MW 8x20 / N38 - cylindrical magnet
cylindrical magnet
Catalog no 010475
GTIN: 5906301811138
Diameter Ø
8 mm [±0,1 mm]
Height
20 mm [±0,1 mm]
Weight
7.54 g
Magnetization Direction
→ diametrical
Load capacity
3.01 kg / 29.53 N
Magnetic Induction
607.01 mT
Coating
[NiCuNi] Nickel
4.60 ZŁ with VAT / pcs + price for transport
3.74 ZŁ net + 23% VAT / pcs
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MW 8x20 / N38 - cylindrical magnet
Specification / characteristics MW 8x20 / N38 - cylindrical magnet
| properties | values |
|---|---|
| Cat. no. | 010475 |
| GTIN | 5906301811138 |
| Production/Distribution | Dhit sp. z o.o. |
| Country of origin | Poland / China / Germany |
| Customs code | 85059029 |
| Diameter Ø | 8 mm [±0,1 mm] |
| Height | 20 mm [±0,1 mm] |
| Weight | 7.54 g |
| Magnetization Direction | → diametrical |
| Load capacity ~ ? | 3.01 kg / 29.53 N |
| Magnetic Induction ~ ? | 607.01 mT |
| 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 |
Physical analysis of the magnet - report
Presented values are the outcome of a engineering calculation. Results are based on models for the class NdFeB. Actual parameters might slightly differ from theoretical values. Treat these data as a reference point for designers.
MW 8x20 / N38
| Distance (mm) | Induction (Gauss) / mT | Pull Force (kg) | Risk Status |
|---|---|---|---|
| 0 mm |
6064 Gs
606.4 mT
|
3.01 kg / 3010.0 g
29.5 N
|
strong |
| 1 mm |
4587 Gs
458.7 mT
|
1.72 kg / 1722.0 g
16.9 N
|
weak grip |
| 2 mm |
3327 Gs
332.7 mT
|
0.91 kg / 906.1 g
8.9 N
|
weak grip |
| 5 mm |
1281 Gs
128.1 mT
|
0.13 kg / 134.3 g
1.3 N
|
weak grip |
| 10 mm |
389 Gs
38.9 mT
|
0.01 kg / 12.4 g
0.1 N
|
weak grip |
| 15 mm |
169 Gs
16.9 mT
|
0.00 kg / 2.3 g
0.0 N
|
weak grip |
| 20 mm |
90 Gs
9.0 mT
|
0.00 kg / 0.7 g
0.0 N
|
weak grip |
| 30 mm |
35 Gs
3.5 mT
|
0.00 kg / 0.1 g
0.0 N
|
weak grip |
| 50 mm |
10 Gs
1.0 mT
|
0.00 kg / 0.0 g
0.0 N
|
weak grip |
MW 8x20 / N38
| Surface type | Friction coefficient / % Mocy | Max load (kg) |
|---|---|---|
| Raw steel |
µ = 0.3
30% Nominalnej Siły
|
0.90 kg / 903.0 g
8.9 N
|
| Painted steel (standard) |
µ = 0.2
20% Nominalnej Siły
|
0.60 kg / 602.0 g
5.9 N
|
| Oily/slippery steel |
µ = 0.1
10% Nominalnej Siły
|
0.30 kg / 301.0 g
3.0 N
|
| Magnet with anti-slip rubber |
µ = 0.5
50% Nominalnej Siły
|
1.51 kg / 1505.0 g
14.8 N
|
MW 8x20 / N38
| Steel thickness (mm) | % power | Real pull force (kg) |
|---|---|---|
| 0.5 mm |
|
0.30 kg / 301.0 g
3.0 N
|
| 1 mm |
|
0.75 kg / 752.5 g
7.4 N
|
| 2 mm |
|
1.51 kg / 1505.0 g
14.8 N
|
| 5 mm |
|
3.01 kg / 3010.0 g
29.5 N
|
| 10 mm |
|
3.01 kg / 3010.0 g
29.5 N
|
MW 8x20 / N38
| Ambient temp. (°C) | Power loss | Remaining pull | Status |
|---|---|---|---|
| 20 °C | 0.0% |
3.01 kg / 3010.0 g
29.5 N
|
OK |
| 40 °C | -2.2% |
2.94 kg / 2943.8 g
28.9 N
|
OK |
| 60 °C | -4.4% |
2.88 kg / 2877.6 g
28.2 N
|
OK |
| 80 °C | -6.6% |
2.81 kg / 2811.3 g
27.6 N
|
|
| 100 °C | -28.8% |
2.14 kg / 2143.1 g
21.0 N
|
MW 8x20 / N38
| Gap (mm) | Attraction (kg) (N-S) | Repulsion (kg) (N-N) |
|---|---|---|
| 0 mm |
4.52 kg / 4515.0 g
44.3 N
|
N/A |
| 2 mm |
1.37 kg / 1365.0 g
13.4 N
|
1.27 kg / 1274.0 g
12.5 N
|
| 5 mm |
0.20 kg / 195.0 g
1.9 N
|
0.18 kg / 182.0 g
1.8 N
|
| 10 mm |
0.02 kg / 15.0 g
0.1 N
|
0.01 kg / 14.0 g
0.1 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
|
MW 8x20 / N38
| Object / Device | Limit (Gauss) / mT | Safe distance |
|---|---|---|
| Pacemaker | 5 Gs (0.5 mT) | 6.5 cm |
| Hearing aid | 10 Gs (1.0 mT) | 5.0 cm |
| Timepiece | 20 Gs (2.0 mT) | 4.0 cm |
| Phone / Smartphone | 40 Gs (4.0 mT) | 3.0 cm |
| Remote | 50 Gs (5.0 mT) | 3.0 cm |
| Payment card | 400 Gs (40.0 mT) | 1.0 cm |
| HDD hard drive | 600 Gs (60.0 mT) | 1.0 cm |
MW 8x20 / N38
| Start from (mm) | Speed (km/h) | Energy (J) | Predicted outcome |
|---|---|---|---|
| 10 mm |
20.20 km/h
(5.61 m/s)
|
0.12 J | |
| 30 mm |
34.90 km/h
(9.69 m/s)
|
0.35 J | |
| 50 mm |
45.06 km/h
(12.52 m/s)
|
0.59 J | |
| 100 mm |
63.72 km/h
(17.70 m/s)
|
1.18 J |
MW 8x20 / 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) |
MW 8x20 / N38
| Environment | Effective steel pull | Effect |
|---|---|---|
| Air (land) | 3.01 kg | Standard |
| Water (riverbed) |
3.45 kg
(+0.44 kg Buoyancy gain)
|
+14.5% |
Other proposals
Strengths as well as weaknesses of NdFeB magnets.
