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MP 20x8x6 / N38 - ring magnet

ring magnet

Catalog no 030189

GTIN/EAN: 5906301812067

5.00

Diameter

20 mm [±0,1 mm]

internal diameter Ø

8 mm [±0,1 mm]

Height

6 mm [±0,1 mm]

Weight

11.88 g

Magnetization Direction

↑ axial

Load capacity

7.22 kg / 70.81 N

Magnetic Induction

318.85 mT / 3188 Gs

Coating

[NiCuNi] Nickel

5.17 with VAT / pcs + price for transport

4.20 ZŁ net + 23% VAT / pcs

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Technical data - MP 20x8x6 / N38 - ring magnet

Specification / characteristics - MP 20x8x6 / N38 - ring magnet

properties
properties values
Cat. no. 030189
GTIN/EAN 5906301812067
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 20 mm [±0,1 mm]
internal diameter Ø 8 mm [±0,1 mm]
Height 6 mm [±0,1 mm]
Weight 11.88 g
Magnetization Direction ↑ axial
Load capacity ~ ? 7.22 kg / 70.81 N
Magnetic Induction ~ ? 318.85 mT / 3188 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 20x8x6 / N38 - ring magnet
properties values units
remenance Br [min. - max.] ? 12.2-12.6 kGs
remenance Br [min. - max.] ? 1220-1260 mT
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

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 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

Technical analysis of the magnet - report

The following values constitute the outcome of a mathematical simulation. Results are based on algorithms for the material Nd2Fe14B. Operational conditions might slightly differ from theoretical values. Please consider these calculations as a preliminary roadmap for designers.

Table 1: Static force (force vs distance) - characteristics
MP 20x8x6 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 5917 Gs
591.7 mT
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
medium risk
1 mm 5321 Gs
532.1 mT
5.84 kg / 12.87 pounds
5839.8 g / 57.3 N
medium risk
2 mm 4736 Gs
473.6 mT
4.63 kg / 10.20 pounds
4626.6 g / 45.4 N
medium risk
3 mm 4184 Gs
418.4 mT
3.61 kg / 7.96 pounds
3610.0 g / 35.4 N
medium risk
5 mm 3216 Gs
321.6 mT
2.13 kg / 4.70 pounds
2132.9 g / 20.9 N
medium risk
10 mm 1650 Gs
165.0 mT
0.56 kg / 1.24 pounds
561.3 g / 5.5 N
low risk
15 mm 907 Gs
90.7 mT
0.17 kg / 0.37 pounds
169.7 g / 1.7 N
low risk
20 mm 544 Gs
54.4 mT
0.06 kg / 0.13 pounds
61.1 g / 0.6 N
low risk
30 mm 240 Gs
24.0 mT
0.01 kg / 0.03 pounds
11.9 g / 0.1 N
low risk
50 mm 75 Gs
7.5 mT
0.00 kg / 0.00 pounds
1.2 g / 0.0 N
low risk

Table 2: Slippage force (vertical surface)
MP 20x8x6 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 1.44 kg / 3.18 pounds
1444.0 g / 14.2 N
1 mm Stal (~0.2) 1.17 kg / 2.57 pounds
1168.0 g / 11.5 N
2 mm Stal (~0.2) 0.93 kg / 2.04 pounds
926.0 g / 9.1 N
3 mm Stal (~0.2) 0.72 kg / 1.59 pounds
722.0 g / 7.1 N
5 mm Stal (~0.2) 0.43 kg / 0.94 pounds
426.0 g / 4.2 N
10 mm Stal (~0.2) 0.11 kg / 0.25 pounds
112.0 g / 1.1 N
15 mm Stal (~0.2) 0.03 kg / 0.07 pounds
34.0 g / 0.3 N
20 mm Stal (~0.2) 0.01 kg / 0.03 pounds
12.0 g / 0.1 N
30 mm Stal (~0.2) 0.00 kg / 0.00 pounds
2.0 g / 0.0 N
50 mm Stal (~0.2) 0.00 kg / 0.00 pounds
0.0 g / 0.0 N

