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MP 10x7/3.5x3 / N38 - ring magnet

ring magnet

Catalog no 030180

GTIN/EAN: 5906301811978

5.00
Load capacity 1.88 kg / 18.44 N Magnetic Induction 318.70 mT / 3187 Gs
Diameter
10 mm [±0,1 mm]
internal diameter Ø
7/3.5 mm [±0,1 mm]
Height
3 mm [±0,1 mm]
Weight
1.55 g
Magnetization Direction
↑ axial
Coating
[NiCuNi] Nickel

How we measure these parameters — certificates and measurements

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Frequently asked questions

What is the hole in a ring magnet for?
For mounting on a screw or a shaft. The bore may be cylindrical or countersunk for a screw head. The hole removes magnet volume, so a ring holds less than a disc of the same outside diameter.
What is the polarisation?
Axial as standard — poles on the flat faces of the ring. Diametrical polarisation is made to order.
What sizes are available?
Outside diameter from 5 to 62 mm from stock. To order up to 200 mm outside diameter, 180 mm bore and 40 mm height, with a lead time of 25–35 days.

Engineering report for this magnet

Full PDF analysis: pull and shear force, effect of distance, temperature and plate thickness, safety distances and the demagnetization curve.

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Call us now +48 888 99 98 98 alternatively let us know using contact form the contact section.
Specifications and structure of a neodymium magnet can be estimated using our power calculator.

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Detailed specification - MP 10x7/3.5x3 / N38 - ring magnet

Specification / characteristics - MP 10x7/3.5x3 / N38 - ring magnet

properties
properties values
Cat. no. 030180
GTIN/EAN 5906301811978
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 10 mm [±0,1 mm]
internal diameter Ø 7/3.5 mm [±0,1 mm]
Height 3 mm [±0,1 mm]
Weight 1.55 g
Magnetization Direction ↑ axial
Load capacity ~ ? 1.88 kg / 18.44 N
Magnetic Induction ~ ? 318.70 mT / 3187 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 10x7/3.5x3 / N38 - ring magnet
properties values units
Remanence Br ? 12.2-12.6 kGs
Remanence Br ? 1220-1260 mT
Coercivity bHc ? 10.8-11.5 kOe
Coercivity bHc ? 860-915 kA/m
Intrinsic coercivity iHc ≥ 12 kOe
Intrinsic coercivity iHc ≥ 955 kA/m
Energy product BHmax ? 36-38 BH max MGOe
Energy product BHmax ? 287-303 BH max KJ/m
Maximum working 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 310 °C
Curie Temperature TF 590 °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

Engineering simulation of the assembly - technical parameters

These data represent the result of a physical analysis. Results were calculated on models for the class Nd2Fe14B. Operational performance might slightly differ. Use these data as a preliminary roadmap when designing systems.

Table 1: Static pull force (pull vs distance) - interaction chart
MP 10x7/3.5x3 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 2813 Gs
281.3 mT
1.88 kg / 4.14 LBS
1880.0 g / 18.4 N
low risk
1 mm 2373 Gs
237.3 mT
1.34 kg / 2.95 LBS
1338.1 g / 13.1 N
low risk
2 mm 1870 Gs
187.0 mT
0.83 kg / 1.83 LBS
830.9 g / 8.2 N
low risk
3 mm 1416 Gs
141.6 mT
0.48 kg / 1.05 LBS
476.6 g / 4.7 N
low risk
5 mm 785 Gs
78.5 mT
0.15 kg / 0.32 LBS
146.4 g / 1.4 N
low risk
10 mm 214 Gs
21.4 mT
0.01 kg / 0.02 LBS
10.9 g / 0.1 N
low risk
15 mm 81 Gs
8.1 mT
0.00 kg / 0.00 LBS
1.6 g / 0.0 N
low risk
20 mm 38 Gs
3.8 mT
0.00 kg / 0.00 LBS
0.3 g / 0.0 N
low risk
30 mm 12 Gs
1.2 mT
0.00 kg / 0.00 LBS
0.0 g / 0.0 N
low risk
50 mm 3 Gs
0.3 mT
0.00 kg / 0.00 LBS
0.0 g / 0.0 N
low risk

