Product on order Ships in 3-5 days

MP 25x13x4 / N38 - ring magnet

Name: Dhit sp. z o.o.
Address: Kościuszki 6A, Ożarów Mazowiecki, Poland, 05-850, PL
Telephone: +48 22 499 98 98
Price range: PLN 1-6500
Rating: 5

ring magnet

Catalog no 030190

GTIN/EAN: 5906301812074

5.00

Diameter

25 mm [±0,1 mm]

internal diameter Ø

13 mm [±0,1 mm]

Height

4 mm [±0,1 mm]

Weight

10.74 g

Magnetization Direction

↑ axial

Load capacity

4.14 kg / 40.57 N

Magnetic Induction

188.92 mT / 1889 Gs

Coating

[NiCuNi] Nickel

view specifications »

6.77 ZŁ with VAT / pcs + price for transport

5.50 ZŁ net + 23% VAT / pcs

bulk discounts:

Need more?

price from 1 pcs

5.50 ZŁ

6.77 ZŁ

price from 150 pcs

5.17 ZŁ

6.36 ZŁ

price from 500 pcs

4.84 ZŁ

5.95 ZŁ

Carbon Footprint – environmental impact GPSR Regulation – product safety

Looking for a better price?

Call us +48 22 499 98 98 alternatively let us know by means of our online form the contact form page.
Specifications along with structure of a neodymium magnet can be analyzed using our force calculator.

Order by 14:00 and we’ll ship today!

Product card - MP 25x13x4 / N38 - ring magnet

Specification / characteristics - MP 25x13x4 / N38 - ring magnet

properties

properties	values
Cat. no.	030190
GTIN/EAN	5906301812074
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	25 mm [±0,1 mm]
internal diameter Ø	13 mm [±0,1 mm]
Height	4 mm [±0,1 mm]
Weight	10.74 g
Magnetization Direction	↑ axial
Load capacity ~ ?	4.14 kg / 40.57 N
Magnetic Induction ~ ?	188.92 mT / 1889 Gs
Coating	[NiCuNi] Nickel
Manufacturing Tolerance	±0.1 mm

Magnetic properties of material N38

Specification / characteristics MP 25x13x4 / 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

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 simulation of the product - report

These data represent the outcome of a mathematical analysis. Results rely on models for the class Nd₂Fe₁₄B. Operational performance may differ. Use these data as a supplementary guide during assembly planning.

Table 1: Static force (pull vs gap) - characteristics
MP 25x13x4 / N38

Distance (mm)	Induction (Gauss) / mT	Pull Force (kg/lbs/g/N)	Risk Status
0 mm	5777 Gs 577.7 mT	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N	strong
1 mm	5310 Gs 531.0 mT	3.50 kg / 7.71 lbs 3497.4 g / 34.3 N	strong
2 mm	4846 Gs 484.6 mT	2.91 kg / 6.42 lbs 2912.4 g / 28.6 N	strong
3 mm	4397 Gs 439.7 mT	2.40 kg / 5.29 lbs 2398.5 g / 23.5 N	strong
5 mm	3576 Gs 357.6 mT	1.59 kg / 3.50 lbs 1586.2 g / 15.6 N	low risk
10 mm	2073 Gs 207.3 mT	0.53 kg / 1.17 lbs 532.9 g / 5.2 N	low risk
15 mm	1231 Gs 123.1 mT	0.19 kg / 0.41 lbs 188.0 g / 1.8 N	low risk
20 mm	773 Gs 77.3 mT	0.07 kg / 0.16 lbs 74.0 g / 0.7 N	low risk
30 mm	356 Gs 35.6 mT	0.02 kg / 0.03 lbs 15.7 g / 0.2 N	low risk
50 mm	115 Gs 11.5 mT	0.00 kg / 0.00 lbs 1.6 g / 0.0 N	low risk

Grip strength decreases drastically per each millimeter of distance. Keep in mind that every additional insulation layer (e.g., dirt, varnish, rust) noticeably weakens the grip. Magnetic products operate strongest at the point of direct contact; distance weakens the force. Observe how quickly the load capacity fall, when the product does not touch tightly to the steel surface. When planning the assembly, avoid unnecessary gaps.

