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MP 30x6x10 / N38 - ring magnet

ring magnet

Catalog no 030197

GTIN/EAN: 5906301812142

5.00

Diameter

30 mm [±0,1 mm]

internal diameter Ø

6 mm [±0,1 mm]

Height

10 mm [±0,1 mm]

Weight

50.89 g

Magnetization Direction

↑ axial

Load capacity

20.71 kg / 203.16 N

Magnetic Induction

343.81 mT / 3438 Gs

Coating

[NiCuNi] Nickel

16.00 with VAT / pcs + price for transport

13.01 ZŁ net + 23% VAT / pcs

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Parameters and shape of a neodymium magnet can be calculated using our magnetic mass calculator.

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Physical properties - MP 30x6x10 / N38 - ring magnet

Specification / characteristics - MP 30x6x10 / N38 - ring magnet

properties
properties values
Cat. no. 030197
GTIN/EAN 5906301812142
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 30 mm [±0,1 mm]
internal diameter Ø 6 mm [±0,1 mm]
Height 10 mm [±0,1 mm]
Weight 50.89 g
Magnetization Direction ↑ axial
Load capacity ~ ? 20.71 kg / 203.16 N
Magnetic Induction ~ ? 343.81 mT / 3438 Gs
Coating [NiCuNi] Nickel
Manufacturing Tolerance ±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 30x6x10 / 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

Engineering modeling of the product - data

These information are the result of a mathematical calculation. Values rely on algorithms for the material Nd2Fe14B. Actual performance may differ. Please consider these calculations as a preliminary roadmap during assembly planning.

Table 1: Static pull force (pull vs gap) - interaction chart
MP 30x6x10 / N38

Distance (mm) Induction (Gauss) / mT Pull Force (kg/lbs/g/N) Risk Status
0 mm 5619 Gs
561.9 mT
20.71 kg / 45.66 pounds
20710.0 g / 203.2 N
crushing
1 mm 5241 Gs
524.1 mT
18.01 kg / 39.71 pounds
18011.7 g / 176.7 N
crushing
2 mm 4861 Gs
486.1 mT
15.50 kg / 34.17 pounds
15498.1 g / 152.0 N
crushing
3 mm 4490 Gs
449.0 mT
13.22 kg / 29.15 pounds
13223.5 g / 129.7 N
crushing
5 mm 3792 Gs
379.2 mT
9.43 kg / 20.79 pounds
9429.0 g / 92.5 N
strong
10 mm 2404 Gs
240.4 mT
3.79 kg / 8.36 pounds
3791.3 g / 37.2 N
strong
15 mm 1526 Gs
152.6 mT
1.53 kg / 3.37 pounds
1527.0 g / 15.0 N
weak grip
20 mm 1000 Gs
100.0 mT
0.66 kg / 1.45 pounds
655.5 g / 6.4 N
weak grip
30 mm 482 Gs
48.2 mT
0.15 kg / 0.34 pounds
152.6 g / 1.5 N
weak grip
50 mm 161 Gs
16.1 mT
0.02 kg / 0.04 pounds
17.0 g / 0.2 N
weak grip

Table 2: Shear capacity (vertical surface)
MP 30x6x10 / N38

Distance (mm) Friction coefficient Pull Force (kg/lbs/g/N)
0 mm Stal (~0.2) 4.14 kg / 9.13 pounds
4142.0 g / 40.6 N
1 mm Stal (~0.2) 3.60 kg / 7.94 pounds
3602.0 g / 35.3 N
2 mm Stal (~0.2) 3.10 kg / 6.83 pounds
3100.0 g / 30.4 N
3 mm Stal (~0.2) 2.64 kg / 5.83 pounds
2644.0 g / 25.9 N
5 mm Stal (~0.2) 1.89 kg / 4.16 pounds
1886.0 g / 18.5 N
10 mm Stal (~0.2) 0.76 kg / 1.67 pounds
758.0 g / 7.4 N
15 mm Stal (~0.2) 0.31 kg / 0.67 pounds
306.0 g / 3.0 N
20 mm Stal (~0.2) 0.13 kg / 0.29 pounds
132.0 g / 1.3 N
30 mm Stal (~0.2) 0.03 kg / 0.07 pounds
30.0 g / 0.3 N
50 mm Stal (~0.2) 0.00 kg / 0.01 pounds
4.0 g / 0.0 N