Table 2: Slippage hold (wall)
MP 10x7/3.5x3 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 0.38 kg / 0.83 LBS
376.0 g / 3.7 N
1 mm Stal (~0.2) 0.27 kg / 0.59 LBS
268.0 g / 2.6 N
2 mm Stal (~0.2) 0.17 kg / 0.37 LBS
166.0 g / 1.6 N
3 mm Stal (~0.2) 0.10 kg / 0.21 LBS
96.0 g / 0.9 N
5 mm Stal (~0.2) 0.03 kg / 0.07 LBS
30.0 g / 0.3 N
10 mm Stal (~0.2) 0.00 kg / 0.00 LBS
2.0 g / 0.0 N
15 mm Stal (~0.2) 0.00 kg / 0.00 LBS
0.0 g / 0.0 N
20 mm Stal (~0.2) 0.00 kg / 0.00 LBS
0.0 g / 0.0 N
30 mm Stal (~0.2) 0.00 kg / 0.00 LBS
0.0 g / 0.0 N
50 mm Stal (~0.2) 0.00 kg / 0.00 LBS
0.0 g / 0.0 N

Table 3: Wall mounting (sliding) - behavior on slippery surfaces
MP 10x7/3.5x3 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
0.56 kg / 1.24 LBS
564.0 g / 5.5 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
0.38 kg / 0.83 LBS
376.0 g / 3.7 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
0.19 kg / 0.41 LBS
188.0 g / 1.8 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
0.94 kg / 2.07 LBS
940.0 g / 9.2 N

Table 4: Material efficiency (substrate influence) - sheet metal selection
MP 10x7/3.5x3 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
10%
0.19 kg / 0.41 LBS
188.0 g / 1.8 N
1 mm
25%
0.47 kg / 1.04 LBS
470.0 g / 4.6 N
2 mm
50%
0.94 kg / 2.07 LBS
940.0 g / 9.2 N
3 mm
75%
1.41 kg / 3.11 LBS
1410.0 g / 13.8 N
5 mm
100%
1.88 kg / 4.14 LBS
1880.0 g / 18.4 N
10 mm
100%
1.88 kg / 4.14 LBS
1880.0 g / 18.4 N
11 mm
100%
1.88 kg / 4.14 LBS
1880.0 g / 18.4 N
12 mm
100%
1.88 kg / 4.14 LBS
1880.0 g / 18.4 N

Table 5: Thermal stability (stability) - resistance threshold
MP 10x7/3.5x3 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 1.88 kg / 4.14 LBS
1880.0 g / 18.4 N
OK
40 °C -2.2% 1.84 kg / 4.05 LBS
1838.6 g / 18.0 N
OK
60 °C -4.4% 1.80 kg / 3.96 LBS
1797.3 g / 17.6 N
80 °C -6.6% 1.76 kg / 3.87 LBS
1755.9 g / 17.2 N
100 °C -28.8% 1.34 kg / 2.95 LBS
1338.6 g / 13.1 N

Table 6: Two magnets (attraction) - field range
MP 10x7/3.5x3 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Sliding Force (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 2.86 kg / 6.30 LBS
4 419 Gs
0.43 kg / 0.95 LBS
429 g / 4.2 N
N/A
1 mm 2.46 kg / 5.43 LBS
5 224 Gs
0.37 kg / 0.81 LBS
370 g / 3.6 N
2.22 kg / 4.89 LBS
~0 Gs
2 mm 2.03 kg / 4.49 LBS
4 747 Gs
0.31 kg / 0.67 LBS
305 g / 3.0 N
1.83 kg / 4.04 LBS
~0 Gs
3 mm 1.62 kg / 3.58 LBS
4 242 Gs
0.24 kg / 0.54 LBS
244 g / 2.4 N
1.46 kg / 3.22 LBS
~0 Gs
5 mm 0.96 kg / 2.12 LBS
3 266 Gs
0.14 kg / 0.32 LBS
144 g / 1.4 N
0.87 kg / 1.91 LBS
~0 Gs
10 mm 0.22 kg / 0.49 LBS
1 570 Gs
0.03 kg / 0.07 LBS
33 g / 0.3 N
0.20 kg / 0.44 LBS
~0 Gs
20 mm 0.02 kg / 0.04 LBS
429 Gs
0.00 kg / 0.01 LBS
2 g / 0.0 N
0.01 kg / 0.03 LBS
~0 Gs
50 mm 0.00 kg / 0.00 LBS
41 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs
60 mm 0.00 kg / 0.00 LBS
25 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs
70 mm 0.00 kg / 0.00 LBS
16 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs
80 mm 0.00 kg / 0.00 LBS
11 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs
90 mm 0.00 kg / 0.00 LBS
8 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs
100 mm 0.00 kg / 0.00 LBS
6 Gs
0.00 kg / 0.00 LBS
0 g / 0.0 N
0.00 kg / 0.00 LBS
~0 Gs