Table 2: Shear hold (wall)
MP 25x13x4 / N38

Distance (mm)	Friction coefficient	Pull Force (kg/lbs/g/N)
0 mm	Stal (~0.2)	0.83 kg / 1.83 lbs 828.0 g / 8.1 N
1 mm	Stal (~0.2)	0.70 kg / 1.54 lbs 700.0 g / 6.9 N
2 mm	Stal (~0.2)	0.58 kg / 1.28 lbs 582.0 g / 5.7 N
3 mm	Stal (~0.2)	0.48 kg / 1.06 lbs 480.0 g / 4.7 N
5 mm	Stal (~0.2)	0.32 kg / 0.70 lbs 318.0 g / 3.1 N
10 mm	Stal (~0.2)	0.11 kg / 0.23 lbs 106.0 g / 1.0 N
15 mm	Stal (~0.2)	0.04 kg / 0.08 lbs 38.0 g / 0.4 N
20 mm	Stal (~0.2)	0.01 kg / 0.03 lbs 14.0 g / 0.1 N
30 mm	Stal (~0.2)	0.00 kg / 0.01 lbs 4.0 g / 0.0 N
50 mm	Stal (~0.2)	0.00 kg / 0.00 lbs 0.0 g / 0.0 N

The following data indicates the approximate shear load necessary to initiate the downward movement of the magnet down along a vertical metal surface (considering typical friction coefficient). The holding force varies with the air gap between the magnet and the metal.

Table 3: Vertical assembly (sliding) - behavior on slippery surfaces
MP 25x13x4 / N38

Surface type	Friction coefficient / % Mocy	Max load (kg/lbs/g/N)
Raw steel	µ = 0.3 30% Nominalnej Siły	1.24 kg / 2.74 lbs 1242.0 g / 12.2 N
Painted steel (standard)	µ = 0.2 20% Nominalnej Siły	0.83 kg / 1.83 lbs 828.0 g / 8.1 N
Oily/slippery steel	µ = 0.1 10% Nominalnej Siły	0.41 kg / 0.91 lbs 414.0 g / 4.1 N
Magnet with anti-slip rubber	µ = 0.5 50% Nominalnej Siły	2.07 kg / 4.56 lbs 2070.0 g / 20.3 N

When mounting a holder on a vertical wall (e.g., a car body), it will maintain barely approx. 1/5 of nominal attraction strength. Gravity and a weak degree of grip cause that products slip easier than they pull off. Designing a vertical fastening? Remember that the sliding force is much weaker than the maximum static pull force. On a smooth steel, the magnet will slip down under a much lighter weight. Application of an anti-slip pad can drastically raise the stability.

Table 4: Material efficiency (saturation) - power losses
MP 25x13x4 / N38

Steel thickness (mm)	% power	Real pull force (kg/lbs/g/N)
0.5 mm	10%	0.41 kg / 0.91 lbs 414.0 g / 4.1 N
1 mm	25%	1.04 kg / 2.28 lbs 1035.0 g / 10.2 N
2 mm	50%	2.07 kg / 4.56 lbs 2070.0 g / 20.3 N
3 mm	75%	3.10 kg / 6.85 lbs 3105.0 g / 30.5 N
5 mm	100%	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N
10 mm	100%	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N
11 mm	100%	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N
12 mm	100%	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N

A thin sheet is unable to conduct the full magnetic flux, which squanders power of the holder. Should you install a neodymium to a thin surface, the magnetism will pass right through and the attraction force will be weaker. To utilize full efficiency of this magnet's potential, you require a sufficiently solid element of metal. The saturation phenomenon causes that on delicate walls (e.g., car bodies), the magnet shows lower pull force. We advise picking the steel thickness based on the following data.

Table 5: Thermal stability (stability) - resistance threshold
MP 25x13x4 / N38

Ambient temp. (°C)	Power loss	Remaining pull (kg/lbs/g/N)	Status
20 °C	0.0%	4.14 kg / 9.13 lbs 4140.0 g / 40.6 N	OK
40 °C	-2.2%	4.05 kg / 8.93 lbs 4048.9 g / 39.7 N	OK
60 °C	-4.4%	3.96 kg / 8.73 lbs 3957.8 g / 38.8 N	OK
80 °C	-6.6%	3.87 kg / 8.52 lbs 3866.8 g / 37.9 N
100 °C	-28.8%	2.95 kg / 6.50 lbs 2947.7 g / 28.9 N

Ordinary NdFeB products change their properties power past the thermal threshold. Protect against heat – excessive heat can permanently demagnetize this magnet. As the temperature rises, the neodymium's force temporarily lowers. Avoid using this magnet in hot environments higher than its safe range. Too high temperature will result in irreversible degradation of magnetism.