Table 3: Wall mounting (shearing) - vertical pull
MP 30x6x10 / N38

Surface type Friction coefficient / % Mocy Max load (kg/lbs/g/N)
Raw steel
µ = 0.3 30% Nominalnej Siły
6.21 kg / 13.70 pounds
6213.0 g / 60.9 N
Painted steel (standard)
µ = 0.2 20% Nominalnej Siły
4.14 kg / 9.13 pounds
4142.0 g / 40.6 N
Oily/slippery steel
µ = 0.1 10% Nominalnej Siły
2.07 kg / 4.57 pounds
2071.0 g / 20.3 N
Magnet with anti-slip rubber
µ = 0.5 50% Nominalnej Siły
10.36 kg / 22.83 pounds
10355.0 g / 101.6 N

Table 4: Steel thickness (saturation) - power losses
MP 30x6x10 / N38

Steel thickness (mm) % power Real pull force (kg/lbs/g/N)
0.5 mm
5%
1.04 kg / 2.28 pounds
1035.5 g / 10.2 N
1 mm
13%
2.59 kg / 5.71 pounds
2588.8 g / 25.4 N
2 mm
25%
5.18 kg / 11.41 pounds
5177.5 g / 50.8 N
3 mm
38%
7.77 kg / 17.12 pounds
7766.3 g / 76.2 N
5 mm
63%
12.94 kg / 28.54 pounds
12943.8 g / 127.0 N
10 mm
100%
20.71 kg / 45.66 pounds
20710.0 g / 203.2 N
11 mm
100%
20.71 kg / 45.66 pounds
20710.0 g / 203.2 N
12 mm
100%
20.71 kg / 45.66 pounds
20710.0 g / 203.2 N

Table 5: Working in heat (stability) - thermal limit
MP 30x6x10 / N38

Ambient temp. (°C) Power loss Remaining pull (kg/lbs/g/N) Status
20 °C 0.0% 20.71 kg / 45.66 pounds
20710.0 g / 203.2 N
OK
40 °C -2.2% 20.25 kg / 44.65 pounds
20254.4 g / 198.7 N
OK
60 °C -4.4% 19.80 kg / 43.65 pounds
19798.8 g / 194.2 N
OK
80 °C -6.6% 19.34 kg / 42.64 pounds
19343.1 g / 189.8 N
100 °C -28.8% 14.75 kg / 32.51 pounds
14745.5 g / 144.7 N

Table 6: Two magnets (repulsion) - field collision
MP 30x6x10 / N38

Gap (mm) Attraction (kg/lbs) (N-S) Shear Force (kg/lbs/g/N) Repulsion (kg/lbs) (N-N)
0 mm 103.97 kg / 229.22 pounds
6 035 Gs
15.60 kg / 34.38 pounds
15596 g / 153.0 N
N/A
1 mm 97.15 kg / 214.17 pounds
10 864 Gs
14.57 kg / 32.13 pounds
14572 g / 143.0 N
87.43 kg / 192.75 pounds
~0 Gs
2 mm 90.42 kg / 199.35 pounds
10 481 Gs
13.56 kg / 29.90 pounds
13564 g / 133.1 N
81.38 kg / 179.42 pounds
~0 Gs
3 mm 83.97 kg / 185.13 pounds
10 100 Gs
12.60 kg / 27.77 pounds
12596 g / 123.6 N
75.57 kg / 166.61 pounds
~0 Gs
5 mm 71.94 kg / 158.60 pounds
9 349 Gs
10.79 kg / 23.79 pounds
10791 g / 105.9 N
64.75 kg / 142.74 pounds
~0 Gs
10 mm 47.34 kg / 104.36 pounds
7 583 Gs
7.10 kg / 15.65 pounds
7100 g / 69.7 N
42.60 kg / 93.92 pounds
~0 Gs
20 mm 19.03 kg / 41.96 pounds
4 809 Gs
2.86 kg / 6.29 pounds
2855 g / 28.0 N
17.13 kg / 37.77 pounds
~0 Gs
50 mm 1.53 kg / 3.37 pounds
1 363 Gs
0.23 kg / 0.51 pounds
229 g / 2.2 N
1.38 kg / 3.03 pounds
~0 Gs
60 mm 0.77 kg / 1.69 pounds
965 Gs
0.11 kg / 0.25 pounds
115 g / 1.1 N
0.69 kg / 1.52 pounds
~0 Gs
70 mm 0.41 kg / 0.90 pounds
706 Gs
0.06 kg / 0.14 pounds
61 g / 0.6 N
0.37 kg / 0.81 pounds
~0 Gs
80 mm 0.23 kg / 0.51 pounds
531 Gs
0.03 kg / 0.08 pounds
35 g / 0.3 N
0.21 kg / 0.46 pounds
~0 Gs
90 mm 0.14 kg / 0.30 pounds
409 Gs
0.02 kg / 0.05 pounds
21 g / 0.2 N
0.12 kg / 0.27 pounds
~0 Gs
100 mm 0.09 kg / 0.19 pounds
322 Gs
0.01 kg / 0.03 pounds
13 g / 0.1 N
0.08 kg / 0.17 pounds
~0 Gs