Table 3: Vertical assembly (shearing) - behavior on slippery surfaces
MP 20x8x6 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
2.17 kg / 4.78 pounds
2166.0 g / 21.2 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
1.44 kg / 3.18 pounds
1444.0 g / 14.2 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
0.72 kg / 1.59 pounds
722.0 g / 7.1 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
3.61 kg / 7.96 pounds
3610.0 g / 35.4 N

Table 4: Material efficiency (substrate influence) - power losses
MP 20x8x6 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
10%
0.72 kg / 1.59 pounds
722.0 g / 7.1 N
1 mm
25%
1.81 kg / 3.98 pounds
1805.0 g / 17.7 N
2 mm
50%
3.61 kg / 7.96 pounds
3610.0 g / 35.4 N
3 mm
75%
5.42 kg / 11.94 pounds
5415.0 g / 53.1 N
5 mm
100%
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
10 mm
100%
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
11 mm
100%
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
12 mm
100%
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N

Table 5: Thermal resistance (material behavior) - thermal limit
MP 20x8x6 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
OK
40 °C -2.2% 7.06 kg / 15.57 pounds
7061.2 g / 69.3 N
OK
60 °C -4.4% 6.90 kg / 15.22 pounds
6902.3 g / 67.7 N
OK
80 °C -6.6% 6.74 kg / 14.87 pounds
6743.5 g / 66.2 N
100 °C -28.8% 5.14 kg / 11.33 pounds
5140.6 g / 50.4 N

Table 6: Magnet-Magnet interaction (repulsion) - forces in the system
MP 20x8x6 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Lateral Force (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 52.44 kg / 115.62 pounds
6 121 Gs
7.87 kg / 17.34 pounds
7867 g / 77.2 N
N/A
1 mm 47.33 kg / 104.35 pounds
11 242 Gs
7.10 kg / 15.65 pounds
7100 g / 69.6 N
42.60 kg / 93.91 pounds
~0 Gs
2 mm 42.42 kg / 93.52 pounds
10 642 Gs
6.36 kg / 14.03 pounds
6363 g / 62.4 N
38.18 kg / 84.16 pounds
~0 Gs
3 mm 37.84 kg / 83.42 pounds
10 051 Gs
5.68 kg / 12.51 pounds
5675 g / 55.7 N
34.05 kg / 75.07 pounds
~0 Gs
5 mm 29.73 kg / 65.55 pounds
8 910 Gs
4.46 kg / 9.83 pounds
4460 g / 43.8 N
26.76 kg / 59.00 pounds
~0 Gs
10 mm 15.49 kg / 34.16 pounds
6 432 Gs
2.32 kg / 5.12 pounds
2324 g / 22.8 N
13.94 kg / 30.74 pounds
~0 Gs
20 mm 4.08 kg / 8.99 pounds
3 299 Gs
0.61 kg / 1.35 pounds
612 g / 6.0 N
3.67 kg / 8.09 pounds
~0 Gs
50 mm 0.18 kg / 0.41 pounds
702 Gs
0.03 kg / 0.06 pounds
28 g / 0.3 N
0.17 kg / 0.37 pounds
~0 Gs
60 mm 0.09 kg / 0.19 pounds
480 Gs
0.01 kg / 0.03 pounds
13 g / 0.1 N
0.08 kg / 0.17 pounds
~0 Gs
70 mm 0.04 kg / 0.10 pounds
342 Gs
0.01 kg / 0.01 pounds
7 g / 0.1 N
0.04 kg / 0.09 pounds
~0 Gs
80 mm 0.02 kg / 0.05 pounds
253 Gs
0.00 kg / 0.01 pounds
4 g / 0.0 N
0.02 kg / 0.05 pounds
~0 Gs
90 mm 0.01 kg / 0.03 pounds
193 Gs
0.00 kg / 0.00 pounds
2 g / 0.0 N
0.01 kg / 0.03 pounds
~0 Gs
100 mm 0.01 kg / 0.02 pounds
150 Gs
0.00 kg / 0.00 pounds
1 g / 0.0 N
0.00 kg / 0.00 pounds
~0 Gs

