One of the popular types of products made from NdFeB are neodymium magnets of alloy 42. These products are widely represented in the catalog of the online store https://ndfeb-magnit.ru/. Rectangles 40x40x20 mm, rods 12x25 mm, disks 70x40 mm - all these products differ in shape and size, but when marking them, the combination N42 is invariably used. What does it mean? This is a product brand that reflects a number of its technical characteristics, in particular adhesion strength and permissible operating temperature. So that you can buy an N42 neodymium magnet absolutely consciously, let’s consider the features of these and similar products.
The concept of a class of NdFeB products
Magnetic products that are offered for sale on the specialized market are divided into classes. Each of them has a set of specific technical characteristics. You can find out about them if you study the information contained on the product (applied in the form of markings). They are represented as certain combinations of letters and numeric symbols. The units of measurement for magnet characteristics are those included in the SI and SGSE (two popular measurement systems). The only exception is the indicator of the maximum permissible operating temperature, which is designated exclusively in accordance with the rules of the SI system.
The main technical characteristics of neodymium magnets are as follows:
- maximum operating temperature;
- magnetic energy;
- coercive force;
- residual magnetic induction.
Marking features
So, the most important characteristics of a magnet can be determined by its brand, which manufacturers usually mark with a letter and a number. The letter indicates the maximum temperature at which the product can be operated. For example, neodymium magnets N52 belong to the “Normal” class, which corresponds to the English letter “N” and retain their properties up to +80 0C. Such temperature conditions are sufficient in most cases of using magnetic parts, therefore such magnets are the most popular and relatively inexpensive. Next, with a gap of 20-30 degrees, come the categories “M”, “H”, “SH”, “UH” and the most resistant to high temperatures neodymium magnet, the alloy in which is called “EN”. It does not lose efficiency even at +200 0C and can be used as a component of very hot units. These are various electric motors, generators and other complex devices.
Now let's say a few words about the number in the marking, indicating the level of magnetic energy, measured in kiloJoules per cubic meter. The higher the class number, the theoretically more powerful the magnetic part. That is, simply put, neodymium magnet alloy 42 is more powerful than its “brother” grade 33 and “weaker” than products designated by the number 50.
Maximum operating temperature
When using magnetic products, it is very important to take this indicator into account. If it is exceeded during operation, the magnet may lose its original properties. You can find out which temperature range is optimal for a particular product from the letter part of its marking: N (normal - up to 80°C), M (medium - up to 100°C), H (high - up to 120°C), SH (super high - up to 150°C), UH (ultra high - up to 180°C), EH (extra high - up to 200°C).
Please note that each group is characterized by the same maximum operating temperature - regardless of the shape and size of the products. For both rectangles 20x10x5 mm and balls D25, which are marked N42, the permissible temperature is 80°C.
As for the lower temperature limit, it is common for all classes of products and is about -60°C.
Neodymium and its uses:
Neodymium, which is part of the alloy, is a chemical element located in the lanthanide group in the periodic table. It belongs to the rare earth metals. In addition to its use in the manufacture of powerful permanent magnets, it can be used as an additive to improve certain properties of structural alloys and steels, as well as for the manufacture of neodymium glasses, which use neodymium oxide, for the production of high-quality fiber optic light guides using neodymium fluoride, and for the production of thermoelectric materials using neodymium telluride.
Coercive force
This indicator is necessary to determine what the external magnetic field should be in order for a fully magnetized NdFeB product placed in it to demagnetize. The higher the number, the higher the ability of the alloy to retain residual magnetization.
Obtaining such indicators is especially important in cases where the product is operated in conditions of strong external fields, for example, in close proximity to a powerful electrical component. The units of measurement are kiloampere per meter or Oersted.
Production Highlights
It is believed that the products we describe are made from particles of three chemical elements, but few know that even N52 neodymium magnets consist of 70% iron and almost 30% boron, and they contain no more than half a kilogram of rare earth metals per ton of total mass. However, the presence of even inclusions of neodymium radically changes the properties of the alloy, affecting its attractive properties and significantly extending the service life of the product.
Much also depends on the integrity of the manufacturer. Often, products of the 35th category can be passed off, for example, as N45 neodymium magnets. Therefore, consider the sensitivity of the products and work with suppliers you trust. Remember that some companies take advantage of the fact that the exact characteristics of products can only be determined using sophisticated instruments and only after the order has been received by the client.
Thus, we can conclude that the higher the number of the product brand, the more rare earth metal it contains. N38 neodymium magnets contain a higher percentage of iron than higher grades. Such products are excellent for use at home and in some industries. At the same time, complex mechanical units will require parts with a high content of rare earth metals.
Residual magnetic induction
This indicator also relates to the power of the magnetic product - only when creating ideal conditions (closed-type magnetic system without losses and external influences). Its task is to demonstrate the flux density of field lines for a specific NdFeB ingot. The unit of measurement for remanent magnetic induction is milliTesla or kiloGauss.
For example, neodymium magnets N45 have an indicator of 1320-1380 (13.2-13.8), N50 - 1400-1450 (14.0-14.5), N42 - 1280-1320 (12.8-13.2).
The best search magnets – where they are used
A search magnet is a compact and powerful product that can attract and hold metal objects weighing tens of times its own weight. They are used to search and retrieve objects from wells, rivers and standing reservoirs.
Xhigh neodymium magnet D50x30mm – round
The review opens with a popular search magnet from Aliexpress made of neodymium. Its feature is its durable metal body. When placing an order, the user can take one of seven lot options, differing in class N35/N40/N52.
