MP 12x8/4x3 / N38 - ring magnet
ring magnet
Catalog no 030395
GTIN/EAN: 5906301812326
Diameter
12 mm [±0,1 mm]
internal diameter Ø
8/4 mm [±0,1 mm]
Height
3 mm [±0,1 mm]
Weight
2.26 g
Magnetization Direction
↑ axial
Load capacity
2.21 kg / 21.72 N
Magnetic Induction
277.09 mT / 2771 Gs
Coating
[NiCuNi] Nickel
1.427 ZŁ 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/EAN | 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 | 2.26 g |
| Magnetization Direction | ↑ axial |
| Load capacity ~ ? | 2.21 kg / 21.72 N |
| Magnetic Induction ~ ? | 277.09 mT / 2771 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 |
Physical simulation of the product - data
The following data constitute the outcome of a mathematical analysis. Results rely on models for the material Nd2Fe14B. Actual performance may differ from theoretical values. Use these calculations as a reference point when designing systems.
MP 12x8/4x3 / N38
| Distance (mm) | Induction (Gauss) / mT | Pull Force (kg) | Risk Status |
|---|---|---|---|
| 0 mm |
2423 Gs
242.3 mT
|
2.21 kg / 2210.0 g
21.7 N
|
medium risk |
| 1 mm |
2138 Gs
213.8 mT
|
1.72 kg / 1720.7 g
16.9 N
|
low risk |
| 2 mm |
1786 Gs
178.6 mT
|
1.20 kg / 1200.5 g
11.8 N
|
low risk |
| 3 mm |
1437 Gs
143.7 mT
|
0.78 kg / 777.8 g
7.6 N
|
low risk |
| 5 mm |
885 Gs
88.5 mT
|
0.29 kg / 294.7 g
2.9 N
|
low risk |
| 10 mm |
277 Gs
27.7 mT
|
0.03 kg / 28.9 g
0.3 N
|
low risk |
| 15 mm |
110 Gs
11.0 mT
|
0.00 kg / 4.6 g
0.0 N
|
low risk |
| 20 mm |
53 Gs
5.3 mT
|
0.00 kg / 1.1 g
0.0 N
|
low risk |
| 30 mm |
18 Gs
1.8 mT
|
0.00 kg / 0.1 g
0.0 N
|
low risk |
| 50 mm |
4 Gs
0.4 mT
|
0.00 kg / 0.0 g
0.0 N
|
low risk |
MP 12x8/4x3 / N38
| Distance (mm) | Friction coefficient | Pull Force (kg) |
|---|---|---|
| 0 mm | Stal (~0.2) |
0.44 kg / 442.0 g
4.3 N
|
| 1 mm | Stal (~0.2) |
0.34 kg / 344.0 g
3.4 N
|
| 2 mm | Stal (~0.2) |
0.24 kg / 240.0 g
2.4 N
|
| 3 mm | Stal (~0.2) |
0.16 kg / 156.0 g
1.5 N
|
| 5 mm | Stal (~0.2) |
0.06 kg / 58.0 g
0.6 N
|
| 10 mm | Stal (~0.2) |
0.01 kg / 6.0 g
0.1 N
|
| 15 mm | Stal (~0.2) |
0.00 kg / 0.0 g
0.0 N
|
| 20 mm | Stal (~0.2) |
0.00 kg / 0.0 g
0.0 N
|
| 30 mm | Stal (~0.2) |
0.00 kg / 0.0 g
0.0 N
|
| 50 mm | Stal (~0.2) |
0.00 kg / 0.0 g
0.0 N
|
MP 12x8/4x3 / N38
| Surface type | Friction coefficient / % Mocy | Max load (kg) |
|---|---|---|
| Raw steel |
µ = 0.3
30% Nominalnej Siły
|
0.66 kg / 663.0 g
6.5 N
|
| Painted steel (standard) |
µ = 0.2
20% Nominalnej Siły
|
0.44 kg / 442.0 g
4.3 N
|
| Oily/slippery steel |
µ = 0.1
10% Nominalnej Siły
|
0.22 kg / 221.0 g
2.2 N
|