Apart from their strong magnetic energy, neodymium magnets have these key benefits:
- They virtually do not lose strength, because even after ten years the decline in efficiency is only ~1% (based on calculations),
- They maintain their magnetic properties even under close interference source,
- In other words, due to the reflective layer of gold, the element becomes visually attractive,
- Magnets have exceptionally strong magnetic induction on the surface,
- Due to their durability and thermal resistance, neodymium magnets are capable of operate (depending on the shape) even at high temperatures reaching 230°C or more...
- Thanks to versatility in forming and the ability to modify to unusual requirements,
- Key role in modern technologies – they are used in magnetic memories, electric drive systems, medical devices, also technologically advanced constructions.
- Compactness – despite small sizes they generate large force, making them ideal for precision applications
Disadvantages of NdFeB magnets:
- To avoid cracks under impact, we recommend using special steel holders. Such a solution protects the magnet and simultaneously increases its durability.
- When exposed to high temperature, neodymium magnets suffer a drop in power. Often, when the temperature exceeds 80°C, their power 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
- Magnets exposed to a humid environment can rust. Therefore when using outdoors, we advise using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
- Limited ability of making threads in the magnet and complicated shapes - recommended is a housing - magnetic holder.
- Potential hazard related to microscopic parts of magnets are risky, when accidentally swallowed, which becomes key in the context of child health protection. It is also worth noting that small elements of these devices are able to complicate diagnosis medical when they are in the body.
- With large orders the cost of neodymium magnets can be a barrier,
Highest magnetic holding force – what affects it?
Magnet power was defined for ideal contact conditions, assuming:
- on a base made of structural steel, effectively closing the magnetic field
- possessing a massiveness of min. 10 mm to ensure full flux closure
- with a surface perfectly flat
- without any air gap between the magnet and steel
- during detachment in a direction perpendicular to the plane
- at standard ambient temperature
Key elements affecting lifting force
In practice, the actual holding force is determined by a number of factors, ranked from crucial:
- Gap between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by veneer or unevenness) diminishes the magnet efficiency, often by half at just 0.5 mm.
- Load vector – highest force is reached only during pulling at a 90° angle. The resistance to sliding of the magnet along the surface is standardly many times smaller (approx. 1/5 of the lifting capacity).
- Steel thickness – insufficiently thick sheet does not close the flux, causing part of the flux to be escaped into the air.
- Material type – ideal substrate is high-permeability steel. Cast iron may have worse magnetic properties.
- Surface structure – the smoother and more polished the plate, the larger the contact zone and higher the lifting capacity. Unevenness acts like micro-gaps.
- Thermal conditions – NdFeB sinters have a sensitivity to temperature. At higher temperatures they are weaker, and at low temperatures they can be stronger (up to a certain limit).
* Lifting capacity was determined with the use of a polished steel plate of optimal thickness (min. 20 mm), under perpendicular detachment force, however under parallel forces the load capacity is reduced by as much as 75%. In addition, even a small distance {between} the magnet’s surface and the plate decreases the load capacity.
Safe handling of neodymium magnets
Permanent damage
Watch the temperature. Heating the magnet to high heat will ruin its properties and pulling force.
Crushing risk
Big blocks can break fingers in a fraction of a second. Never put your hand betwixt two strong magnets.
Impact on smartphones
GPS units and smartphones are highly susceptible to magnetic fields. Close proximity with a strong magnet can permanently damage the sensors in your phone.
Caution required
Use magnets with awareness. Their huge power can surprise even experienced users. Plan your moves and do not underestimate their power.
Keep away from children
NdFeB magnets are not intended for children. Swallowing multiple magnets can lead to them attracting across intestines, which poses a critical condition and necessitates immediate surgery.
Allergic reactions
A percentage of the population have a contact allergy to Ni, which is the typical protective layer for NdFeB magnets. Frequent touching might lead to skin redness. We suggest use protective gloves.
Magnets are brittle
Beware of splinters. Magnets can explode upon violent connection, ejecting shards into the air. Wear goggles.
Mechanical processing
Dust produced during grinding of magnets is combustible. Avoid drilling into magnets unless you are an expert.
Data carriers
Avoid bringing magnets close to a purse, laptop, or screen. The magnetic field can destroy these devices and erase data from cards.
Life threat
Warning for patients: Strong magnetic fields disrupt medical devices. Maintain minimum 30 cm distance or request help to work with the magnets.
Attention!
Looking for details? Read our article: Why are neodymium magnets dangerous?