Table 7: Protective zones (electronics) - warnings
MP 20x8x6 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 14.5 cm
Hearing aid 10 Gs (1.0 mT) 11.5 cm
Mechanical watch 20 Gs (2.0 mT) 9.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 6.5 cm
Remote 50 Gs (5.0 mT) 6.0 cm
Payment card 400 Gs (40.0 mT) 2.5 cm
HDD hard drive 600 Gs (60.0 mT) 2.0 cm

Table 8: Collisions (cracking risk) - warning
MP 20x8x6 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 26.04 km/h
(7.23 m/s)
0.31 J
30 mm 43.11 km/h
(11.97 m/s)
0.85 J
50 mm 55.60 km/h
(15.44 m/s)
1.42 J
100 mm 78.62 km/h
(21.84 m/s)
2.83 J

Table 9: Surface protection spec
MP 20x8x6 / N38

Technical parameter Value / Description
Coating type [NiCuNi] Nickel
Layer structure Nickel - Copper - Nickel
Layer thickness 10-20 µm
Salt spray test (SST) ? 24 h
Recommended environment Indoors only (dry)

Table 10: Electrical data (Pc)
MP 20x8x6 / N38

Parameter Value SI Unit / Description
Magnetic Flux 15 688 Mx 156.9 µWb
Pc Coefficient 1.14 High (Stable)

Table 11: Hydrostatics and buoyancy
MP 20x8x6 / N38

Environment Effective steel pull Effect
Air (land) 7.22 kg Standard
Water (riverbed) 8.27 kg
(+1.05 kg buoyancy gain)
+14.5%
Rust risk: Standard nickel requires drying after every contact with moisture; lack of maintenance will lead to rust spots.
1. Sliding resistance

*Warning: On a vertical wall, the magnet retains only a fraction of its max power.

2. Efficiency vs thickness

*Thin steel (e.g. computer case) severely weakens the holding force.

3. Temperature resistance

*For standard magnets, the safety limit is 80°C.

4. Demagnetization curve and operating point (B-H)

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 1.14

This simulation demonstrates the magnetic stability of the selected magnet under specific geometric conditions. The solid red line represents the demagnetization curve (material potential), while the dashed blue line is the load line based on the magnet's geometry. The Pc (Permeance Coefficient), also known as the load line slope, is a dimensionless value that describes the relationship between the magnet's shape and its magnetic stability. The intersection of these two lines (the black dot) is the operating point — it determines the actual magnetic flux density generated by the magnet in this specific configuration. A higher Pc value means the magnet is more 'slender' (tall relative to its area), resulting in a higher operating point and better resistance to irreversible demagnetization caused by external fields or temperature. A value of 0.42 is relatively low (typical for flat magnets), meaning the operating point is closer to the 'knee' of the curve — caution is advised when operating at temperatures near the maximum limit to avoid strength loss.

Technical and environmental data
Elemental analysis
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%
Sustainability
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: 030189-2026
Magnet Unit Converter
Pulling force

Magnetic Field

Other offers

The ring-shaped magnet MP 20x8x6 / N38 is created for mechanical fastening, where glue might fail or be insufficient. Mounting is clean and reversible, unlike gluing. This product with a force of 7.22 kg works great as a cabinet closure, speaker holder, or mounting element in devices.
This material behaves more like porcelain than steel, so it doesn't forgive mistakes during mounting. When tightening the screw, you must maintain caution. We recommend tightening manually with a screwdriver, not an impact driver, because excessive force will cause the ring to crack. The flat screw head should evenly press the magnet. Remember: cracking during assembly results from material properties, not a product defect.
These magnets are coated with standard Ni-Cu-Ni plating, which protects them in indoor conditions, but does not ensure full waterproofing. 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.
The inner hole diameter determines the maximum size of the mounting element. 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.
It is a magnetic ring with a diameter of 20 mm and thickness 6 mm. The pulling force of this model is an impressive 7.22 kg, which translates to 70.81 N in newtons. The product has a [NiCuNi] coating and is made of NdFeB material. Inner hole dimension: 8 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.

Pros and cons of rare earth magnets.