Table 7: Hazards (implants) - warnings
MP 30x6x10 / N38

Object / Device Limit (Gauss) / mT Safe distance
Pacemaker 5 Gs (0.5 mT) 19.5 cm
Hearing aid 10 Gs (1.0 mT) 15.0 cm
Mechanical watch 20 Gs (2.0 mT) 12.0 cm
Phone / Smartphone 40 Gs (4.0 mT) 9.0 cm
Remote 50 Gs (5.0 mT) 8.5 cm
Payment card 400 Gs (40.0 mT) 3.5 cm
HDD hard drive 600 Gs (60.0 mT) 3.0 cm

Table 8: Dynamics (cracking risk) - collision effects
MP 30x6x10 / N38

Start from (mm) Speed (km/h) Energy (J) Predicted outcome
10 mm 22.55 km/h
(6.26 m/s)
1.00 J
30 mm 35.40 km/h
(9.83 m/s)
2.46 J
50 mm 45.52 km/h
(12.64 m/s)
4.07 J
100 mm 64.34 km/h
(17.87 m/s)
8.13 J

Table 9: Surface protection spec
MP 30x6x10 / 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 30x6x10 / N38

Parameter Value SI Unit / Description
Magnetic Flux 31 585 Mx 315.8 µWb
Pc Coefficient 0.96 High (Stable)

Table 11: Underwater work (magnet fishing)
MP 30x6x10 / N38

Environment Effective steel pull Effect
Air (land) 20.71 kg Standard
Water (riverbed) 23.71 kg
(+3.00 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

*Warning: On a vertical wall, the magnet retains merely ~20% of its max power.

2. Steel saturation

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

3. Thermal stability

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

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

chart generated for the permeance coefficient Pc (Permeance Coefficient) = 0.96

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 and environmental data
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%
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: 030197-2026
Quick Unit Converter
Pulling force

Field Strength

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The ring-shaped magnet MP 30x6x10 / N38 is created for mechanical fastening, where glue might fail or be insufficient. 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 is a crucial issue when working with model MP 30x6x10 / N38. Neodymium magnets are sintered ceramics, which means they are hard but breakable and inelastic. 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.
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. This product is dedicated for inside building use. For outdoor applications, we recommend choosing rubberized holders or additional protection with varnish.
The inner hole diameter determines the maximum size of the mounting element. For magnets with a straight hole, a conical head can act like a wedge and burst the magnet. Always check that the screw head is not larger than the outer diameter of the magnet (30 mm), so it doesn't protrude beyond the outline.
It is a magnetic ring with a diameter of 30 mm and thickness 10 mm. The pulling force of this model is an impressive 20.71 kg, which translates to 203.16 N in newtons. The mounting hole diameter is precisely 6 mm.
The poles are located on the planes with holes, not on the sides of the ring. In the case of connecting two rings, make sure one is turned the right way. When ordering a larger quantity, magnets are usually packed in stacks, where they are already naturally paired.

Advantages as well as disadvantages of rare earth magnets.

