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MP 20x5x27 / N38 - ring magnet

ring magnet

Catalog no 030185

GTIN/EAN: 5906301812029

5.00

Diameter

20 mm [±0,1 mm]

internal diameter Ø

5 mm [±0,1 mm]

Height

27 mm [±0,1 mm]

Weight

59.64 g

Magnetization Direction

↑ axial

Load capacity

10.36 kg / 101.60 N

Magnetic Induction

581.04 mT / 5810 Gs

Coating

[NiCuNi] Nickel

33.00 with VAT / pcs + price for transport

26.83 ZŁ net + 23% VAT / pcs

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Technical specification - MP 20x5x27 / N38 - ring magnet

Specification / characteristics - MP 20x5x27 / N38 - ring magnet

properties
properties values
Cat. no. 030185
GTIN/EAN 5906301812029
Production/Distribution Dhit sp. z o.o.
ul. Zielona 14 05-850 Ożarów Mazowiecki PL
Country of origin Poland / China / Germany
Customs code 85059029
Diameter 20 mm [±0,1 mm]
internal diameter Ø 5 mm [±0,1 mm]
Height 27 mm [±0,1 mm]
Weight 59.64 g
Magnetization Direction ↑ axial
Load capacity ~ ? 10.36 kg / 101.60 N
Magnetic Induction ~ ? 581.04 mT / 5810 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 20x5x27 / N38 - ring magnet
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

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 modeling of the product - data

Presented values are the outcome of a mathematical simulation. Values rely on algorithms for the material Nd2Fe14B. Actual conditions might slightly differ. Use these calculations as a supplementary guide when designing systems.

Table 1: Static pull force (pull vs gap) - power drop
MP 20x5x27 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg) Risk Status
0 mm 5716 Gs
571.6 mT
10.36 kg / 10360.0 g
101.6 N
critical level
1 mm 5288 Gs
528.8 mT
8.87 kg / 8865.5 g
87.0 N
strong
2 mm 4861 Gs
486.1 mT
7.49 kg / 7491.0 g
73.5 N
strong
3 mm 4446 Gs
444.6 mT
6.27 kg / 6267.5 g
61.5 N
strong
5 mm 3677 Gs
367.7 mT
4.29 kg / 4285.9 g
42.0 N
strong
10 mm 2216 Gs
221.6 mT
1.56 kg / 1557.1 g
15.3 N
safe
15 mm 1354 Gs
135.4 mT
0.58 kg / 580.9 g
5.7 N
safe
20 mm 864 Gs
86.4 mT
0.24 kg / 236.9 g
2.3 N
safe
30 mm 405 Gs
40.5 mT
0.05 kg / 52.1 g
0.5 N
safe
50 mm 133 Gs
13.3 mT
0.01 kg / 5.6 g
0.1 N
safe

Table 2: Slippage force (vertical surface)
MP 20x5x27 / N38

Distance (mm) Friction coefficient Pull Force (kg)
0 mm Stal (~0.2) 2.07 kg / 2072.0 g
20.3 N
1 mm Stal (~0.2) 1.77 kg / 1774.0 g
17.4 N
2 mm Stal (~0.2) 1.50 kg / 1498.0 g
14.7 N
3 mm Stal (~0.2) 1.25 kg / 1254.0 g
12.3 N
5 mm Stal (~0.2) 0.86 kg / 858.0 g
8.4 N
10 mm Stal (~0.2) 0.31 kg / 312.0 g
3.1 N
15 mm Stal (~0.2) 0.12 kg / 116.0 g
1.1 N
20 mm Stal (~0.2) 0.05 kg / 48.0 g
0.5 N
30 mm Stal (~0.2) 0.01 kg / 10.0 g
0.1 N
50 mm Stal (~0.2) 0.00 kg / 2.0 g
0.0 N

Table 3: Wall mounting (sliding) - vertical pull
MP 20x5x27 / N38

Surface type Friction coefficient / % Mocy Max load (kg)
Raw steel
µ = 0.3 30% Nominalnej Siły
3.11 kg / 3108.0 g
30.5 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
2.07 kg / 2072.0 g
20.3 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
1.04 kg / 1036.0 g
10.2 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
5.18 kg / 5180.0 g
50.8 N

Table 4: Material efficiency (saturation) - sheet metal selection
MP 20x5x27 / N38

Steel thickness (mm) % power Real pull force (kg)
0.5 mm
5%
0.52 kg / 518.0 g
5.1 N
1 mm
13%
1.30 kg / 1295.0 g
12.7 N
2 mm
25%
2.59 kg / 2590.0 g
25.4 N
5 mm
63%
6.48 kg / 6475.0 g
63.5 N
10 mm
100%
10.36 kg / 10360.0 g
101.6 N

Table 5: Thermal resistance (material behavior) - power drop
MP 20x5x27 / N38

Ambient temp. (°C) Power loss Remaining pull Status
20 °C 0.0% 10.36 kg / 10360.0 g
101.6 N
OK
40 °C -2.2% 10.13 kg / 10132.1 g
99.4 N
OK
60 °C -4.4% 9.90 kg / 9904.2 g
97.2 N
OK
80 °C -6.6% 9.68 kg / 9676.2 g
94.9 N
100 °C -28.8% 7.38 kg / 7376.3 g
72.4 N