*Engineering note: Heat tolerance is determined by both grade, and the Permeance Coefficient Pc. Flat magnets (low Pc) risk losing magnetic properties under lower heat stress than taller cylinders. The danger warning in the table signals permanent field degradation for this specific geometry.

Table 6: Magnet-Magnet interaction (repulsion) - forces in the system
MP 25x13x4 / N38

Gap (mm)	Attraction (kg/lbs) (N-S)	Lateral Force (kg/lbs/g/N)	Repulsion (kg/lbs) (N-N)
0 mm	83.66 kg / 184.44 lbs 6 082 Gs	12.55 kg / 27.67 lbs 12549 g / 123.1 N	N/A
1 mm	77.09 kg / 169.95 lbs 11 091 Gs	11.56 kg / 25.49 lbs 11563 g / 113.4 N	69.38 kg / 152.95 lbs ~0 Gs
2 mm	70.68 kg / 155.81 lbs 10 620 Gs	10.60 kg / 23.37 lbs 10601 g / 104.0 N	63.61 kg / 140.23 lbs ~0 Gs
3 mm	64.59 kg / 142.40 lbs 10 153 Gs	9.69 kg / 21.36 lbs 9689 g / 95.0 N	58.13 kg / 128.16 lbs ~0 Gs
5 mm	53.48 kg / 117.90 lbs 9 238 Gs	8.02 kg / 17.68 lbs 8022 g / 78.7 N	48.13 kg / 106.11 lbs ~0 Gs
10 mm	32.05 kg / 70.66 lbs 7 152 Gs	4.81 kg / 10.60 lbs 4808 g / 47.2 N	28.85 kg / 63.60 lbs ~0 Gs
20 mm	10.77 kg / 23.74 lbs 4 145 Gs	1.62 kg / 3.56 lbs 1615 g / 15.8 N	9.69 kg / 21.37 lbs ~0 Gs
50 mm	0.66 kg / 1.45 lbs 1 024 Gs	0.10 kg / 0.22 lbs 99 g / 1.0 N	0.59 kg / 1.30 lbs ~0 Gs
60 mm	0.32 kg / 0.70 lbs 712 Gs	0.05 kg / 0.10 lbs 48 g / 0.5 N	0.29 kg / 0.63 lbs ~0 Gs
70 mm	0.17 kg / 0.36 lbs 514 Gs	0.02 kg / 0.05 lbs 25 g / 0.2 N	0.15 kg / 0.33 lbs ~0 Gs
80 mm	0.09 kg / 0.20 lbs 383 Gs	0.01 kg / 0.03 lbs 14 g / 0.1 N	0.08 kg / 0.18 lbs ~0 Gs
90 mm	0.05 kg / 0.12 lbs 293 Gs	0.01 kg / 0.02 lbs 8 g / 0.1 N	0.05 kg / 0.11 lbs ~0 Gs
100 mm	0.03 kg / 0.07 lbs 230 Gs	0.00 kg / 0.01 lbs 5 g / 0.0 N	0.03 kg / 0.07 lbs ~0 Gs

Two magnets interact from a much further distance than a neodymium and metal setup. Such a system of two magnets creates a more powerful interaction and a further horizon of action. Planning to create a solid fastener? Use a pair of magnets instead of one magnet and a steel. Be careful that when attracting two neodymiums, the pinch force is massive. The repulsion force is slightly lower than the connection force, but still significant.
*Flux density between like poles reaches ~0 Gs at the geometric center of the gap (due to field cancellation).
Note: Figures show friction force of dual same magnets (friction ~0.15 for Ni-Ni coating).

