MP 12x8/4x3 / N38 - ring magnet
ring magnet
Catalog no 030395
GTIN: 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
0.28 mT / 3 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 | 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 ~ ? | 0.28 mT / 3 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 | 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 |
Engineering analysis of the product - technical parameters
The following data represent the outcome of a physical calculation. Values were calculated on algorithms for the class NdFeB. Actual conditions may differ. Use these data as a preliminary roadmap for designers.
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
|
safe |
| 2 mm |
1786 Gs
178.6 mT
|
1.20 kg / 1200.5 g
11.8 N
|
safe |
| 3 mm |
1437 Gs
143.7 mT
|
0.78 kg / 777.8 g
7.6 N
|
safe |
| 5 mm |
885 Gs
88.5 mT
|
0.29 kg / 294.7 g
2.9 N
|
safe |
| 10 mm |
277 Gs
27.7 mT
|
0.03 kg / 28.9 g
0.3 N
|
safe |
| 15 mm |
110 Gs
11.0 mT
|
0.00 kg / 4.6 g
0.0 N
|
safe |
| 20 mm |
53 Gs
5.3 mT
|
0.00 kg / 1.1 g
0.0 N
|
safe |
| 30 mm |
18 Gs
1.8 mT
|
0.00 kg / 0.1 g
0.0 N
|
safe |
| 50 mm |
4 Gs
0.4 mT
|
0.00 kg / 0.0 g
0.0 N
|
safe |
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
|
OK |
| 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 |
3.32 kg / 3315.0 g
32.5 N
|
N/A |
| 2 mm |
1.80 kg / 1800.0 g
17.7 N
|
1.68 kg / 1680.0 g
16.5 N
|
| 5 mm |
0.43 kg / 435.0 g
4.3 N
|
0.41 kg / 406.0 g
4.0 N
|
| 10 mm |
0.05 kg / 45.0 g
0.4 N
|
0.04 kg / 42.0 g
0.4 N
|
| 20 mm |
0.00 kg / 0.0 g
0.0 N
|
0.00 kg / 0.0 g
0.0 N
|
| 50 mm |
0.00 kg / 0.0 g
0.0 N
|
0.00 kg / 0.0 g
0.0 N
|
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 |
| Mobile device | 40 Gs (4.0 mT) | 2.5 cm |
| Remote | 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
| Environment | Effective steel pull | Effect |
|---|---|---|
| Air (land) | 2.21 kg | Standard |
| Water (riverbed) |
2.53 kg
(+0.32 kg Buoyancy gain)
|
+14.5% |
Other products
Pros as well as cons of neodymium magnets.
Besides their high retention, neodymium magnets are valued for these benefits:
- They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (in laboratory conditions),
- They are extremely resistant to demagnetization induced by presence of other magnetic fields,
- The use of an metallic layer of noble metals (nickel, gold, silver) causes the element to be more visually attractive,
- Magnets are characterized by maximum magnetic induction on the active area,
- Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the form) even at a temperature of 230°C or more...
- Thanks to versatility in constructing and the capacity to customize to individual projects,
- Universal use in modern industrial fields – they are commonly used in computer drives, drive modules, precision medical tools, as well as modern systems.
- Thanks to efficiency per cm³, small magnets offer high operating force, with minimal size,
Problematic aspects of neodymium magnets: application proposals
- To avoid cracks upon strong impacts, we suggest using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
- NdFeB magnets demagnetize when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening 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
- When exposed to humidity, magnets start to rust. For applications outside, it is recommended to use protective magnets, such as magnets in rubber or plastics, which secure oxidation as well as corrosion.
- Due to limitations in producing nuts and complicated shapes in magnets, we recommend using a housing - magnetic mount.
- Health risk to health – tiny shards of magnets can be dangerous, in case of ingestion, which gains importance in the aspect of protecting the youngest. Furthermore, small components of these magnets can be problematic in diagnostics medical after entering the body.
- Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications
Breakaway strength of the magnet in ideal conditions – what contributes to it?
The lifting capacity listed is a theoretical maximum value conducted under specific, ideal conditions:
- on a base made of mild steel, optimally conducting the magnetic field
- possessing a thickness of at least 10 mm to avoid saturation
- with a plane cleaned and smooth
- without the slightest air gap between the magnet and steel
- during pulling in a direction vertical to the plane
- at room temperature
Practical aspects of lifting capacity – factors
It is worth knowing that the working load may be lower influenced by the following factors, starting with the most relevant:
- Air gap (between the magnet and the plate), because even a very small distance (e.g. 0.5 mm) can cause a drastic drop in force by up to 50% (this also applies to paint, corrosion or debris).
- Force direction – catalog parameter refers to detachment vertically. When slipping, the magnet holds significantly lower power (typically approx. 20-30% of maximum force).
- Metal thickness – thin material does not allow full use of the magnet. Magnetic flux passes through the material instead of converting into lifting capacity.
- Steel grade – the best choice is high-permeability steel. Hardened steels may generate lower lifting capacity.
- Surface structure – the smoother and more polished the surface, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
- Thermal environment – heating the magnet results in weakening of force. It is worth remembering the thermal limit for a given model.
* Lifting capacity was assessed with the use of a smooth steel plate of optimal thickness (min. 20 mm), under vertically applied force, in contrast under shearing force the lifting capacity is smaller. In addition, even a slight gap {between} the magnet’s surface and the plate reduces the load capacity.
H&S for magnets
Risk of cracking
NdFeB magnets are sintered ceramics, meaning they are very brittle. Collision of two magnets leads to them shattering into small pieces.
Finger safety
Big blocks can break fingers in a fraction of a second. Do not place your hand betwixt two strong magnets.
Danger to pacemakers
Warning for patients: Strong magnetic fields disrupt medical devices. Maintain minimum 30 cm distance or ask another person to handle the magnets.
Precision electronics
A powerful magnetic field negatively affects the functioning of magnetometers in phones and navigation systems. Keep magnets near a smartphone to avoid breaking the sensors.
Warning for allergy sufferers
Studies show that the nickel plating (the usual finish) is a strong allergen. For allergy sufferers, prevent touching magnets with bare hands or opt for versions in plastic housing.
Caution required
Before starting, read the rules. Sudden snapping can destroy the magnet or hurt your hand. Be predictive.
Choking Hazard
These products are not toys. Accidental ingestion of several magnets can lead to them connecting inside the digestive tract, which constitutes a critical condition and requires immediate surgery.
Operating temperature
Control the heat. Heating the magnet to high heat will ruin its properties and strength.
Keep away from computers
Equipment safety: Strong magnets can ruin data carriers and delicate electronics (heart implants, hearing aids, timepieces).
Combustion hazard
Powder generated during cutting of magnets is flammable. Do not drill into magnets without proper cooling and knowledge.
Attention!
Details about hazards in the article: Magnet Safety Guide.
