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sales@tujinmagnet.com
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+86-18858010843
The NdFeB Ring Magnet with Countersunk is in the shape of a ring with a circular hole in the middle, which is convenient for users to perform various connection and fixing operations. Its unique highlight is that the outer edge of the magnet is designed with a circular groove, which is the so-called "countersunk". This design not only improves the beauty of the magnet, but also shows extremely high practicality in practical applications. The circular hole in the middle provides users with a variety of connection methods, such as fixing by ropes, chains or other ring structures, which increases the flexibility of use. The unique countersunk design takes the practicality of this magnet to a new level. It allows users to firmly install it in the desired position with screws or other fasteners, whether it is a flat or curved surface, to achieve perfect fit and fixation.
The color of NdFeB Ring Magnet with Countersunk is silver or gray, with a smooth and shiny surface, showing a high-quality metal texture. This not only makes it more conspicuous in various application scenarios, but also effectively resists corrosion and oxidation, extending its service life.
When manufacturing NdFeB Ring Magnet with Countersunk, we use advanced production processes and strict quality control standards to ensure that each magnet can achieve the best quality performance. From the purchase of raw materials to every link of the production process, we have carried out strict screening and testing to ensure the stability and reliability of the final product.
Products show

Surface Coating & Corrosoin Resistance
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| Nickel(Ni-Cu-Ni) | Zinc(Zn) | Black Epoxy | Gold |
| Type | Color | Plating Thickness | Working Temperature |
Advantage & Suitable | Salt Spray Resistance | |||||
| Nickel(NiCuNi) | silver | 20-30 um | ≤200 | high oxidation resistance, good glossiness, stable performance, long service life | > 72 hrs | |||||
| Zinc (Zn) | blue white | 10-20 um | ≤160 | suitable for low requirements for surface appearance & oxidation resistance | > 48 hrs | |||||
| Epoxy | black | 10-30 um | ≤120 | suitable for high anti-corrosion and strict atmospheric environment | > 96 hrs | |||||
| Gold | Gold | 5-30 um | ≤200 | suitable for decoration accessories, gift box etc. | > 24 hrs | |||||
Tolerance

| Standard Product | D.OD | ID | L | W | H |
| <5mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm |
| <10mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm |
| <20mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm |
| <50mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm | ±0.1mm |
| <100mm | ±0.15mm | ±0.15mm | ±0.15mm | ±0.15mm | ±0.15mm |
