Contents
NdFeB Magnet Grades Explained: A Complete Selection Guide
- Lucian.P
- Knowledge base
Introduction
From electronic devices and modern industries to new energy technologies, NdFeB permanent magnets play an essential role in many applications. When selecting neodymium magnets, the first thing engineers and buyers need to consider is the magnet grade. Choosing the right grade from a wide range of NdFeB magnet grades is a common challenge.
This article provides a detailed explanation of the NdFeB magnet grade system, helping you better understand the differences between various neodymium magnet grades and select the right magnetic solution for your application.
What Are NdFeB Magnet Grades?
NdFeB magnet grades are a standardized classification system used worldwide to define and distinguish the magnetic performance and temperature resistance of different neodymium iron boron magnets.
Simply put, a magnet grade is like the “identity card” of a magnet. It tells users two key characteristics:
- How strong is the magnet? (Maximum energy product)
- How high a temperature can it operate at? (Thermal stability limit)
A standardized grade system provides a common reference for magnetic circuit design and bulk purchasing. It is also a key foundation for ensuring stable performance and consistency in industrial products.
How to Understand NdFeB Magnet Grade Designations?
The Beginning Letter and Number: Maximum Energy Product
The first letter “N” represents Neodymium, indicating that the material is a neodymium iron boron magnet.
The following numbers, such as 35, 42, and 52, represent the material’s maximum energy product, measured in Mega Gauss Oersteds (MGOe).
A higher number means the magnet can store more magnetic energy per unit volume, resulting in stronger magnetic force and higher magnetic field strength.
The Suffix Letters: Maximum Operating Temperature Grade
As the magnet grade increases, more heavy rare earth elements such as dysprosium (Dy) and terbium (Tb) may be added to improve resistance to demagnetization. This also corresponds to different temperature resistance levels.
| Suffix | Maximum Operating Temperature |
|---|---|
| No suffix (Standard Grade) | ≤80℃ |
| M | ≤100℃ |
| H | ≤120℃ |
| SH | ≤150℃ |
| UH | ≤180℃ |
| EH | ≤200℃ |
| AH | ≥220℃ |
In practical applications, the appropriate NdFeB magnet grade should be selected according to the actual operating temperature requirements.
Different Types of NdFeB Magnet Grades
Based on performance characteristics, neodymium magnet grades can mainly be divided into standard grades and high-temperature grades.
The following table lists different NdFeB magnet grades and their performance characteristics for reference.You can check TOPMAG detailed NdFeB magnet grade information for reference.
Standard Grades (N35-N52)
Standard NdFeB magnet grades are suitable for applications under normal temperature conditions or environments with slight temperature increases.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| N35 | 1170-1220(11.7-12.2) | ≥868(≥10.9) | ≥955(≥12) | 263-287(33-36) | 80°C |
| N38 | 1220-1250(12.2-12.5) | ≥899(≥11.3) | ≥955(≥12) | 287-310(36-39) | 80°C |
| N40 | 1250-1280(12.5-12.8) | ≥907(≥11.4) | ≥955(≥12) | 302-326(38-41) | 80°C |
| N42 | 1280-1320(12.8-13.2) | ≥923(≥11.6) | ≥955(≥12) | 318-342(40-43) | 80°C |
| N45 | 1320-1360(13.2-13.6) | ≥907(≥11.4) | ≥955(≥12) | 342-366(43-46) | 80°C |
| N48 | 1360-1400(13.6-14.0) | ≥892(≥11.2) | ≥955(≥12) | 366-390(46-49) | 80°C |
| N50 | 1400-1420(14.0-14.2) | ≥836(≥10.5) | ≥955(≥12) | 382-406(48-51) | 80°C |
| N52 | 1420-1450(14.2-14.5) | ≥796(≥10) | ≥955(≥12) | 398-422(50-53) | 80°C |
| N54 | 1450-1470(14.5-14.7) | ≥796(≥10) | ≥955(≥12) | 414-438(52-55) | 80°C |
| N55 | >1470(>14.7) | ≥796(≥10) | ≥876(≥11) | 422-446(53-56) | 80°C |
High Temperature Grades (N38M and N45AH)
When the application environment involves higher operating temperatures, temperature-resistant magnet grades should be selected.
