UMH 25x8x45 [M5] / N38 - magnetic holder with hook
magnetic holder with hook
Catalog no 310426
GTIN: 5906301814559
Diameter Ø [±0,1 mm]
25 mm
Height [±0,1 mm]
45 mm
Height [±0,1 mm]
8 mm
Weight
33 g
Magnetization Direction
↑ axial
Load capacity
25 kg / 245.17 N
Coating
[NiCuNi] nickel
14.49 ZŁ with VAT / pcs + price for transport
11.78 ZŁ net + 23% VAT / pcs
bulk discounts:
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Magnetic properties of material N38
Physical properties of sintered neodymium magnets Nd2Fe14B at 20°C
Shopping tips
Strengths and weaknesses of neodymium magnets.
In addition to their long-term stability, neodymium magnets provide the following advantages:
- They do not lose magnetism, even over around ten years – the drop in strength is only ~1% (theoretically),
- Magnets effectively protect themselves against demagnetization caused by foreign field sources,
- A magnet with a metallic nickel surface is more attractive,
- Magnetic induction on the working layer of the magnet is extremely intense,
- Neodymium magnets are characterized by extremely high magnetic induction on the magnet surface and can function (depending on the form) even at a temperature of 230°C or more...
- Thanks to versatility in constructing and the capacity to modify to complex applications,
- Huge importance in future technologies – they are used in magnetic memories, brushless drives, diagnostic systems, as well as multitasking production systems.
- Thanks to concentrated force, small magnets offer high operating force, with minimal size,
Disadvantages of NdFeB magnets:
- They are fragile upon too strong impacts. To avoid cracks, it is worth securing magnets in a protective case. Such protection not only shields the magnet but also increases its resistance to damage
- Neodymium magnets decrease their strength under the influence of heating. As soon as 80°C is exceeded, many of them start losing their power. Therefore, we recommend our special magnets marked [AH], which maintain durability even at temperatures up to 230°C
- Due to the susceptibility of magnets to corrosion in a humid environment, we recommend using waterproof magnets made of rubber, plastic or other material resistant to moisture, when using outdoors
- We suggest casing - magnetic mechanism, due to difficulties in producing nuts inside the magnet and complex forms.
- Potential hazard to health – tiny shards of magnets pose a threat, if swallowed, which becomes key in the aspect of protecting the youngest. Furthermore, tiny parts of these magnets are able to disrupt the diagnostic process 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
Best holding force of the magnet in ideal parameters – what affects it?
The force parameter is a theoretical maximum value conducted under specific, ideal conditions:
- using a base made of high-permeability steel, acting as a ideal flux conductor
- possessing a thickness of minimum 10 mm to ensure full flux closure
- characterized by smoothness
- under conditions of ideal adhesion (metal-to-metal)
- for force acting at a right angle (pull-off, not shear)
- at standard ambient temperature
Magnet lifting force in use – key factors
During everyday use, the actual holding force is determined by several key aspects, ranked from crucial:
- Clearance – existence of foreign body (rust, tape, gap) acts as an insulator, which reduces capacity steeply (even by 50% at 0.5 mm).
- Loading method – declared lifting capacity refers to detachment vertically. When attempting to slide, the magnet holds significantly lower power (often approx. 20-30% of maximum force).
- Base massiveness – insufficiently thick plate causes magnetic saturation, causing part of the flux to be lost into the air.
- Steel grade – the best choice is pure iron steel. Cast iron may generate lower lifting capacity.
- Smoothness – full contact is obtained only on smooth steel. Rough texture reduce the real contact area, reducing force.
- Thermal conditions – neodymium magnets have a negative temperature coefficient. At higher temperatures they lose power, and in frost they can be stronger (up to a certain limit).
* Lifting capacity was determined using a polished steel plate of suitable thickness (min. 20 mm), under perpendicular pulling force, in contrast under shearing force the holding force is lower. In addition, even a small distance {between} the magnet’s surface and the plate decreases the lifting capacity.
H&S for magnets
Threat to navigation
A strong magnetic field disrupts the functioning of magnetometers in smartphones and navigation systems. Do not bring magnets near a smartphone to avoid damaging the sensors.
Do not underestimate power
Use magnets with awareness. Their huge power can shock even professionals. Be vigilant and respect their power.
Nickel allergy
Medical facts indicate that the nickel plating (standard magnet coating) is a potent allergen. If you have an allergy, avoid direct skin contact or choose encased magnets.
Fire risk
Mechanical processing of neodymium magnets poses a fire hazard. Neodymium dust oxidizes rapidly with oxygen and is hard to extinguish.
Bone fractures
Risk of injury: The pulling power is so great that it can cause blood blisters, crushing, and even bone fractures. Use thick gloves.
ICD Warning
Warning for patients: Powerful magnets disrupt medical devices. Maintain minimum 30 cm distance or request help to work with the magnets.
Power loss in heat
Monitor thermal conditions. Exposing the magnet above 80 degrees Celsius will permanently weaken its magnetic structure and pulling force.
Adults only
Strictly store magnets away from children. Choking hazard is high, and the effects of magnets clamping inside the body are tragic.
Electronic hazard
Equipment safety: Strong magnets can damage payment cards and sensitive devices (pacemakers, medical aids, mechanical watches).
Risk of cracking
NdFeB magnets are sintered ceramics, meaning they are fragile like glass. Impact of two magnets leads to them cracking into shards.
Danger!
More info about hazards in the article: Safety of working with magnets.