Table 7: Hazards (electronics) - precautionary measures
MP 25x13x4 / N38

Object / Device	Limit (Gauss) / mT	Safe distance
Pacemaker	5 Gs (0.5 mT)	17.0 cm
Hearing aid	10 Gs (1.0 mT)	13.5 cm
Mechanical watch	20 Gs (2.0 mT)	10.5 cm
Mobile device	40 Gs (4.0 mT)	8.0 cm
Remote	50 Gs (5.0 mT)	7.5 cm
Payment card	400 Gs (40.0 mT)	3.0 cm
HDD hard drive	600 Gs (60.0 mT)	2.5 cm

Powerful magnet radiation poses a serious hazard to IT equipment and medical implants. These NdFeB products produce a field that prevents correct functioning of sensitive medical devices. Remember: the invisible magnetic field penetrates the body and housings. Exceptional care must be taken by people with hearing aids and insulin pumps. Influence will be felt by: mechanical watches, car keys, speakers, and displays. Do not place the magnet near cards, hard drives, or precise measuring instruments.

Table 8: Impact energy (kinetic energy) - collision effects
MP 25x13x4 / N38

Start from (mm)	Speed (km/h)	Energy (J)
10 mm	21.33 km/h (5.93 m/s)	0.19 J
30 mm	34.38 km/h (9.55 m/s)	0.49 J
50 mm	44.29 km/h (12.30 m/s)	0.81 J
100 mm	62.62 km/h (17.39 m/s)	1.62 J

Neodymium magnets are very brittle – a violent impact against metal causes immediate chipping. Pay attention to connection velocity – a neodymium left loose turns into a projectile. Impact energy can trigger coating fragments or painful pinches to fingers. Be sure to control the product during bringing near metal so it doesn't hit violently against the metal. A contact at a velocity of dozens of km/h almost guarantees destruction of the magnet. Use safety goggles when handling with large magnets.

Table 9: Coating parameters (durability)
MP 25x13x4 / 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)

The following table defines the conditions under which this product can be safely used. The silver nickel coating also serves an aesthetic function but is not fully waterproof.

Table 10: Construction data (P_c)
MP 25x13x4 / N38

Parameter	Value	SI Unit / Description
Magnetic Flux	24 861 Mx	248.6 µWb
P_c Coefficient	1.02	High (Stable)

Total magnetic flux passing through the pole surface. Key data when building generators and motors. P_c value determines the magnet's operating point.

Table 11: Physics of underwater searching
MP 25x13x4 / N38

Environment	Effective steel pull	Effect
Air (land)	4.14 kg	Standard
Water (riverbed)	4.74 kg (+0.60 kg buoyancy gain)	+14.5%

Corrosion warning: Standard nickel requires drying after every contact with moisture; lack of maintenance will lead to rust spots.

Water displaces steel, making heavy objects slightly lighter. As a result, your magnet will pull a heavier object from the bottom than if you lifted it in the air.

1. Sliding resistance

*Note: On a vertical wall, the magnet holds merely approx. 20-30% of its max power.

2. Efficiency vs thickness

*Thin steel (e.g. 0.5mm PC case) significantly reduces the holding force.

3. Power loss vs temp

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

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

chart generated for the permeance coefficient P_c (Permeance Coefficient) = 1.02

This simulation demonstrates the magnetic stability of the selected magnet under specific geometric conditions. 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 P_c (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 P_c 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

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: 030190-2026

Quick Unit Converter

Force (pull)

Kilograms (kg)

lbs

Magnetic Field

Gauss (Gs)

Tesla (T)

Input a value in a box, and the rest convert automatically.

View also deals

Product on order Ships in 3-5 days

SMZR 32x200 / N52 - magnetic separator with handle

615.00 ZŁ brutto / pcs

Product on order Ships in 3-5 days

MW 100x30 / N38 - cylindrical magnet

650.01 ZŁ brutto / pcs

Product on order Ships in 3-5 days

MP 25x7.5/4.5x5 / N38 - ring magnet

8.00 ZŁ brutto / pcs

Product on order Ships in 3-5 days

MPL 10x10x10 / N38 - lamellar magnet

5.29 ZŁ brutto / pcs

It is ideally suited for places where solid attachment of the magnet to the substrate is required without the risk of detachment. Mounting is clean and reversible, unlike gluing. This product with a force of 4.14 kg works great as a cabinet closure, speaker holder, or spacer element in devices.