Table 6: Magnet-Magnet interaction (repulsion) - field collision
MP 20x5x27 / N38

Gap (mm) Attraction (kg) (N-S) Repulsion (kg) (N-N)
0 mm 44.24 kg / 44243 g
434.0 N
6 064 Gs
N/A
1 mm 41.02 kg / 41018 g
402.4 N
11 008 Gs
36.92 kg / 36917 g
362.2 N
~0 Gs
2 mm 37.86 kg / 37860 g
371.4 N
10 576 Gs
34.07 kg / 34074 g
334.3 N
~0 Gs
3 mm 34.85 kg / 34848 g
341.9 N
10 146 Gs
31.36 kg / 31363 g
307.7 N
~0 Gs
5 mm 29.30 kg / 29295 g
287.4 N
9 303 Gs
26.37 kg / 26366 g
258.6 N
~0 Gs
10 mm 18.30 kg / 18303 g
179.6 N
7 353 Gs
16.47 kg / 16473 g
161.6 N
~0 Gs
20 mm 6.65 kg / 6650 g
65.2 N
4 432 Gs
5.98 kg / 5985 g
58.7 N
~0 Gs
50 mm 0.45 kg / 455 g
4.5 N
1 159 Gs
0.41 kg / 409 g
4.0 N
~0 Gs

Table 7: Hazards (electronics) - warnings
MP 20x5x27 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 18.0 cm
Hearing aid 10 Gs (1.0 mT) 14.0 cm
Timepiece 20 Gs (2.0 mT) 11.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 8.5 cm
Remote 50 Gs (5.0 mT) 7.5 cm
Payment card 400 Gs (40.0 mT) 3.5 cm
HDD hard drive 600 Gs (60.0 mT) 2.5 cm

Table 8: Collisions (cracking risk) - warning
MP 20x5x27 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 14.49 km/h
(4.02 m/s)
0.48 J
30 mm 23.09 km/h
(6.42 m/s)
1.23 J
50 mm 29.73 km/h
(8.26 m/s)
2.03 J
100 mm 42.03 km/h
(11.68 m/s)
4.07 J

Table 9: Anti-corrosion coating durability
MP 20x5x27 / 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 20x5x27 / N38

Parameter Value SI Unit / Description
Magnetic Flux 14 314 Mx 143.1 µWb
Pc Coefficient 1.16 High (Stable)

Table 11: Underwater work (magnet fishing)
MP 20x5x27 / N38

Environment Effective steel pull Effect
Air (land) 10.36 kg Standard
Water (riverbed) 11.86 kg
(+1.50 kg Buoyancy gain)
+14.5%
Warning: This magnet has a standard nickel coating. After use in water, it must be dried and maintained immediately, otherwise it will rust!
1. Vertical hold

*Caution: On a vertical wall, the magnet retains only ~20% of its perpendicular strength.

2. Plate thickness effect

*Thin metal sheet (e.g. computer case) drastically limits the holding force.

3. Power loss vs temp

*For N38 material, the max working temp is 80°C.

4. Demagnetization curve and operating point (B-H)

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 1.16

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.

Technical specification and ecology
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%
Sustainability
recyclability (EoL) 100%
recycled raw materials ~10% (pre-cons)
carbon footprint low / zredukowany
waste code (EWC) 16 02 16
Safety card (GPSR)
responsible entity
Dhit sp. z o.o.
ul. Kościuszki 6A, 05-850 Ożarów Mazowiecki
tel: +48 22 499 98 98 | e-mail: bok@dhit.pl
batch number/type
id: 030185-2025
Quick Unit Converter
Force (pull)

Magnetic Induction

Other products

It is ideally suited for places where solid attachment of the magnet to the substrate is required without the risk of detachment. Thanks to the hole (often for a screw), this model enables quick installation to wood, wall, plastic, or metal. It is also often used in advertising for fixing signs and in workshops for organizing tools.
This material behaves more like porcelain than steel, so it doesn't forgive mistakes during mounting. When tightening the screw, you must maintain caution. We recommend tightening manually with a screwdriver, not an impact driver, because too much pressure will cause the ring to crack. The flat screw head should evenly press the magnet. Remember: cracking during assembly results from material properties, not a product defect.
Moisture can penetrate micro-cracks in the coating and cause oxidation of the magnet. Damage to the protective layer during assembly is the most common cause of rusting. If you must use it outside, paint it with anti-corrosion paint after mounting.
A screw or bolt with a thread diameter smaller than 5 mm fits this model. For magnets with a straight hole, a conical head can act like a wedge and burst the magnet. Aesthetic mounting requires selecting the appropriate head size.
The presented product is a ring magnet with dimensions Ø20 mm (outer diameter) and height 27 mm. The key parameter here is the holding force amounting to approximately 10.36 kg (force ~101.60 N). The product has a [NiCuNi] coating and is made of NdFeB material. Inner hole dimension: 5 mm.
These magnets are magnetized axially (through the thickness), which means one flat side is the N pole and the other is S. In the case of connecting two rings, make sure one is turned the right way. We do not offer paired sets with marked poles in this category, but they are easy to match manually.