| Magnet with anti-slip rubber |
µ = 0.5
50% Nominalnej Siły
|
1.11 kg / 1105.0 g
10.8 N
|
MP 12x8/4x3 / N38
| Steel thickness (mm) | % power | Real pull force (kg) |
|---|---|---|
| 0.5 mm |
|
0.22 kg / 221.0 g
2.2 N
|
| 1 mm |
|
0.55 kg / 552.5 g
5.4 N
|
| 2 mm |
|
1.11 kg / 1105.0 g
10.8 N
|
| 5 mm |
|
2.21 kg / 2210.0 g
21.7 N
|
| 10 mm |
|
2.21 kg / 2210.0 g
21.7 N
|
MP 12x8/4x3 / N38
| Ambient temp. (°C) | Power loss | Remaining pull | Status |
|---|---|---|---|
| 20 °C | 0.0% |
2.21 kg / 2210.0 g
21.7 N
|
OK |
| 40 °C | -2.2% |
2.16 kg / 2161.4 g
21.2 N
|
OK |
| 60 °C | -4.4% |
2.11 kg / 2112.8 g
20.7 N
|
|
| 80 °C | -6.6% |
2.06 kg / 2064.1 g
20.2 N
|
|
| 100 °C | -28.8% |
1.57 kg / 1573.5 g
15.4 N
|
MP 12x8/4x3 / N38
| Gap (mm) | Attraction (kg) (N-S) | Repulsion (kg) (N-N) |
|---|---|---|
| 0 mm |
3.09 kg / 3092 g
30.3 N
4 010 Gs
|
N/A |
| 1 mm |
2.77 kg / 2774 g
27.2 N
4 589 Gs
|
2.50 kg / 2496 g
24.5 N
~0 Gs
|
| 2 mm |
2.41 kg / 2408 g
23.6 N
4 276 Gs
|
2.17 kg / 2167 g
21.3 N
~0 Gs
|
| 3 mm |
2.03 kg / 2034 g
20.0 N
3 930 Gs
|
1.83 kg / 1831 g
18.0 N
~0 Gs
|
| 5 mm |
1.36 kg / 1362 g
13.4 N
3 216 Gs
|
1.23 kg / 1226 g
12.0 N
~0 Gs
|
| 10 mm |
0.41 kg / 412 g
4.0 N
1 770 Gs
|
0.37 kg / 371 g
3.6 N
~0 Gs
|
| 20 mm |
0.04 kg / 40 g
0.4 N
554 Gs
|
0.04 kg / 36 g
0.4 N
~0 Gs
|
| 50 mm |
0.00 kg / 0 g
0.0 N
58 Gs
|
0.00 kg / 0 g
0.0 N
~0 Gs
|
MP 12x8/4x3 / N38
| Object / Device | Limit (Gauss) / mT | Safe distance |
|---|---|---|
| Pacemaker | 5 Gs (0.5 mT) | 5.0 cm |
| Hearing aid | 10 Gs (1.0 mT) | 4.0 cm |
| Timepiece | 20 Gs (2.0 mT) | 3.0 cm |
| Phone / Smartphone | 40 Gs (4.0 mT) | 2.5 cm |
| Car key | 50 Gs (5.0 mT) | 2.5 cm |
| Payment card | 400 Gs (40.0 mT) | 1.0 cm |
| HDD hard drive | 600 Gs (60.0 mT) | 1.0 cm |
MP 12x8/4x3 / N38
| Start from (mm) | Speed (km/h) | Energy (J) | Predicted outcome |
|---|---|---|---|
| 10 mm |
31.79 km/h
(8.83 m/s)
|
0.09 J | |
| 30 mm |
54.63 km/h
(15.17 m/s)
|
0.26 J | |
| 50 mm |
70.52 km/h
(19.59 m/s)
|
0.43 J | |
| 100 mm |
99.73 km/h
(27.70 m/s)
|
0.87 J |
MP 12x8/4x3 / 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) |
MP 12x8/4x3 / N38
| Parameter | Value | SI Unit / Description |
|---|---|---|
| Magnetic Flux | 2 466 Mx | 24.7 µWb |
| Pc Coefficient | 0.32 | Low (Flat) |
MP 12x8/4x3 / N38
| Environment | Effective steel pull | Effect |
|---|---|---|
| Air (land) | 2.21 kg | Standard |
| Water (riverbed) |
2.53 kg
(+0.32 kg Buoyancy gain)
|
+14.5% |
1. Vertical hold
*Warning: On a vertical surface, the magnet holds merely approx. 20-30% of its nominal pull.