The following table shows the M Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Maximum Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 35M | 1170-1220(11.7-12.2) | ≥868(≥10.9) | ≥1114(≥14) | 263-287(33-36) | 100°C |
| 38M | 1220-1250(12.2-12.5) | ≥899(≥11.3) | ≥1114(≥14) | 287-310(36-39) | 100°C |
| 40M | 1250-1280(12.5-12.8) | ≥923(≥11.6) | ≥1114(≥14) | 302-326(38-41) | 100°C |
| 42M | 1280-1320(12.8-13.2) | ≥955(≥12.0) | ≥1114(≥14) | 318-342(40-43) | 100°C |
| 45M | 1320-1360(13.2-13.6) | ≥995(≥12.5) | ≥1114(≥14) | 342-366(43-46) | 100°C |
| 48M | 1360-1400(13.6-14.0) | ≥1027(≥12.9) | ≥1114(≥14) | 366-390(46-49) | 100°C |
| 50M | 1400-1420(14.0-14.2) | ≥1035(≥13.0) | ≥1114(≥14) | 382-406(48-51) | 100°C |
| 52M | 1420-1450(14.2-14.5) | ≥1035(≥13.0) | ≥1114(≥14) | 398-422(50-53) | 100°C |
| 54M | 1450-1470(14.5-14.7) | ≥1035(≥13.0) | ≥1114(≥14) | 414-438(52-55) | 100°C |
H Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 35H | 1170-1220(11.7-12.2) | ≥868(≥10.9) | ≥1353(≥17) | 263-287(33-36) | 120°C |
| 38H | 1220-1250(12.2-12.5) | ≥899(≥11.3) | ≥1353(≥17) | 287-310(36-39) | 120°C |
| 40H | 1250-1280(12.5-12.8) | ≥923(≥11.6) | ≥1353(≥17) | 302-326(38-41) | 120°C |
| 42H | 1280-1320(12.8-13.2) | ≥955(≥12.0) | ≥1353(≥17) | 318-342(40-43) | 120°C |
| 45H | 1320-1360(13.2-13.6) | ≥971(≥12.2) | ≥1353(≥17) | 342-366(43-46) | 120°C |
| 48H | 1360-1400(13.6-14.0) | ≥1019(≥12.8) | ≥1353(≥17) | 366-390(46-49) | 120°C |
| 50H | 1400-1420(14.0-14.2) | ≥1019(≥12.8) | ≥1353(≥17) | 382-406(48-51) | 120°C |
| 52H | 1420-1450(14.2-14.5) | ≥1019(≥12.8) | ≥1353(≥17) | 398-422(50-53) | 120°C |
| 54H | 1450-1470(14.5-14.7) | ≥1019(≥12.8) | ≥1353(≥17) | 414-438(52-55) | 120°C |
SH Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 35SH | 1170-1220(11.7-12.2) | ≥876(≥11.0) | ≥1592(≥20) | 263-287(33-36) | 150°C |
| 38SH | 1220-1250(12.2-12.5) | ≥907(≥11.4) | ≥1592(≥20) | 287-310(36-39) | 150°C |
| 40SH | 1250-1280(12.5-12.8) | ≥939(≥11.8) | ≥1592(≥20) | 302-326(38-41) | 150°C |
| 42SH | 1280-1320(12.8-13.2) | ≥971(≥12.2) | ≥1592(≥20) | 318-342(40-43) | 150°C |
| 45SH | 1320-1360(13.2-13.6) | ≥987(≥12.4) | ≥1592(≥20) | 342-366(43-46) | 150°C |
| 48SH | 1360-1400(13.6-14.0) | ≥995(≥12.5) | ≥1592(≥20) | 366-390(46-49) | 150°C |
| 50SH | 1400-1420(14.0-14.2) | ≥995(≥12.5) | ≥1592(≥20) | 382-406(48-51) | 150°C |
| 52SH | 1420-1450(14.2-14.5) | ≥987(≥12.4) | ≥1592(≥20) | 398-422(50-53) | 150°C |
| 54SH | 1450-1470(14.5-14.7) | ≥995(≥12.5) | ≥1592(≥20) | 414-438(52-55) | 150°C |
UH Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 30UH | 1080-1130(10.8-11.3) | ≥812(≥10.2) | ≥1990(≥25) | 223-247(28-31) | 180°C |
| 33UH | 1130-1170(11.3-11.7) | ≥852(≥10.7) | ≥1990(≥25) | 247-271(31-34) | 180°C |
| 35UH | 1170-1220(11.7-12.2) | ≥860(≥10.8) | ≥1990(≥25) | 263-287(33-36) | 180°C |
| 38UH | 1220-1250(12.2-12.5) | ≥876(≥11.0) | ≥1990(≥25) | 287-310(36-39) | 180°C |
| 40UH | 1250-1280(12.5-12.8) | ≥915(≥11.5) | ≥1990(≥25) | 302-326(38-41) | 180°C |