Table 7: Hazards (electronics) - warnings
MP 10x7/3.5x3 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 4.5 cm
Hearing aid 10 Gs (1.0 mT) 3.5 cm
Mechanical watch 20 Gs (2.0 mT) 3.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 2.0 cm
Car key 50 Gs (5.0 mT) 2.0 cm
Payment card 400 Gs (40.0 mT) 1.0 cm
HDD hard drive 600 Gs (60.0 mT) 1.0 cm

Table 8: Impact energy (kinetic energy) - warning
MP 10x7/3.5x3 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 26.06 km/h
(7.24 m/s)
0.04 J
30 mm 26.15 km/h
(7.26 m/s)
0.04 J
50 mm 26.15 km/h
(7.26 m/s)
0.04 J
100 mm 26.15 km/h
(7.26 m/s)
0.04 J

Table 9: Coating parameters (durability)
MP 10x7/3.5x3 / 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 10x7/3.5x3 / N38

Parameter Value SI Unit / Description
Magnetic Flux 1 899 Mx 19.0 µWb
Pc Coefficient 0.37 Low (Flat)

Table 11: Underwater work (magnet fishing)
MP 10x7/3.5x3 / N38

Environment Effective steel pull Effect
Air (land) 1.88 kg Standard
Water (riverbed) 2.15 kg
(+0.27 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. Wall mount (shear)

*Note: On a vertical surface, the magnet retains just a fraction of its nominal pull.

2. Efficiency vs thickness

*Thin steel (e.g. 0.5mm PC case) severely weakens the holding force.

3. Heat tolerance

*For N38 grade, the safety limit is 80°C.

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

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 0.37

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.

Engineering data and GPSR

Material specification

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: 030180-2026
Measurement Calculator

Pulling force


Magnetic Induction

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The ring-shaped magnet MP 10x7/3.5x3 / N38 is created for mechanical fastening, where glue might fail or be insufficient. Mounting is clean and reversible, unlike gluing. 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. One turn too many can destroy the magnet, so do it slowly. The flat screw head should evenly press the magnet. 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 does not ensure full waterproofing. 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. If you must use it outside, paint it with anti-corrosion paint after mounting.
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.
The presented product is a ring magnet with dimensions Ø10 mm (outer diameter) and height 3 mm. The pulling force of this model is an impressive 1.88 kg, which translates to 18.44 N in newtons. The mounting hole diameter is precisely 7/3.5 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.

Pros as well as cons of Nd2Fe14B magnets.

Strengths

Besides their stability, neodymium magnets are valued for these benefits:
  • Their magnetic field is durable, and after around ten years it decreases only by ~1% (according to research),
  • They are resistant to demagnetization induced by presence of other magnetic fields,
  • The use of an metallic coating of noble metals (nickel, gold, silver) causes the element to have aesthetics,
  • Magnets exhibit huge magnetic induction on the working surface,
  • Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and are able to act (depending on the shape) even at a temperature of 230°C or more...
  • Considering the ability of free molding and adaptation to unique projects, magnetic components can be modeled in a broad palette of shapes and sizes, which expands the range of possible applications,
  • Huge importance in electronics industry – they serve a role in hard drives, motor assemblies, precision medical tools, also complex engineering applications.
  • Thanks to concentrated force, small magnets offer high operating force, with minimal size,