Pros

In addition to their magnetic capacity, neodymium magnets provide the following advantages:
  • They retain full power for almost 10 years – the loss is just ~1% (in theory),
  • They are noted for resistance to demagnetization induced by external magnetic fields,
  • Thanks to the metallic finish, the coating of nickel, gold-plated, or silver-plated gives an clean appearance,
  • The surface of neodymium magnets generates a powerful 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...
  • Possibility of exact modeling and optimizing to atypical conditions,
  • Wide application in electronics industry – they serve a role in magnetic memories, electric drive systems, medical equipment, and complex engineering applications.
  • Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Disadvantages

Problematic aspects of neodymium magnets: tips and applications.
  • Brittleness is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a steel housing, which not only protects them against impacts but also increases their durability
  • When exposed to high temperature, neodymium magnets suffer a drop in force. Often, when the temperature exceeds 80°C, their strength decreases (depending on the size, as well as shape of the magnet). For those who need magnets for extreme conditions, we offer [AH] versions withstanding up to 230°C
  • 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
  • We suggest a housing - magnetic mechanism, due to difficulties in realizing nuts inside the magnet and complex shapes.
  • Possible danger to health – tiny shards of magnets are risky, if swallowed, which gains importance in the context of child safety. Furthermore, small elements of these magnets are able to complicate diagnosis medical in case of swallowing.
  • High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Lifting parameters

Optimal lifting capacity of a neodymium magnetwhat it depends on?

The load parameter shown concerns the maximum value, recorded under laboratory conditions, specifically:
  • on a block made of structural steel, effectively closing the magnetic field
  • whose transverse dimension is min. 10 mm
  • with an ground contact surface
  • without any air gap between the magnet and steel
  • during detachment in a direction perpendicular to the mounting surface
  • at standard ambient temperature

Lifting capacity in practice – influencing factors

It is worth knowing that the working load will differ depending on the following factors, in order of importance:
  • Clearance – existence of any layer (paint, dirt, gap) acts as an insulator, which lowers capacity rapidly (even by 50% at 0.5 mm).
  • Angle of force application – maximum parameter is available only during perpendicular pulling. The shear force of the magnet along the plate is standardly several times smaller (approx. 1/5 of the lifting capacity).
  • Plate thickness – too thin steel does not close the flux, causing part of the power to be wasted to the other side.
  • Material type – ideal substrate is high-permeability steel. Stainless steels may have worse magnetic properties.
  • Surface quality – the more even the plate, the larger the contact zone and stronger the hold. Unevenness acts like micro-gaps.
  • Temperature influence – high temperature weakens magnetic field. Too high temperature can permanently damage the magnet.

Holding force was tested on a smooth steel plate of 20 mm thickness, when the force acted perpendicularly, whereas under parallel forces the load capacity is reduced by as much as 5 times. Moreover, even a small distance between the magnet and the plate decreases the holding force.

Safe handling of NdFeB magnets
Danger to the youngest

Always keep magnets away from children. Risk of swallowing is high, and the consequences of magnets clamping inside the body are tragic.

Do not overheat magnets

Monitor thermal conditions. Heating the magnet above 80 degrees Celsius will ruin its properties and strength.

Physical harm

Big blocks can break fingers instantly. Do not place your hand between two strong magnets.

Handling guide

Handle magnets consciously. Their huge power can surprise even experienced users. Be vigilant and do not underestimate their force.

Metal Allergy

A percentage of the population experience a contact allergy to Ni, which is the common plating for NdFeB magnets. Prolonged contact might lead to dermatitis. We suggest wear safety gloves.

GPS and phone interference

Navigation devices and smartphones are highly sensitive to magnetism. Close proximity with a powerful NdFeB magnet can ruin the sensors in your phone.

Magnets are brittle

NdFeB magnets are ceramic materials, meaning they are very brittle. Clashing of two magnets leads to them shattering into small pieces.

Life threat

Medical warning: Neodymium magnets can turn off heart devices and defibrillators. Stay away if you have electronic implants.

Dust explosion hazard

Machining of neodymium magnets poses a fire hazard. Neodymium dust oxidizes rapidly with oxygen and is hard to extinguish.

Protect data

Device Safety: Strong magnets can damage payment cards and delicate electronics (pacemakers, medical aids, timepieces).

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