| >100mm | ±0.2mm | ±0.2mm | ±0.2mm | ±0.2mm | ±0.2mm |
Magnetization Direction
| Disc&Cylinder-through Thickness | Disc&Cylinder-through Diameter | Spheres- through Diameter |
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Poles on the flat surfaces
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Poles on the side surfaces |
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| Block- through Thickness | Block- through Length | Arc- through Diamter |
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Poles on the larger flat surfaces |
Poles on the smaller flat surfaces |
Poles on outside&inside faces |
| Arc- through Length | Ring- through Surfaces | Ring- through Surfaces |
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Poles on outside&inside faces |
Planar octupole magnetization |
Planar quadrupole magnetization |
Sintered NdFeB Magnetic Properties
| Grade | Remanence | Coercive Force | Intrinsic Coercivity | Maximum Energy | Working≤ | |||||||
| Br(KG) | Br(T) | Hcb (KOe) |
Hcb (KA/m) |
Hcj (KOe) |
Hcj (KA/m) |
(BH)max(MGOe) | (BH)max (KJ/ m) |
℃ | ||||
| Max | Min | Max | Min | |||||||||
| N35 | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥12 | ≥960 | 37 | 33 | 295 | 263 | N | ≤80 |
| N38 | ≥12.3 | ≥1.23 | ≥10.8 | ≥860 | ≥12 | ≥960 | 39 | 36 | 310 | 287 | ||
| N40 | ≥12.7 | ≥1.27 | ≥11.0 | ≥876 | ≥12 | ≥960 | 41 | 38 | 327 | 302 | ||
| N42 | ≥13.0 | ≥1.30 | ≥11.0 | ≥876 | ≥12 | ≥960 | 43 | 40 | 343 | 320 | ||
| N45 | ≥13.3 | ≥1.33 | ≥11.0 | ≥876 | ≥12 | ≥960 | 46 | 42 | 366 | 335 | ||
| N48 | ≥13.7 | ≥1.37 | ≥10.5 | ≥836 | ≥12 | ≥960 | 49 | 45 | 390 | 358 | ||
| N50 | ≥14.0 | ≥1.40 | ≥10.5 | ≥836 | ≥12 | ≥960 | 51 | 47 | 406 | 374 | ||
| N52 | ≥14.2 | ≥1.42 | ≥10.5 | ≥836 | ≥12 | ≥960 | 53 | 49 | 422 | 390 | ||
| N54 | ≥14.4 | ≥1.44 | ≥10.5 | ≥836 | ≥11 | ≥876 | 55 | 51 | 438 | 406 | ||
| N35M | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥14 | ≥1114 | 37 | 33 | 295 | 263 | M | ≤100 |
| N38M | ≥12.3 | ≥1.23 | ≥11.0 | ≥876 | ≥14 | ≥1114 | 39 | 36 | 310 | 287 | ||
| N40M | ≥12.7 | ≥1.27 | ≥11.5 | ≥915 | ≥14 | ≥1114 | 41 | 38 | 327 | 302 | ||
| N42M | ≥13.0 | ≥1.30 | ≥11.8 | ≥939 | ≥14 | ≥1114 | 43 | 40 | 343 | 320 | ||
| N45M | ≥13.3 | ≥1.33 | ≥12.0 | ≥956 | ≥14 | ≥1114 | 46 | 42 | 366 | 335 | ||
| N48M | ≥13.7 | ≥1.37 | ≥12.2 | ≥972 | ≥14 | ≥1114 | 49 | 45 | 390 | 358 | ||
| N50M | ≥14.0 | ≥1.40 | ≥12.5 | ≥995 | ≥14 | ≥1114 | 51 | 47 | 406 | 374 | ||
| N52M | ≥14.2 | ≥1.42 | ≥12.5 | ≥995 | ≥14 | ≥1114 | 53 | 49 | 422 | 390 | ||
| N33H | ≥11.4 | ≥1.14 | ≥10.6 | ≥844 | ≥17 | ≥1350 | 35 | 31 | 279 | 247 | H | ≤120 |
| N35H | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥17 | ≥1350 | 37 | 33 | 295 | 263 | ||
| N38H | ≥12.3 | ≥1.23 | ≥11.0 | ≥876 | ≥17 | ≥1350 | 39 | 36 | 310 | 287 | ||
| N40H | ≥12.7 | ≥1.27 | ≥11.5 | ≥916 | ≥17 | ≥1350 | 41 | 38 | 327 | 302 | ||