Limitations

Disadvantages of neodymium magnets:
  • To avoid cracks upon strong impacts, we recommend using special steel holders. Such a solution protects the magnet and simultaneously improves its durability.
  • Neodymium magnets lose strength when exposed to high temperatures. After reaching 80°C, many of them experience permanent weakening of strength (a factor is the shape and dimensions of the magnet). We offer magnets specially adapted to work at temperatures up to 230°C marked [AH], which are extremely resistant to heat
  • They oxidize in a humid environment. For use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
  • Limited ability of creating threads in the magnet and complicated shapes - recommended is cover - magnet mounting.
  • Possible danger related to microscopic parts of magnets are risky, if swallowed, which is particularly important in the context of child health protection. Furthermore, small components of these products are able to disrupt the diagnostic process medical when they are in the body.
  • Higher cost of purchase is one of the disadvantages compared to ceramic magnets, especially in budget applications

Holding force characteristics

Highest magnetic holding forcewhat contributes to it?

Magnet power was defined for optimal configuration, including:
  • using a plate made of high-permeability steel, functioning as a ideal flux conductor
  • possessing a thickness of minimum 10 mm to ensure full flux closure
  • characterized by even structure
  • under conditions of ideal adhesion (metal-to-metal)
  • during detachment in a direction perpendicular to the mounting surface
  • at temperature room level

Determinants of lifting force in real conditions

Bear in mind that the application force may be lower subject to the following factors, in order of importance:
  • Space between surfaces – even a fraction of a millimeter of distance (caused e.g. by veneer or unevenness) drastically reduces the magnet efficiency, often by half at just 0.5 mm.
  • Force direction – remember that the magnet has greatest strength perpendicularly. Under sliding down, the holding force drops significantly, often to levels of 20-30% of the maximum value.
  • Base massiveness – too thin plate causes magnetic saturation, causing part of the power to be lost into the air.
  • Chemical composition of the base – low-carbon steel attracts best. Alloy admixtures reduce magnetic properties and lifting capacity.
  • Base smoothness – the more even the surface, the better the adhesion and stronger the hold. Unevenness acts like micro-gaps.
  • Heat – neodymium magnets have a negative temperature coefficient. When it is hot they lose power, and at low temperatures gain strength (up to a certain limit).

Holding force was tested on a smooth steel plate of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the load capacity is reduced by as much as fivefold. Moreover, even a slight gap between the magnet and the plate reduces the lifting capacity.

Warnings
Electronic devices

Very strong magnetic fields can erase data on credit cards, HDDs, and storage devices. Maintain a gap of min. 10 cm.

No play value

Strictly keep magnets out of reach of children. Ingestion danger is high, and the effects of magnets clamping inside the body are tragic.

Material brittleness

Watch out for shards. Magnets can fracture upon uncontrolled impact, ejecting sharp fragments into the air. Wear goggles.

Precision electronics

GPS units and mobile phones are highly susceptible to magnetism. Direct contact with a strong magnet can permanently damage the sensors in your phone.

Nickel coating and allergies

Warning for allergy sufferers: The Ni-Cu-Ni coating consists of nickel. If redness appears, immediately stop handling magnets and use protective gear.

Heat sensitivity

Standard neodymium magnets (grade N) lose magnetization when the temperature goes above 80°C. The loss of strength is permanent.

Mechanical processing

Dust produced during cutting of magnets is combustible. Avoid drilling into magnets without proper cooling and knowledge.

Pinching danger

Mind your fingers. Two large magnets will join instantly with a force of several hundred kilograms, destroying everything in their path. Exercise extreme caution!

Implant safety

Health Alert: Neodymium magnets can turn off pacemakers and defibrillators. Do not approach if you have medical devices.

Do not underestimate power

Handle magnets consciously. Their powerful strength can shock even professionals. Be vigilant and do not underestimate their force.

Caution! Looking for details? Check our post: Why are neodymium magnets dangerous?