearance {between} the magnet and the plate decreases the holding force.

Warnings

Danger to the youngest

Only for adults. Small elements can be swallowed, causing severe trauma. Store away from kids and pets.

Operating temperature

Monitor thermal conditions. Heating the magnet above 80 degrees Celsius will destroy its magnetic structure and pulling force.

Serious injuries

Watch your fingers. Two powerful magnets will snap together immediately with a force of several hundred kilograms, destroying anything in their path. Be careful!

Keep away from computers

Avoid bringing magnets near a purse, laptop, or TV. The magnetic field can irreversibly ruin these devices and wipe information from cards.

Metal Allergy

Some people have a sensitization to nickel, which is the common plating for NdFeB magnets. Prolonged contact can result in skin redness. We recommend wear safety gloves.

Powerful field

Before use, read the rules. Sudden snapping can break the magnet or injure your hand. Think ahead.

Beware of splinters

Despite metallic appearance, the material is delicate and cannot withstand shocks. Do not hit, as the magnet may shatter into sharp, dangerous pieces.

Do not drill into magnets

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

Danger to pacemakers

Patients with a ICD should keep an absolute distance from magnets. The magnetism can stop the operation of the life-saving device.

Impact on smartphones

Navigation devices and smartphones are highly susceptible to magnetism. Close proximity with a powerful NdFeB magnet can permanently damage the internal compass in your phone.

Important!

Looking for details? Read our article: Why are neodymium magnets dangerous?

Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98