Neodymiums – complete shape selection

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Magnet fishing sets (hobbyists)

Begin your hobby related to seabed exploration! Our specialized grips (F200, F400) provide safety guarantee and huge lifting capacity. Stainless steel construction and strong lines are reliable in any water.

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Reliable threaded grips

Professional solutions for mounting non-invasive. Threaded grips (external or internal) guarantee quick improvement of work on warehouses. Perfect for mounting lighting, sensors and banners.

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MP 20x10x5 / N38 - ring magnet

ring magnet

Catalog no 030184

GTIN/EAN: 5906301812012

5.00

Diameter

20 mm [±0,1 mm]

internal diameter Ø

10 mm [±0,1 mm]

Height

5 mm [±0,1 mm]

Weight

8.84 g

Magnetization Direction

↑ axial

Load capacity

5.20 kg / 50.97 N

Magnetic Induction

277.16 mT / 2772 Gs

Coating

[NiCuNi] Nickel

4.50 with VAT / pcs + price for transport

3.66 ZŁ net + 23% VAT / pcs

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Physical properties - MP 20x10x5 / N38 - ring magnet

Specification / characteristics - MP 20x10x5 / N38 - ring magnet

properties
properties values
Cat. no. 030184
GTIN/EAN 5906301812012
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 10 mm [±0,1 mm]
Height 5 mm [±0,1 mm]
Weight 8.84 g
Magnetization Direction ↑ axial
Load capacity ~ ? 5.20 kg / 50.97 N
Magnetic Induction ~ ? 277.16 mT / 2772 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 20x10x5 / 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 analysis of the product - technical parameters

Presented information represent the result of a physical simulation. Values are based on algorithms for the material Nd2Fe14B. Real-world performance may differ from theoretical values. Please consider these data as a supplementary guide when designing systems.

Table 1: Static pull force (pull vs distance) - interaction chart
MP 20x10x5 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 5917 Gs
591.7 mT
5.20 kg / 11.46 lbs
5200.0 g / 51.0 N
strong
1 mm 5321 Gs
532.1 mT
4.21 kg / 9.27 lbs
4205.9 g / 41.3 N
strong
2 mm 4736 Gs
473.6 mT
3.33 kg / 7.35 lbs
3332.2 g / 32.7 N
strong
3 mm 4184 Gs
418.4 mT
2.60 kg / 5.73 lbs
2600.0 g / 25.5 N
strong
5 mm 3216 Gs
321.6 mT
1.54 kg / 3.39 lbs
1536.2 g / 15.1 N
low risk
10 mm 1650 Gs
165.0 mT
0.40 kg / 0.89 lbs
404.2 g / 4.0 N
low risk
15 mm 907 Gs
90.7 mT
0.12 kg / 0.27 lbs
122.3 g / 1.2 N
low risk
20 mm 544 Gs
54.4 mT
0.04 kg / 0.10 lbs
44.0 g / 0.4 N
low risk
30 mm 240 Gs
24.0 mT
0.01 kg / 0.02 lbs
8.5 g / 0.1 N
low risk
50 mm 75 Gs
7.5 mT
0.00 kg / 0.00 lbs
0.8 g / 0.0 N
low risk

Table 2: Sliding force (wall)
MP 20x10x5 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 1.04 kg / 2.29 lbs
1040.0 g / 10.2 N
1 mm Stal (~0.2) 0.84 kg / 1.86 lbs
842.0 g / 8.3 N
2 mm Stal (~0.2) 0.67 kg / 1.47 lbs
666.0 g / 6.5 N
3 mm Stal (~0.2) 0.52 kg / 1.15 lbs
520.0 g / 5.1 N
5 mm Stal (~0.2) 0.31 kg / 0.68 lbs
308.0 g / 3.0 N
10 mm Stal (~0.2) 0.08 kg / 0.18 lbs
80.0 g / 0.8 N
15 mm Stal (~0.2) 0.02 kg / 0.05 lbs
24.0 g / 0.2 N
20 mm Stal (~0.2) 0.01 kg / 0.02 lbs
8.0 g / 0.1 N
30 mm Stal (~0.2) 0.00 kg / 0.00 lbs
2.0 g / 0.0 N
50 mm Stal (~0.2) 0.00 kg / 0.00 lbs
0.0 g / 0.0 N