Advantages

Besides their stability, 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% (according to literature),
  • They show high resistance to demagnetization induced by external magnetic fields,
  • Thanks to the smooth finish, the layer of nickel, gold-plated, or silver-plated gives an visually attractive appearance,
  • Neodymium magnets create maximum magnetic induction on a small surface, which allows for strong attraction,
  • Thanks to resistance to high temperature, they are able to function (depending on the form) even at temperatures up to 230°C and higher...
  • Thanks to the option of flexible forming and customization to specialized projects, magnetic components can be created in a broad palette of shapes and sizes, which makes them more universal,
  • Huge importance in innovative solutions – they are utilized in hard drives, brushless drives, diagnostic systems, as well as technologically advanced constructions.
  • Thanks to concentrated force, small magnets offer high operating force, in miniature format,

Cons

Disadvantages of neodymium magnets:
  • They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets in a protective case. Such protection not only shields the magnet but also improves its resistance to damage
  • When exposed to high temperature, neodymium magnets suffer a drop in strength. 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 recommend using water-impermeable magnets made of rubber, plastic or other material protecting against moisture
  • We suggest casing - magnetic holder, due to difficulties in producing threads inside the magnet and complex shapes.
  • Health risk to health – tiny shards of magnets can be dangerous, if swallowed, which is particularly important in the context of child health protection. It is also worth noting that small components of these devices can complicate diagnosis medical when they are in the body.
  • Higher cost of purchase is a significant factor to consider compared to ceramic magnets, especially in budget applications

Lifting parameters

Magnetic strength at its maximum – what affects it?

The declared magnet strength refers to the maximum value, obtained under ideal test conditions, meaning:
  • with the application of a sheet made of special test steel, ensuring maximum field concentration
  • possessing a thickness of minimum 10 mm to ensure full flux closure
  • with a plane perfectly flat
  • with direct contact (without impurities)
  • under perpendicular application of breakaway force (90-degree angle)
  • in temp. approx. 20°C

Impact of factors on magnetic holding capacity in practice

Holding efficiency impacted by working environment parameters, including (from priority):
  • Clearance – existence of any layer (paint, dirt, gap) interrupts the magnetic circuit, which lowers power rapidly (even by 50% at 0.5 mm).
  • Force direction – catalog parameter refers to detachment vertically. When attempting to slide, the magnet holds much less (typically approx. 20-30% of maximum force).
  • Plate thickness – too thin plate does not close the flux, causing part of the power to be wasted to the other side.
  • Metal type – not every steel attracts identically. Alloy additives worsen the interaction with the magnet.
  • Surface condition – smooth surfaces ensure maximum contact, which increases field saturation. Uneven metal weaken the grip.
  • Operating temperature – neodymium magnets have a sensitivity to temperature. At higher temperatures they lose power, and at low temperatures they can be stronger (up to a certain limit).

Lifting capacity testing was carried out on a smooth plate of suitable thickness, under a perpendicular pulling force, in contrast under shearing force the load capacity is reduced by as much as 5 times. In addition, even a slight gap between the magnet and the plate decreases the lifting capacity.

Warnings
Risk of cracking

Watch out for shards. Magnets can fracture upon uncontrolled impact, ejecting sharp fragments into the air. Eye protection is mandatory.

Adults only

Only for adults. Tiny parts pose a choking risk, leading to intestinal necrosis. Keep out of reach of children and animals.

GPS Danger

GPS units and smartphones are extremely susceptible to magnetism. Direct contact with a strong magnet can ruin the sensors in your phone.

Safe distance

Data protection: Neodymium magnets can ruin data carriers and delicate electronics (pacemakers, hearing aids, mechanical watches).

Avoid contact if allergic

Warning for allergy sufferers: The nickel-copper-nickel coating consists of nickel. If an allergic reaction appears, cease handling magnets and use protective gear.

Flammability

Powder produced during grinding of magnets is flammable. Avoid drilling into magnets without proper cooling and knowledge.

Bone fractures

Risk of injury: The attraction force is so great that it can cause blood blisters, pinching, and broken bones. Protective gloves are recommended.

Immense force

Exercise caution. Neodymium magnets act from a long distance and connect with massive power, often faster than you can move away.

Medical interference

For implant holders: Strong magnetic fields affect medical devices. Maintain at least 30 cm distance or ask another person to handle the magnets.

Maximum temperature

Standard neodymium magnets (grade N) undergo demagnetization when the temperature exceeds 80°C. Damage is permanent.

Security! Need more info? Read our article: Are neodymium magnets dangerous?
Dhit sp. z o.o.

e-mail: bok@dhit.pl

tel: +48 888 99 98 98