2. Steel thickness impact
*Thin metal sheet (e.g. computer case) significantly reduces the holding force.
3. Thermal stability
*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) = 0.32
The chart above illustrates the magnetic characteristics of the material within the second quadrant of the hysteresis loop. 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 |
View also proposals
Pros as well as cons of rare earth magnets.
Pros
- They do not lose power, even over around ten years – the drop in lifting capacity is only ~1% (according to tests),
- Magnets very well protect themselves against demagnetization caused by foreign field sources,
- The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
- They feature high magnetic induction at the operating surface, making them more effective,
- Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
- Thanks to freedom in designing and the ability to modify to specific needs,
- Huge importance in future technologies – they are used in computer drives, motor assemblies, advanced medical instruments, as well as industrial machines.
- Thanks to concentrated force, small magnets offer high operating force, with minimal size,
Disadvantages
- To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
- We warn that neodymium magnets can reduce their strength at high temperatures. To prevent this, we suggest our specialized [AH] magnets, which work effectively even at 230°C.
- They oxidize in a humid environment - during use outdoors we advise using waterproof magnets e.g. in rubber, plastic
- We recommend cover - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complicated forms.
- Possible danger resulting from small fragments of magnets pose a threat, if swallowed, which becomes key in the context of child safety. Additionally, tiny parts of these magnets can disrupt the diagnostic process medical in case of swallowing.
- High unit price – neodymium magnets cost more than other types of magnets (e.g. ferrite), which hinders application in large quantities
Pull force analysis
Maximum lifting capacity of the magnet – what contributes to it?
- on a base made of structural steel, effectively closing the magnetic field
- with a thickness of at least 10 mm
- characterized by even structure
- with zero gap (no paint)
- during pulling in a direction vertical to the mounting surface
- at standard ambient temperature
What influences lifting capacity in practice
- Clearance – existence of foreign body (paint, tape, air) acts as an insulator, which reduces power steeply (even by 50% at 0.5 mm).
- Pull-off angle – note that the magnet holds strongest perpendicularly. Under sliding down, the capacity drops drastically, often to levels of 20-30% of the maximum value.
- Metal thickness – thin material does not allow full use of the magnet. Part of the magnetic field penetrates through instead of converting into lifting capacity.
- Metal type – different alloys reacts the same. High carbon content worsen the interaction with the magnet.
- Surface condition – smooth surfaces ensure maximum contact, which improves field saturation. Rough surfaces reduce efficiency.
- Thermal environment – temperature increase results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.
Holding force was tested on the plate surface of 20 mm thickness, when the force acted perpendicularly, whereas under shearing force the lifting capacity is smaller. Additionally, even a small distance between the magnet’s surface and the plate reduces the lifting capacity.
Skin irritation risks
Nickel alert: The nickel-copper-nickel coating consists of nickel. If redness appears, cease handling magnets and wear gloves.
Phone sensors
An intense magnetic field interferes with the operation of compasses in smartphones and GPS navigation. Keep magnets near a smartphone to prevent damaging the sensors.
Electronic hazard
Do not bring magnets close to a wallet, laptop, or TV. The magnetic field can destroy these devices and erase data from cards.
Do not underestimate power
Handle magnets consciously. Their huge power can shock even experienced users. Be vigilant and do not underestimate their power.
Material brittleness
Protect your eyes. Magnets can fracture upon uncontrolled impact, ejecting shards into the air. Eye protection is mandatory.
Medical interference
Medical warning: Strong magnets can turn off heart devices and defibrillators. Do not approach if you have electronic implants.
Dust explosion hazard
Powder generated during machining of magnets is flammable. Do not drill into magnets without proper cooling and knowledge.
Do not give to children
Adult use only. Small elements pose a choking risk, leading to serious injuries. Store out of reach of kids and pets.
Maximum temperature
Avoid heat. NdFeB magnets are sensitive to heat. If you need resistance above 80°C, ask us about HT versions (H, SH, UH).
Hand protection
Risk of injury: The pulling power is so great that it can result in blood blisters, crushing, and broken bones. Use thick gloves.
