MP 20x8/4x5 / N38 - ring magnet
ring magnet
Catalog no 030333
GTIN: 5906301812272
Diameter [±0,1 mm]
20 mm
internal diameter Ø [±0,1 mm]
8/4 mm
Height [±0,1 mm]
5 mm
Weight
16.49 g
Magnetization Direction
↑ axial
Load capacity
1.71 kg / 16.77 N
Magnetic Induction
296.67 mT
Coating
[NiCuNi] nickel
7.75 ZŁ with VAT / pcs + price for transport
6.30 ZŁ net + 23% VAT / pcs
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MP 20x8/4x5 / N38 - ring magnet
Magnetic properties of material N38
Physical properties of NdFeB
Shopping tips
Advantages and disadvantages of neodymium magnets NdFeB.
In addition to their pulling strength, neodymium magnets provide the following advantages:
- They have constant strength, and over more than 10 years their performance decreases symbolically – ~1% (according to theory),
- They remain magnetized despite exposure to magnetic surroundings,
- By applying a shiny layer of silver, the element gains a clean look,
- The outer field strength of the magnet shows advanced magnetic properties,
- Thanks to their enhanced temperature resistance, they can operate (depending on the shape) even at temperatures up to 230°C or more,
- With the option for tailored forming and personalized design, these magnets can be produced in numerous shapes and sizes, greatly improving engineering flexibility,
- Important function in new technology industries – they find application in hard drives, rotating machines, medical equipment along with technologically developed systems,
- Compactness – despite their small size, they generate strong force, making them ideal for precision applications
Disadvantages of neodymium magnets:
- They can break when subjected to a powerful impact. If the magnets are exposed to mechanical hits, it is advisable to use in a steel housing. The steel housing, in the form of a holder, protects the magnet from cracks , and at the same time reinforces its overall strength,
- They lose power at increased temperatures. Most neodymium magnets experience permanent reduction in strength when heated above 80°C (depending on the form and height). However, we offer special variants with high temperature resistance that can operate up to 230°C or higher,
- Magnets exposed to wet conditions can corrode. Therefore, for outdoor applications, it's best to use waterproof types made of rubber,
- Limited ability to create internal holes in the magnet – the use of a external casing is recommended,
- Potential hazard from tiny pieces may arise, especially if swallowed, which is crucial in the context of child safety. Furthermore, miniature parts from these devices might hinder health screening once in the system,
- High unit cost – neodymium magnets are pricier than other types of magnets (e.g., ferrite), which may limit large-scale applications
Maximum lifting force for a neodymium magnet – what contributes to it?
The given lifting capacity of the magnet represents the maximum lifting force, measured under optimal conditions, that is:
- with mild steel, serving as a magnetic flux conductor
- of a thickness of at least 10 mm
- with a polished side
- in conditions of no clearance
- with vertical force applied
- in normal thermal conditions
Key elements affecting lifting force
Practical lifting force is determined by factors, by priority:
- Air gap between the magnet and the plate, because even a very small distance (e.g. 0.5 mm) causes a drop in lifting force of up to 50%.
- Direction of applied force, because the maximum lifting capacity is achieved under perpendicular application. The force required to slide the magnet along the plate is usually several times lower.
- Thickness of the plate, as a plate that is too thin causes part of the magnetic flux not to be used and to remain wasted in the air.
- Material of the plate, because higher carbon content lowers holding force, while higher iron content increases it. The best choice is steel with high magnetic permeability and high saturation induction.
- Surface of the plate, because the more smooth and polished it is, the better the contact and consequently the greater the magnetic saturation.
- Operating temperature, since all permanent magnets have a negative temperature coefficient. This means that at high temperatures they are weaker, while at sub-zero temperatures they become slightly stronger.
* Holding force was checked on the plate surface of 20 mm thickness, when the force acted perpendicularly, however under attempts to slide the magnet the lifting capacity is smaller. Moreover, even a slight gap {between} the magnet’s surface and the plate lowers the load capacity.
Handle Neodymium Magnets with Caution
Neodymium magnets should not be near people with pacemakers.
Neodymium magnets generate very strong magnetic fields that can interfere with the operation of a pacemaker. This is because many of these devices are equipped with a function that deactivates the device in a magnetic field.
The magnet coating contains nickel, so be cautious if you have a nickel allergy.
Studies show a small percentage of people have allergies to certain metals, including nickel. An allergic reaction often manifests as skin redness and rash. If you have a nickel allergy, try wearing gloves or avoid direct contact with nickel-plated neodymium magnets.
Neodymium magnets are over 10 times more powerful than ferrite magnets (the ones in speakers), and their power can shock you.
Please review the information on how to handle neodymium magnets and avoid significant harm to your body, as well as prevent unintentional damage to the magnets.
Dust and powder from neodymium magnets are highly flammable.
Do not attempt to drill into neodymium magnets. Mechanical processing is also not recommended. Once crushed into fine powder or dust, this material becomes highly flammable.
Neodymium magnets can become demagnetized at high temperatures.
Despite the general resilience of magnets, their ability to retain their magnetic strength can be influenced by factors like the type of material used, the magnet's shape, and the intended purpose for which it is employed.
Magnets should not be treated as toys. Therefore, it is not recommended for children to have access to them.
Remember that neodymium magnets are not toys. Do not allow children to play with them. Small magnets can pose a serious choking hazard. If multiple magnets are swallowed, they can attract to each other through the intestinal walls, causing significant injuries, and even death.
Magnets made of neodymium are highly susceptible to damage, resulting in their cracking.
Neodymium magnets are characterized by significant fragility. Magnets made of neodymium are made of metal and coated with a shiny nickel, but they are not as durable as steel. At the moment of connection between the magnets, sharp metal fragments can be dispersed in different directions.
You should maintain neodymium magnets at a safe distance from the wallet, computer, and TV.
The strong magnetic field generated by neodymium magnets can damage magnetic media such as floppy disks, video tapes, HDDs, credit cards, magnetic ID cards, cassette tapes, etc. devices. They can also damage devices like video players, televisions, CRT computer monitors. Do not forget to keep neodymium magnets away from these electronic devices.
Neodymium Magnets can attract to each other, pinch the skin, and cause significant injuries.
If have a finger between or on the path of attracting magnets, there may be a large cut or a fracture.
Do not bring neodymium magnets close to GPS and smartphones.
Intense magnetic fields generated by neodymium magnets interfere with compasses and magnetometers used in navigation, as well as internal compasses of smartphones and GPS devices.
Be careful!
Please see the article - What danger lies in neodymium magnets? You will learn how to handle them properly.