Table 3: Vertical assembly (sliding) - behavior on slippery surfaces
MP 20x10x5 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
1.56 kg / 3.44 lbs
1560.0 g / 15.3 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
1.04 kg / 2.29 lbs
1040.0 g / 10.2 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
0.52 kg / 1.15 lbs
520.0 g / 5.1 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
2.60 kg / 5.73 lbs
2600.0 g / 25.5 N

Table 4: Material efficiency (substrate influence) - power losses
MP 20x10x5 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
10%
0.52 kg / 1.15 lbs
520.0 g / 5.1 N
1 mm
25%
1.30 kg / 2.87 lbs
1300.0 g / 12.8 N
2 mm
50%
2.60 kg / 5.73 lbs
2600.0 g / 25.5 N
3 mm
75%
3.90 kg / 8.60 lbs
3900.0 g / 38.3 N
5 mm
100%
5.20 kg / 11.46 lbs
5200.0 g / 51.0 N
10 mm
100%
5.20 kg / 11.46 lbs
5200.0 g / 51.0 N
11 mm
100%
5.20 kg / 11.46 lbs
5200.0 g / 51.0 N
12 mm
100%
5.20 kg / 11.46 lbs
5200.0 g / 51.0 N

Table 5: Working in heat (stability) - power drop
MP 20x10x5 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 5.20 kg / 11.46 lbs
5200.0 g / 51.0 N
OK
40 °C -2.2% 5.09 kg / 11.21 lbs
5085.6 g / 49.9 N
OK
60 °C -4.4% 4.97 kg / 10.96 lbs
4971.2 g / 48.8 N
OK
80 °C -6.6% 4.86 kg / 10.71 lbs
4856.8 g / 47.6 N
100 °C -28.8% 3.70 kg / 8.16 lbs
3702.4 g / 36.3 N

Table 6: Two magnets (attraction) - field range
MP 20x10x5 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Sliding Force (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 54.03 kg / 119.11 lbs
6 121 Gs
8.10 kg / 17.87 lbs
8104 g / 79.5 N
N/A
1 mm 48.76 kg / 107.50 lbs
11 242 Gs
7.31 kg / 16.13 lbs
7314 g / 71.8 N
43.89 kg / 96.75 lbs
~0 Gs
2 mm 43.70 kg / 96.34 lbs
10 642 Gs
6.55 kg / 14.45 lbs
6555 g / 64.3 N
39.33 kg / 86.71 lbs
~0 Gs
3 mm 38.98 kg / 85.94 lbs
10 051 Gs
5.85 kg / 12.89 lbs
5847 g / 57.4 N
35.08 kg / 77.34 lbs
~0 Gs
5 mm 30.63 kg / 67.54 lbs
8 910 Gs
4.60 kg / 10.13 lbs
4595 g / 45.1 N
27.57 kg / 60.78 lbs
~0 Gs
10 mm 15.96 kg / 35.19 lbs
6 432 Gs
2.39 kg / 5.28 lbs
2394 g / 23.5 N
14.36 kg / 31.67 lbs
~0 Gs
20 mm 4.20 kg / 9.26 lbs
3 299 Gs
0.63 kg / 1.39 lbs
630 g / 6.2 N
3.78 kg / 8.33 lbs
~0 Gs
50 mm 0.19 kg / 0.42 lbs
702 Gs
0.03 kg / 0.06 lbs
29 g / 0.3 N
0.17 kg / 0.38 lbs
~0 Gs
60 mm 0.09 kg / 0.20 lbs
480 Gs
0.01 kg / 0.03 lbs
13 g / 0.1 N
0.08 kg / 0.18 lbs
~0 Gs
70 mm 0.05 kg / 0.10 lbs
342 Gs
0.01 kg / 0.01 lbs
7 g / 0.1 N
0.04 kg / 0.09 lbs
~0 Gs
80 mm 0.02 kg / 0.05 lbs
253 Gs
0.00 kg / 0.01 lbs
4 g / 0.0 N
0.02 kg / 0.05 lbs
~0 Gs
90 mm 0.01 kg / 0.03 lbs
193 Gs
0.00 kg / 0.00 lbs
2 g / 0.0 N
0.01 kg / 0.03 lbs
~0 Gs
100 mm 0.01 kg / 0.02 lbs
150 Gs
0.00 kg / 0.00 lbs
1 g / 0.0 N
0.00 kg / 0.00 lbs
~0 Gs

