MP 20x8x6 / N38 - ring magnet
ring magnet
Catalog no 030189
GTIN/EAN: 5906301812067
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 ZŁ with VAT / pcs + price for transport
4.20 ZŁ net + 23% VAT / pcs
bulk discounts:
Need more?
Contact us by phone
+48 888 99 98 98
alternatively send us a note through
request form
our website.
Weight along with shape of magnets can be calculated with our
modular calculator.
Orders submitted before 14:00 will be dispatched today!
Technical data - MP 20x8x6 / N38 - ring magnet
Specification / characteristics - MP 20x8x6 / N38 - ring magnet
| properties | values |
|---|---|
| Cat. no. | 030189 |
| GTIN/EAN | 5906301812067 |
| Production/Distribution | Dhit sp. z o.o. |
| 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
| 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
| 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 |
|
0.72 kg / 1.59 pounds
722.0 g / 7.1 N
|
| 1 mm |
|
1.81 kg / 3.98 pounds
1805.0 g / 17.7 N
|
| 2 mm |
|
3.61 kg / 7.96 pounds
3610.0 g / 35.4 N
|
| 3 mm |
|
5.42 kg / 11.94 pounds
5415.0 g / 53.1 N
|
| 5 mm |
|
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
|
| 10 mm |
|
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
|
| 11 mm |
|
7.22 kg / 15.92 pounds
7220.0 g / 70.8 N
|
| 12 mm |
|
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% |
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.
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 |
Other offers
Pros and cons of rare earth magnets.
Pros
- 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
- 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 magnet – what it depends on?
- 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
- 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).