This is a crucial issue when working with model MP 25x13x4 / N38. Neodymium magnets are sintered ceramics, which means they are hard but breakable and inelastic. 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.

Moisture can penetrate micro-cracks in the coating and cause oxidation of the magnet. In the place of the mounting hole, the coating is thinner and easily scratched when tightening the screw, which will become a corrosion focus. This product is dedicated for inside building use. For outdoor applications, we recommend choosing rubberized holders or additional protection with varnish.

A screw or bolt with a thread diameter smaller than 13 mm fits this model. 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. Always check that the screw head is not larger than the outer diameter of the magnet (25 mm), so it doesn't protrude beyond the outline.

It is a magnetic ring with a diameter of 25 mm and thickness 4 mm. The pulling force of this model is an impressive 4.14 kg, which translates to 40.57 N in newtons. The mounting hole diameter is precisely 13 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. When ordering a larger quantity, magnets are usually packed in stacks, where they are already naturally paired.

Strengths as well as weaknesses of rare earth magnets.

Benefits

In addition to their magnetic efficiency, neodymium magnets provide the following advantages:

They have stable power, and over around ten years their attraction force decreases symbolically – ~1% (according to theory),
They have excellent resistance to magnetic field loss when exposed to external magnetic sources,
In other words, due to the glossy surface of nickel, the element becomes visually attractive,
They show high magnetic induction at the operating surface, which increases their power,
Made from properly selected components, these magnets show impressive resistance to high heat, enabling them to function (depending on their shape) at temperatures up to 230°C and above...
Possibility of exact machining as well as optimizing to defined needs,
Significant place in modern technologies – they are used in data components, electric drive systems, diagnostic systems, also technologically advanced constructions.
Relatively small size with high pulling force – neodymium magnets offer high power in compact dimensions, which makes them useful in small systems

Disadvantages

Characteristics of disadvantages of neodymium magnets: weaknesses and usage proposals

They are prone to damage upon heavy impacts. To avoid cracks, it is worth protecting magnets using a steel holder. Such protection not only protects the magnet but also improves its resistance to damage
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
They rust in a humid environment - during use outdoors we suggest using waterproof magnets e.g. in rubber, plastic
Limited possibility of making threads in the magnet and complex shapes - recommended is casing - magnetic holder.
Possible danger related to microscopic parts of magnets pose a threat, if swallowed, which gains importance in the context of child safety. Furthermore, small components of these products can complicate diagnosis medical when they are in the body.
High unit price – neodymium magnets have a higher price than other types of magnets (e.g. ferrite), which can limit application in large quantities

Lifting parameters

Maximum holding power of the magnet – what it depends on?

Information about lifting capacity was determined for ideal contact conditions, assuming:

on a base made of structural steel, optimally conducting the magnetic flux
whose thickness equals approx. 10 mm
characterized by lack of roughness
under conditions of gap-free contact (surface-to-surface)
during pulling in a direction perpendicular to the plane
at room temperature

Practical lifting capacity: influencing factors

Please note that the application force may be lower subject to elements below, starting with the most relevant:

Clearance – existence of foreign body (paint, dirt, air) interrupts the magnetic circuit, which lowers power steeply (even by 50% at 0.5 mm).
Direction of force – maximum parameter is obtained only during pulling at a 90° angle. The shear force of the magnet along the plate is usually many times smaller (approx. 1/5 of the lifting capacity).
Wall thickness – the thinner the sheet, the weaker the hold. Magnetic flux penetrates through instead of generating force.
Material composition – different alloys attracts identically. Alloy additives worsen the interaction with the magnet.
Surface structure – the more even the plate, the larger the contact zone and higher the lifting capacity. Unevenness creates an air distance.
Thermal factor – hot environment weakens pulling force. Exceeding the limit temperature can permanently demagnetize the magnet.

Holding force was measured on the plate surface of 20 mm thickness, when a perpendicular force was applied, however under parallel forces the lifting capacity is smaller. Moreover, even a small distance between the magnet and the plate lowers the load capacity.

Precautions when working with NdFeB magnets

Do not underestimate power

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

Warning for allergy sufferers

Allergy Notice: The Ni-Cu-Ni coating consists of nickel. If redness appears, cease handling magnets and use protective gear.