Table 7: Hazards (implants) - warnings
MP 20x10x5 / 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
Timepiece 20 Gs (2.0 mT) 9.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 6.5 cm
Car key 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: Collisions (kinetic energy) - collision effects
MP 20x10x5 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 25.62 km/h
(7.12 m/s)
0.22 J
30 mm 42.41 km/h
(11.78 m/s)
0.61 J
50 mm 54.70 km/h
(15.19 m/s)
1.02 J
100 mm 77.35 km/h
(21.49 m/s)
2.04 J

Table 9: Corrosion resistance
MP 20x10x5 / 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 20x10x5 / N38

Parameter Value SI Unit / Description
Magnetic Flux 16 116 Mx 161.2 µWb
Pc Coefficient 1.13 High (Stable)

Table 11: Underwater work (magnet fishing)
MP 20x10x5 / N38

Environment Effective steel pull Effect
Air (land) 5.20 kg Standard
Water (riverbed) 5.95 kg
(+0.75 kg buoyancy gain)
+14.5%
Rust risk: Remember to wipe the magnet thoroughly after removing it from water and apply a protective layer (e.g., oil) to avoid corrosion.
1. Shear force

*Note: On a vertical wall, the magnet retains merely approx. 20-30% of its nominal pull.

2. Steel thickness impact

*Thin metal sheet (e.g. computer case) severely weakens the holding force.

3. Power loss vs temp

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

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

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 1.13

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
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%
Ecology and recycling (GPSR)
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: 030184-2026
Measurement Calculator
Pulling force

Magnetic Induction

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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. This product with a force of 5.20 kg works great as a cabinet closure, speaker holder, or spacer element in devices.
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 excessive force will cause the ring to crack. It's a good idea to use a rubber spacer under the screw head, which will cushion the stresses. Remember: cracking during assembly results from material properties, not a product defect.
These magnets are coated with standard Ni-Cu-Ni plating, which protects them in indoor conditions, but is not sufficient for rain. In the place of the mounting hole, the coating is thinner and can be damaged when tightening the screw, which will become a corrosion focus. This product is dedicated for indoor use. For outdoor applications, we recommend choosing magnets in hermetic housing or additional protection with varnish.
The inner hole diameter determines the maximum size of the mounting element. If the magnet does not have a chamfer (cone), we recommend using a screw with a flat or cylindrical head, or possibly using a washer. Aesthetic mounting requires selecting the appropriate head size.
It is a magnetic ring with a diameter of 20 mm and thickness 5 mm. The key parameter here is the holding force amounting to approximately 5.20 kg (force ~50.97 N). The mounting hole diameter is precisely 10 mm.
The poles are located on the planes with holes, not on the sides of the ring. If you want two such magnets screwed with cones facing each other (faces) to attract, you must connect them with opposite poles (N to S). We do not offer paired sets with marked poles in this category, but they are easy to match manually.

Advantages and disadvantages of rare earth magnets.

