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
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Detailed specification - 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 simulation of the magnet - data
Presented values represent the result of a mathematical analysis. Values are based on algorithms for the material Nd2Fe14B. Operational conditions might slightly differ. Treat these data as a supplementary guide for designers.
Table 1: Static pull force (force vs distance) - interaction chart
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
|
strong |
| 1 mm |
5321 Gs
532.1 mT
|
5.84 kg / 12.87 pounds
5839.8 g / 57.3 N
|
strong |
| 2 mm |
4736 Gs
473.6 mT
|
4.63 kg / 10.20 pounds
4626.6 g / 45.4 N
|
strong |
| 3 mm |
4184 Gs
418.4 mT
|
3.61 kg / 7.96 pounds
3610.0 g / 35.4 N
|
strong |
| 5 mm |
3216 Gs
321.6 mT
|
2.13 kg / 4.70 pounds
2132.9 g / 20.9 N
|
strong |
| 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: Sliding load (wall)
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 (sliding) - 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: Steel thickness (saturation) - 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 stability (material behavior) - power drop
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 (attraction) - forces in the system
MP 20x8x6 / N38
| Gap (mm) | Attraction (kg/lbs) (N-S) | Shear Strength (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) - precautionary measures
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: Impact energy (kinetic energy) - collision effects
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: Anti-corrosion coating durability
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: Construction data (Flux)
MP 20x8x6 / N38
| Parameter | Value | SI Unit / Description |
|---|---|---|
| Magnetic Flux | 15 688 Mx | 156.9 µWb |
| Pc Coefficient | 1.14 | High (Stable) |
Table 11: Underwater work (magnet fishing)
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. Wall mount (shear)
*Caution: On a vertical wall, the magnet holds only ~20% of its nominal pull.
2. Steel thickness impact
*Thin metal sheet (e.g. computer case) drastically reduces the holding force.
3. Heat tolerance
*For standard magnets, the max working temp 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.
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% |
Environmental data
| recyclability (EoL) | 100% |
| recycled raw materials | ~10% (pre-cons) |
| carbon footprint | low / zredukowany |
| waste code (EWC) | 16 02 16 |
View also products
Advantages and disadvantages of neodymium magnets.
Advantages
- They do not lose magnetism, even over nearly ten years – the drop in power is only ~1% (based on measurements),
- They do not lose their magnetic properties even under external field action,
- The use of an shiny layer of noble metals (nickel, gold, silver) causes the element to have aesthetics,
- Neodymium magnets deliver maximum magnetic induction on a small surface, which ensures high operational effectiveness,
- Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can work (depending on the shape) even at a temperature of 230°C or more...
- Possibility of accurate creating as well as adapting to concrete applications,
- Huge importance in modern technologies – they serve a role in HDD drives, electric drive systems, precision medical tools, also other advanced devices.
- Compactness – despite small sizes they generate large force, making them ideal for precision applications
Limitations
- Susceptibility to cracking is one of their disadvantages. Upon intense impact they can fracture. We advise keeping them in a special holder, which not only secures them against impacts but also raises their durability
- We warn that neodymium magnets can lose their strength at high temperatures. To prevent this, we recommend our specialized [AH] magnets, which work effectively even at 230°C.
- Magnets exposed to a humid environment can corrode. Therefore while using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
- Due to limitations in producing threads and complex shapes in magnets, we propose using cover - magnetic holder.
- Health risk related to microscopic parts of magnets are risky, when accidentally swallowed, which is particularly important in the context of child safety. Furthermore, tiny parts of these devices can be problematic in diagnostics medical when they are in the body.
- Due to neodymium price, their price is relatively high,
Pull force analysis
Optimal lifting capacity of a neodymium magnet – what affects it?
- on a block made of mild steel, effectively closing the magnetic flux
- whose thickness equals approx. 10 mm
- with a plane free of scratches
- without any insulating layer between the magnet and steel
- during pulling in a direction perpendicular to the mounting surface
- in neutral thermal conditions
Practical lifting capacity: influencing factors
- Clearance – existence of any layer (rust, dirt, air) interrupts the magnetic circuit, which lowers capacity steeply (even by 50% at 0.5 mm).
- Force direction – catalog parameter refers to detachment vertically. When applying parallel force, the magnet holds much less (typically approx. 20-30% of maximum force).
- Wall thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of converting into lifting capacity.
- Steel grade – the best choice is high-permeability steel. Cast iron may attract less.
- Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Rough surfaces weaken the grip.
- Temperature – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.
Lifting capacity was assessed by applying a steel plate with a smooth surface of suitable thickness (min. 20 mm), under perpendicular pulling force, however under parallel forces the lifting capacity is smaller. Moreover, even a small distance between the magnet and the plate decreases the holding force.
Safety rules for work with NdFeB magnets
Warning for heart patients
Patients with a ICD have to maintain an absolute distance from magnets. The magnetism can disrupt the functioning of the implant.
Respect the power
Handle magnets with awareness. Their powerful strength can shock even professionals. Be vigilant and do not underestimate their power.
Magnet fragility
NdFeB magnets are ceramic materials, which means they are very brittle. Impact of two magnets leads to them breaking into small pieces.
Precision electronics
Note: neodymium magnets produce a field that confuses sensitive sensors. Maintain a separation from your phone, device, and GPS.
Safe distance
Avoid bringing magnets near a wallet, laptop, or TV. The magnetic field can irreversibly ruin these devices and wipe information from cards.
Nickel coating and allergies
Some people have a sensitization to nickel, which is the typical protective layer for neodymium magnets. Extended handling might lead to dermatitis. We suggest wear safety gloves.
Heat warning
Control the heat. Exposing the magnet to high heat will ruin its properties and pulling force.
Keep away from children
These products are not toys. Swallowing several magnets may result in them connecting inside the digestive tract, which constitutes a severe health hazard and necessitates immediate surgery.
Bone fractures
Pinching hazard: The attraction force is so immense that it can cause blood blisters, crushing, and broken bones. Protective gloves are recommended.
Dust is flammable
Drilling and cutting of neodymium magnets poses a fire hazard. Magnetic powder reacts violently with oxygen and is difficult to extinguish.