Pros as well as cons of neodymium magnets.

Advantages

Apart from their strong power, neodymium magnets have these key benefits:
  • They retain full power for nearly 10 years – the drop is just ~1% (in theory),
  • They possess excellent resistance to magnetic field loss as a result of external fields,
  • The use of an elegant finish of noble metals (nickel, gold, silver) causes the element to look better,
  • The surface of neodymium magnets generates a strong magnetic field – this is one of their assets,
  • Through (appropriate) combination of ingredients, they can achieve high thermal resistance, enabling operation at temperatures reaching 230°C and above...
  • Considering the possibility of free shaping and adaptation to specialized projects, neodymium magnets can be created in a wide range of shapes and sizes, which increases their versatility,
  • Key role in innovative solutions – they serve a role in mass storage devices, brushless drives, advanced medical instruments, as well as multitasking production systems.
  • Compactness – despite small sizes they offer powerful magnetic field, making them ideal for precision applications

Limitations

Disadvantages of neodymium magnets:
  • They are prone to damage upon too strong impacts. To avoid cracks, it is worth securing magnets in special housings. Such protection not only shields the magnet but also improves its resistance to damage
  • 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.
  • They rust in a humid environment. For use outdoors we recommend using waterproof magnets e.g. in rubber, plastic
  • Due to limitations in realizing threads and complex forms in magnets, we propose using casing - magnetic mount.
  • Possible danger to health – tiny shards of magnets pose a threat, when accidentally swallowed, which becomes key in the context of child safety. It is also worth noting that small components of these devices are able to complicate diagnosis medical after entering the body.
  • Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Holding force characteristics

Maximum holding power of the magnet – what contributes to it?

Breakaway force was determined for ideal contact conditions, taking into account:
  • using a base made of high-permeability steel, acting as a circuit closing element
  • with a cross-section no less than 10 mm
  • characterized by even structure
  • with total lack of distance (without coatings)
  • during pulling in a direction vertical to the plane
  • at room temperature

Determinants of practical lifting force of a magnet

In real-world applications, the actual holding force results from many variables, presented from most significant:
  • Space between magnet and steel – even a fraction of a millimeter of separation (caused e.g. by varnish or unevenness) significantly weakens the pulling force, often by half at just 0.5 mm.
  • Angle of force application – highest force is available only during perpendicular pulling. The resistance to sliding of the magnet along the surface is typically several times smaller (approx. 1/5 of the lifting capacity).
  • Steel thickness – too thin plate does not accept the full field, causing part of the flux to be wasted into the air.
  • Steel type – low-carbon steel attracts best. Higher carbon content reduce magnetic properties and lifting capacity.
  • Surface structure – the smoother and more polished the surface, the larger the contact zone and stronger the hold. Unevenness creates an air distance.
  • Thermal environment – heating the magnet results in weakening of induction. It is worth remembering the maximum operating temperature for a given model.

Lifting capacity testing was performed on plates with a smooth surface of optimal thickness, under a perpendicular pulling force, however under attempts to slide the magnet the load capacity is reduced by as much as fivefold. Additionally, even a slight gap between the magnet’s surface and the plate lowers the lifting capacity.

Precautions when working with NdFeB magnets
Do not underestimate power

Exercise caution. Neodymium magnets act from a long distance and connect with huge force, often quicker than you can react.

Choking Hazard

Neodymium magnets are not suitable for play. Swallowing multiple magnets can lead to them connecting inside the digestive tract, which constitutes a direct threat to life and requires immediate surgery.

Metal Allergy

Studies show that nickel (standard magnet coating) is a common allergen. If your skin reacts to metals, refrain from touching magnets with bare hands or choose encased magnets.

Magnetic media

Do not bring magnets near a purse, laptop, or TV. The magnetism can irreversibly ruin these devices and wipe information from cards.

Keep away from electronics

Note: rare earth magnets produce a field that confuses sensitive sensors. Keep a safe distance from your phone, tablet, and navigation systems.

Crushing risk

Pinching hazard: The attraction force is so immense that it can result in blood blisters, crushing, and even bone fractures. Protective gloves are recommended.

Machining danger

Mechanical processing of NdFeB material poses a fire hazard. Neodymium dust oxidizes rapidly with oxygen and is difficult to extinguish.

Protective goggles

Despite metallic appearance, the material is delicate and not impact-resistant. Avoid impacts, as the magnet may crumble into sharp, dangerous pieces.

Warning for heart patients

Individuals with a heart stimulator must maintain an safe separation from magnets. The magnetic field can stop the operation of the implant.

Demagnetization risk

Do not overheat. Neodymium magnets are sensitive to heat. If you require operation above 80°C, look for HT versions (H, SH, UH).

Safety First! Want to know more? Read our article: Are neodymium magnets dangerous?
Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98