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| Brand | Xhigh |
| Form | Round |
| Dimensions | 50x30 mm |
| Price | 729-4 100 rub. |
U-Jovan – with hole
A compact hidden magnet that has many uses. For example, it can be used for magnetic locks on doors or in everyday life. The advantage of the lot is that there are many options to choose from. Up to 12 configurations are available to the user. Supplied in sets from 5 to 30 pieces. In this case, the dimensions of the products range from 8x3.3 to 20x4.5 mm.
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| Brand | U-Jovan |
| Form | Round |
| Dimensions | 8x3.3-20x4.5 mm |
| Price | 239-364 rub. |
U-Jovan D16-D60 – rescue
The TOP rescue magnet from U-Jovan continues. It is used to find lost objects in deep bodies of water. There is a rope mount on the body of the product.
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The D16-D60 was manufactured using A4 steel and 304 stainless steel, resulting in a durable unit.
| Brand | U-Jovan |
| Form | Round |
| Dimensions | D16-D60 mm |
| Price | 151-1,234 rub. |
Xiaozhufeifei Neodymium magnet – industrial
Advanced industrial magnet that can withstand temperatures up to +80 degrees. The user can select the class (up to N52) and device dimensions (up to 50x30 mm), as well as the country of shipment - Russia or China.
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| Brand | Xiaozhufeifei |
| Form | Round |
| Dimensions | 40x20-50x30 mm |
| Price | 1,111-2,576 rub. |
Hysamta 50X30MM – powerful
This is a heavy duty round magnet that is rated N35 to N52. With Hysamta you can easily lift an object over 100 kg.
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| Brand | Hysamta |
| Form | Round |
| Dimensions | 40x20-50x30 mm |
| Price | 736-1602 rub. |
U-Jovan – refrigerator magnet
Popular model from China. When ordering, you can choose both small and large holders (up to 20x3 mm). One set can contain up to 50 magnets. An excellent option for home use. For example, U-Jovan will help you attach reminders to your refrigerator.
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| Brand | U-Jovan |
| Form | Round |
| Dimensions | 4x2-20x3 mm |
| Price | 257-429 rub. |
Xhigh D74mmx28mm/D67x28mm – with bolt
The selection continues with a neodymium magnet from the Xhigh brand. This model has two holes for a bolt and a ring. The body is made in the form of a tablet.
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Xhigh is a fairly powerful magnet that can lift an object weighing up to 150 kg.
| Brand | Xhigh |
| Form | Round |
| Dimensions | 74x28 mm-67x28 mm |
| Price | 918-2 209 rub. |
N50 – set
N50 is a set of small but strong magnets made in the form of a tablet. Its diameter is 12 mm and thickness is 1 mm. The set costs only 45 rubles. For this amount, the user will receive 10 universal tablet magnets, which are suitable not only for everyday use, but also for many other purposes.
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| Form | Round |
| Dimensions | 12x1 mm |
| Price | 45 rub. |
U-Jovan 10*1 10*2 12*2 15*1 20*1 30*1mm – self-adhesive tape
This is not a simple metal magnet that we are used to. The model is made in the form of a flexible self-adhesive tape. Its width ranges from 10 to 30 mm, thickness – from 1 to 2 mm.
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Despite the fact that this tape is inferior in power to steel models, its attractive force is quite enough to find small lost objects or secure an object in the desired position.
| Brand | U-Jovan |
| Form | Round |
| Dimensions | 10x1-30x1 mm |
| Price | 185-447 rub. |
Magnet strength comparison
Using tabular values, you can determine how many times one product is more powerful than another. For example, for N50 neodymium magnets the residual magnetic induction is at least 1400 mT, and for N42 analogues - 1280 mT. Accordingly, we can say that the first product is approximately 1.09 times more powerful than the second.
It is more difficult to compare products that belong to the same class, but have different weights. In this case, it is necessary to compare the masses and express it as a percentage.
If you need to select products with certain technical characteristics, we recommend that you contact the managers of our online store for help.
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Safety precautions for handling neodymium magnets
The main advantage of neodymium magnets is their colossal magnetic force, which also poses the greatest danger in inept or careless hands. The larger the magnet, the more harm it can cause to health. Large neodymium magnets, when colliding with each other, can seriously injure limbs caught between them at that moment. The impact will be approximately the same as hitting a sledgehammer or large hammer on an anvil. You need to understand that magnets close with terrible force and this happens in an instant. Even a person experienced in handling magnets does not always have time to react and withdraw his hand at the right moment. Another unpleasant feature is that if, after being hit with a hammer, a person simply gets a bruised finger, then in the case of magnets, after the blow, this finger remains clamped between them as if in a vice, and getting it out of there is quite a difficult task. If you try to simply pull your finger out of the magnets, then with a high degree of probability they will pinch off a piece of skin from the tip of your finger or tear off your nail. To avoid such consequences, keep large neodymium magnets away from each other and from iron objects , the recommended distance is at least 1 meter. If this does happen and the hand remains pinched between the magnets, then first of all you need to insert some spacers made of non-magnetic materials - plastic or wood - between the magnets; they will prevent further closing of the magnets. After this, you can try to pull your hand out yourself or wait for the Ministry of Emergency Situations employees to arrive. Small magnets, 20-40 mm in size, can also pose a danger and, if handled carelessly, leave bruises, cuts or hematomas on the hands. It is very important to protect children from contact with neodymium magnets. Even small magnets can pose a serious threat to a child's health. Swallowing small magnets can lead to extremely negative consequences, in which case you should immediately call an ambulance. Keep neodymium magnets out of the reach of children! Large neodymium magnets create a strong magnetic field around themselves; to avoid damage, keep them away from sensitive equipment - computers, external drives, watches, smartphones, pacemakers, navigation equipment, bank cards, etc. In addition, neodymium magnets are quite fragile and can crack under strong impacts, which is also unpleasant and costly in terms of money. Always use extreme caution and caution when handling powerful magnets.