| N42H | ≥13.0 | ≥1.30 | ≥11.8 | ≥940 | ≥17 | ≥1350 | 43 | 40 | 343 | 320 | ||
| N45H | ≥13.3 | ≥1.33 | ≥12.0 | ≥955 | ≥17 | ≥1350 | 46 | 42 | 366 | 335 | ||
| N48H | ≥13.6 | ≥1.36 | ≥12.2 | ≥971 | ≥17 | ≥1350 | 49 | 45 | 390 | 358 | ||
| N50H | ≥14 | ≥1.4 | ≥12.5 | ≥995 | ≥17 | ≥1350 | 51 | 47 | 406 | 374 | ||
| N52H | ≥14.3 | ≥1.43 | ≥12.5 | ≥995 | ≥17 | ≥1350 | 53 | 49 | 422 | 390 | ||
| N33SH | ≥11.4 | ≥1.14 | ≥10.6 | ≥844 | ≥20 | ≥1592 | 35 | 31 | 279 | 247 | SH | ≤150 |
| N35SH | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥20 | ≥1592 | 37 | 33 | 295 | 263 | ||
| N38SH | ≥12.3 | ≥1.23 | ≥11.0 | ≥876 | ≥20 | ≥1592 | 39 | 36 | 310 | 287 | ||
| N40SH | ≥12.6 | ≥1.26 | ≥11.5 | ≥916 | ≥20 | ≥1592 | 41 | 38 | 327 | 302 | ||
| N42SH | ≥12.9 | ≥1.29 | ≥11.8 | ≥940 | ≥20 | ≥1592 | 43 | 40 | 343 | 320 | ||
| N45SH | ≥13.2 | ≥1.32 | ≥12.0 | ≥955 | ≥20 | ≥1592 | 46 | 42 | 366 | 335 | ||
| N48SH | ≥13.6 | ≥1.36 | ≥12.2 | ≥971 | ≥20 | ≥1592 | 49 | 45 | 390 | 358 | ||
| N50SH | ≥14 | ≥1.4 | ≥12.5 | ≥995 | ≥20 | ≥1592 | 51 | 47 | 406 | 374 | ||
| N33UH | ≥11.4 | ≥1.14 | ≥10.6 | ≥844 | ≥25 | ≥1990 | 35 | 31 | 279 | 247 | UH | ≤180 |
| N35UH | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥25 | ≥1990 | 37 | 33 | 295 | 263 | ||
| N38UH | ≥12.3 | ≥1.23 | ≥11.0 | ≥876 | ≥25 | ≥1990 | 39 | 36 | 310 | 287 | ||
| N40UH | ≥12.6 | ≥1.26 | ≥11.5 | ≥916 | ≥25 | ≥1990 | 41 | 38 | 327 | 302 | ||
| N42UH | ≥12.9 | ≥1.29 | ≥11.8 | ≥940 | ≥25 | ≥1990 | 43 | 40 | 343 | 320 | ||
| N45UH | ≥13.2 | ≥1.32 | ≥12.0 | ≥955 | ≥25 | ≥1990 | 46 | 42 | 366 | 335 | ||
| N48UH | ≥13.6 | ≥1.36 | ≥12.2 | ≥971 | ≥25 | ≥1990 | 49 | 45 | 390 | 358 | ||
| N28EH | ≥10.4 | ≥1.04 | ≥9.50 | ≥756 | ≥30 | ≥2388 | 30 | 26 | 239 | 207 | EH | ≤200 |
| N30EH | ≥10.8 | ≥1.08 | ≥9.50 | ≥756 | ≥30 | ≥2388 | 32 | 28 | 255 | 223 | ||
| N33EH | ≥11.4 | ≥1.14 | ≥10.6 | ≥844 | ≥30 | ≥2388 | 35 | 31 | 279 | 247 | ||
| N35EH | ≥11.8 | ≥1.18 | ≥10.8 | ≥860 | ≥30 | ≥2388 | 37 | 33 | 295 | 263 | ||
| N38EH | ≥12.3 | ≥1.23 | ≥11.0 | ≥876 | ≥30 | ≥2388 | 39 | 36 | 310 | 287 | ||
| N40EH | ≥12.6 | ≥1.26 | ≥11.5 | ≥916 | ≥30 | ≥2388 | 41 | 38 | 327 | 302 | ||
| N42EH | ≥12.9 | ≥1.29 | ≥11.8 | ≥940 | ≥30 | ≥2388 | 43 | 41 | 343 | 320 | ||
| N45EH | ≥13.2 | ≥1.32 | ≥12.0 | ≥955 | ≥30 | ≥2388 | 46 | 42 | 366 | 335 | ||
| N30TH | ≥10.8 | ≥1.08 | ≥9.50 | ≥756 | ≥35 | ≥2786 | 32 | 28 | 255 | 223 | TH | ≤220 |
| N33TH | ≥11.4 | ≥1.14 | ≥10.6 | ≥844 | ≥35 | ≥2786 | 35 | 31 | 279 | 247 | ||
| N35TH | ≥11.8 | ≥1.18 | ≥11.0 | ≥876 | ≥35 | ≥2786 | 37 | 33 | 295 | 263 | ||
| N38TH | ≥12.2 | ≥1.22 | ≥11.0 | ≥876 | ≥33 | ≥2627 | 39 | 36 | 310 | 287 | ||
| Remarks: The maximum working temperature depends on the shape, size, and coating of the magnet, the highest working temperature in the table is the test data for standard sample. | ||||||||||||
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