Hand protection

Mind your fingers. Two large magnets will snap together instantly with a force of massive weight, crushing everything in their path. Exercise extreme caution!

Power loss in heat

Monitor thermal conditions. Heating the magnet above 80 degrees Celsius will destroy its magnetic structure and pulling force.

Life threat

For implant holders: Strong magnetic fields affect medical devices. Keep minimum 30 cm distance or ask another person to work with the magnets.

Dust is flammable

Fire hazard: Rare earth powder is highly flammable. Avoid machining magnets in home conditions as this may cause fire.

Keep away from electronics

A strong magnetic field interferes with the functioning of magnetometers in phones and GPS navigation. Keep magnets near a device to prevent damaging the sensors.

Do not give to children

Product intended for adults. Small elements can be swallowed, causing severe trauma. Keep out of reach of kids and pets.

Magnets are brittle

NdFeB magnets are sintered ceramics, which means they are very brittle. Impact of two magnets leads to them cracking into small pieces.

Cards and drives

Powerful magnetic fields can corrupt files on credit cards, hard drives, and other magnetic media. Maintain a gap of min. 10 cm.

Warning! Need more info? Read our article: Are neodymium magnets dangerous?

MP 25x13x4 / N38 - ring magnet

Product card - MP 25x13x4 / N38 - ring magnet

Magnetic properties of material N38

Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C

Physical simulation of the product - report

Table 1: Static force (pull vs gap) - characteristics MP 25x13x4 / N38

Table 2: Shear hold (wall) MP 25x13x4 / N38

Table 3: Vertical assembly (sliding) - behavior on slippery surfaces MP 25x13x4 / N38

Table 4: Material efficiency (saturation) - power losses MP 25x13x4 / N38

Table 5: Thermal stability (stability) - resistance threshold MP 25x13x4 / N38

Table 6: Magnet-Magnet interaction (repulsion) - forces in the system MP 25x13x4 / N38

Table 7: Hazards (electronics) - precautionary measures MP 25x13x4 / N38

Table 8: Impact energy (kinetic energy) - collision effects MP 25x13x4 / N38

Table 9: Coating parameters (durability) MP 25x13x4 / N38

Table 10: Construction data (Pc) MP 25x13x4 / N38

Table 11: Physics of underwater searching MP 25x13x4 / N38

1. Sliding resistance

2. Efficiency vs thickness

3. Power loss vs temp

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

Material specification

Sustainability

Force (pull)

Magnetic Field

View also deals

SMZR 32x200 / N52 - magnetic separator with handle

MW 100x30 / N38 - cylindrical magnet

MP 25x7.5/4.5x5 / N38 - ring magnet

MPL 10x10x10 / N38 - lamellar magnet

Strengths as well as weaknesses of rare earth magnets.

Benefits

Disadvantages

Lifting parameters

Maximum holding power of the magnet – what it depends on?

Practical lifting capacity: influencing factors

Precautions when working with NdFeB magnets

Do not underestimate power

Warning for allergy sufferers

Hand protection

Power loss in heat

Life threat

Dust is flammable

Keep away from electronics

Do not give to children

Magnets are brittle

Cards and drives

Physical properties of sintered neodymium magnets Nd₂Fe₁₄B at 20°C

Table 1: Static force (pull vs gap) - characteristics
MP 25x13x4 / N38

Table 2: Shear hold (wall)
MP 25x13x4 / N38

Table 3: Vertical assembly (sliding) - behavior on slippery surfaces
MP 25x13x4 / N38

Table 4: Material efficiency (saturation) - power losses
MP 25x13x4 / N38

Table 5: Thermal stability (stability) - resistance threshold
MP 25x13x4 / N38

Table 6: Magnet-Magnet interaction (repulsion) - forces in the system
MP 25x13x4 / N38

Table 7: Hazards (electronics) - precautionary measures
MP 25x13x4 / N38

Table 8: Impact energy (kinetic energy) - collision effects
MP 25x13x4 / N38

Table 9: Coating parameters (durability)
MP 25x13x4 / N38

Table 10: Construction data (P_c)
MP 25x13x4 / N38

Table 11: Physics of underwater searching
MP 25x13x4 / N38