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neodymium magnets

We provide blue color magnets Nd2Fe14B - our proposal. All magnesy neodymowe on our website are available for immediate purchase (see the list). Check out the magnet pricing for more details check the magnet price list

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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 mechanical fastening, 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. It is also often used in advertising for fixing signs and in workshops for organizing tools.
This material behaves more like porcelain than steel, so it doesn't forgive mistakes during mounting. 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 rubber spacer 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. In the place of the mounting hole, the coating is thinner and can be damaged when tightening the screw, which will become a corrosion focus. 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. For magnets with a straight hole, a conical head can act like a wedge and burst the magnet. Aesthetic mounting requires selecting the appropriate head size.
It is a magnetic ring with a diameter of 12 mm and thickness 3 mm. The pulling force of this model is an impressive 0.68 kg, which translates to 6.67 N in newtons. The product has a [NiCuNi] coating and is made of NdFeB material. Inner hole dimension: 8/4 mm.
The poles are located on the planes with holes, not on the sides of the ring. In the case of connecting two rings, make sure one is turned the right way. 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 remarkable field intensity, neodymium magnets offer the following advantages:

  • They have constant strength, and over nearly 10 years their attraction force decreases symbolically – ~1% (according to theory),
  • They possess excellent resistance to weakening of magnetic properties when exposed to opposing magnetic fields,
  • In other words, due to the smooth layer of nickel, the element becomes visually attractive,
  • They are known for high magnetic induction at the operating surface, which increases their power,
  • Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the form) even at high temperatures reaching 230°C or more...
  • Thanks to flexibility in shaping and the ability to adapt to unusual requirements,
  • Universal use in innovative solutions – they are used in hard drives, brushless drives, diagnostic systems, also multitasking production systems.
  • Relatively small size with high pulling force – neodymium magnets offer strong magnetic field in small dimensions, which makes them useful in compact constructions

Drawbacks and weaknesses of neodymium magnets: weaknesses and usage proposals

  • To avoid cracks under impact, we recommend using special steel housings. Such a solution secures the magnet and simultaneously increases its durability.
  • Neodymium magnets demagnetize 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 suggest using waterproof magnets made of rubber, plastic or other material stable to moisture, when using outdoors
  • Due to limitations in creating nuts and complex shapes in magnets, we propose using a housing - magnetic mount.
  • Health risk to health – tiny shards of magnets are risky, if swallowed, which gains importance in the context of child safety. It is also worth noting that small elements of these devices are able to disrupt the diagnostic process medical after entering the body.
  • Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Highest magnetic holding forcewhat affects it?

The declared magnet strength concerns the limit force, measured under optimal environment, specifically:

  • on a plate made of mild steel, effectively closing the magnetic field
  • with a thickness no less than 10 mm
  • characterized by lack of roughness
  • without any air gap between the magnet and steel
  • during pulling in a direction vertical to the mounting surface
  • at room temperature

Magnet lifting force in use – key factors

During everyday use, the real power results from several key aspects, ranked from most significant:

  • Distance – existence of foreign body (paint, dirt, air) acts as an insulator, which lowers power rapidly (even by 50% at 0.5 mm).
  • Pull-off angle – remember that the magnet has greatest strength perpendicularly. Under shear forces, the capacity drops drastically, often to levels of 20-30% of the nominal value.
  • Plate thickness – insufficiently thick steel causes magnetic saturation, causing part of the power to be escaped to the other side.
  • Material type – the best choice is pure iron steel. Hardened steels may generate lower lifting capacity.
  • Surface finish – ideal contact is obtained only on smooth steel. Rough texture reduce the real contact area, reducing force.
  • Operating temperature – NdFeB sinters have a negative temperature coefficient. At higher temperatures they are weaker, and in frost gain strength (up to a certain limit).

* Lifting capacity testing was conducted on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, whereas under shearing force the holding force is lower. In addition, even a slight gap {between} the magnet and the plate lowers the holding force.

Safety rules for work with neodymium magnets

Cards and drives

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

This is not a toy

Neodymium magnets are not intended for children. Eating multiple magnets can lead to them connecting inside the digestive tract, which poses a critical condition and necessitates urgent medical intervention.

Bodily injuries

Danger of trauma: The attraction force is so immense that it can cause blood blisters, pinching, and even bone fractures. Use thick gloves.

Maximum temperature

Standard neodymium magnets (grade N) undergo demagnetization when the temperature exceeds 80°C. This process is irreversible.

Risk of cracking

Despite the nickel coating, the material is brittle and cannot withstand shocks. Do not hit, as the magnet may shatter into sharp, dangerous pieces.

Precision electronics

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

Handling guide

Before starting, read the rules. Sudden snapping can destroy the magnet or injure your hand. Be predictive.

Skin irritation risks

Medical facts indicate that the nickel plating (standard magnet coating) is a potent allergen. If your skin reacts to metals, avoid touching magnets with bare hands or opt for versions in plastic housing.

Dust is flammable

Drilling and cutting of NdFeB material carries a risk of fire risk. Magnetic powder reacts violently with oxygen and is difficult to extinguish.

ICD Warning

Warning for patients: Powerful magnets disrupt electronics. Maintain at least 30 cm distance or ask another person to work with the magnets.

Important!

Need more info? Check our post: Why are neodymium magnets dangerous?

Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98