Benefits

Besides their high retention, neodymium magnets are valued for these benefits:
  • They have unchanged lifting capacity, and over nearly ten years their performance decreases symbolically – ~1% (in testing),
  • They maintain their magnetic properties even under close interference source,
  • A magnet with a smooth nickel surface is more attractive,
  • The surface of neodymium magnets generates a strong magnetic field – this is a key feature,
  • Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their form) at temperatures up to 230°C and above...
  • Thanks to flexibility in constructing and the ability to modify to client solutions,
  • Versatile presence in modern technologies – they find application in HDD drives, electric drive systems, medical devices, as well as multitasking production systems.
  • Compactness – despite small sizes they provide effective action, making them ideal for precision applications

Disadvantages

What to avoid - cons of neodymium magnets: tips and applications.
  • Susceptibility to cracking is one of their disadvantages. Upon intense impact they can break. We advise keeping them in a special holder, which not only secures them against impacts but also raises their durability
  • When exposed to high temperature, neodymium magnets experience a drop in strength. Often, when the temperature exceeds 80°C, their strength 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 during using outdoors, we recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
  • We recommend a housing - magnetic mount, due to difficulties in producing nuts inside the magnet and complicated forms.
  • Possible danger to health – tiny shards of magnets pose a threat, if swallowed, which is particularly important in the aspect of protecting the youngest. Furthermore, small elements of these products 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

Pull force analysis

Optimal lifting capacity of a neodymium magnetwhat it depends on?

The declared magnet strength concerns the peak performance, obtained under laboratory conditions, meaning:
  • on a block made of mild steel, perfectly concentrating the magnetic flux
  • possessing a thickness of at least 10 mm to avoid saturation
  • with a surface perfectly flat
  • with direct contact (without impurities)
  • during pulling in a direction vertical to the plane
  • in neutral thermal conditions

Lifting capacity in real conditions – factors

It is worth knowing that the working load will differ depending on the following factors, in order of importance:
  • Gap between surfaces – every millimeter of distance (caused e.g. by varnish or dirt) significantly weakens the pulling force, often by half at just 0.5 mm.
  • Load vector – highest force is available only during perpendicular pulling. The shear force of the magnet along the plate is typically several times lower (approx. 1/5 of the lifting capacity).
  • Metal thickness – the thinner the sheet, the weaker the hold. Part of the magnetic field penetrates through instead of generating force.
  • Material type – ideal substrate is high-permeability steel. Stainless steels may attract less.
  • Plate texture – ground elements guarantee perfect abutment, which improves force. Rough surfaces weaken the grip.
  • Thermal environment – temperature increase causes a temporary drop of force. Check the maximum operating temperature for a given model.

Lifting capacity was measured by applying a steel plate with a smooth surface of optimal thickness (min. 20 mm), under perpendicular pulling force, whereas under attempts to slide the magnet the holding force is lower. Additionally, even a minimal clearance between the magnet and the plate decreases the holding force.

Warnings
Keep away from electronics

A strong magnetic field negatively affects the operation of compasses in phones and GPS navigation. Keep magnets near a device to avoid breaking the sensors.

Product not for children

Absolutely store magnets away from children. Risk of swallowing is high, and the consequences of magnets clamping inside the body are tragic.

Machining danger

Powder created during cutting of magnets is self-igniting. Avoid drilling into magnets without proper cooling and knowledge.

Do not underestimate power

Handle magnets with awareness. Their powerful strength can surprise even experienced users. Be vigilant and respect their power.

Keep away from computers

Very strong magnetic fields can erase data on credit cards, hard drives, and other magnetic media. Stay away of at least 10 cm.

Operating temperature

Control the heat. Heating the magnet above 80 degrees Celsius will permanently weaken its magnetic structure and strength.

Life threat

Medical warning: Neodymium magnets can deactivate pacemakers and defibrillators. Stay away if you have electronic implants.

Serious injuries

Risk of injury: The attraction force is so immense that it can result in blood blisters, crushing, and broken bones. Protective gloves are recommended.

Fragile material

Watch out for shards. Magnets can fracture upon uncontrolled impact, launching shards into the air. We recommend safety glasses.

Metal Allergy

Allergy Notice: The Ni-Cu-Ni coating contains nickel. If skin irritation occurs, cease handling magnets and use protective gear.

Security! Looking for details? Check our post: Are neodymium magnets dangerous?
Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98