| 42UH | 1280-1320(12.8-13.2) | ≥963(≥12.1) | ≥1990(≥25) | 318-342(40-43) | 180°C |
| 45UH | 1320-1360(13.2-13.6) | ≥971(≥12.2) | ≥1990(≥25) | 342-366(43-46) | 180°C |
| 48UH | 1360-1400(13.6-14.0) | ≥987(≥12.4) | ≥1990(≥25) | 366-390(46-49) | 180°C |
| 50UH | 1400-1420(14.0-14.2) | ≥971(≥12.2) | ≥1990(≥25) | 382-406(48-51) | 180°C |
| 52UH | 1420-1450(14.2-14.5) | ≥971(≥12.2) | ≥1990(≥25) | 398-422(50-53) | 180°C |
EH Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 28EH | 1020-1080(10.2-10.8) | ≥780(≥9.8) | ≥2388(≥30) | 207-231(26-29) | 200°C |
| 30EH | 1080-1130(10.8-11.3) | ≥812(≥10.2) | ≥2388(≥30) | 223-247(28-31) | 200°C |
| 33EH | 1130-1170(11.3-11.7) | ≥836(≥10.5) | ≥2388(≥30) | 247-271(31-34) | 200°C |
| 35EH | 1170-1220(11.7-12.2) | ≥860(≥10.8) | ≥2388(≥30) | 263-287(33-36) | 200°C |
| 38EH | 1220-1250(12.2-12.5) | ≥915(≥11.5) | ≥2388(≥30) | 287-310(36-39) | 200°C |
| 40EH | 1250-1280(12.5-12.8) | ≥939(≥11.8) | ≥2388(≥30) | 302-326(38-41) | 200°C |
| 42EH | 1280-1320(12.8-13.2) | ≥955(≥12.0) | ≥2388(≥30) | 318-342(40-43) | 200°C |
| 45EH | 1320-1360(13.2-13.6) | ≥971(≥12.2) | ≥2388(≥30) | 342-366(43-46) | 200°C |
| 48EH | 1360-1400(13.6-14.0) | ≥971(≥12.2) | ≥2388(≥30) | 366-390(46-49) | 200°C |
| 50EH | 1400-1420(14.0-14.2) | ≥971(≥12.2) | ≥2388(≥30) | 382-406(48-51) | 200°C |
AH Series NdFeB Magnet Grades.
| Grade | Remanence Br mT(kGs) |
Coercivity bHc kA/m(kOe) |
Intrinsic Coercivity iHc kA/m(kOe) |
Maximum Energy Product (BH)max kJ/m³(MGOe) |
Max. Recommended Operating Temperature Tw °C |
|---|---|---|---|---|---|
| 28AH | 1020-1080(10.2-10.8) | ≥780(≥9.8) | ≥2786(≥35) | 207-231(26-29) | 230°C |
| 30AH | 1080-1130(10.8-11.3) | ≥812(≥10.2) | ≥2786(≥35) | 223-247(28-31) | 230°C |
| 33AH | 1130-1170(11.3-11.7) | ≥852(≥10.7) | ≥2786(≥35) | 247-271(31-34) | 230°C |
| 35AH | 1170-1220(11.7-12.2) | ≥876(≥11.0) | ≥2786(≥35) | 263-287(33-36) | 230°C |
| 38AH | 1220-1250(12.2-12.5) | ≥907(≥11.4) | ≥2786(≥35) | 287-310(36-39) | 230°C |
| 40AH | 1250-1280(12.5-12.8) | ≥907(≥11.4) | ≥2786(≥35) | 302-326(38-41) | 230°C |
| 42AH | 1280-1320(12.8-13.2) | ≥907(≥11.4) | ≥2786(≥35) | 318-342(40-43) | 230°C |
| 45AH | 1320-1360(13.2-13.6) | ≥907(≥11.4) | ≥2786(≥35) | 342-366(43-46) | 230°C |
How to Choose the Right NdFeB Magnet Grade for Your Application
When selecting an NdFeB magnet grade, it is necessary to consider the actual application requirements and find the most suitable balance between cost and performance.
Determine the Actual Operating Temperature
The maximum temperature generated during continuous operation of the neodymium magnet should be evaluated to prevent irreversible demagnetization.
Determine the Required Magnetic Force or Energy Product
After confirming the required temperature grade, select a magnet grade that provides sufficient magnetic performance within this range. This helps avoid unnecessary costs caused by selecting an excessively high-grade magnet.
Evaluate Demagnetization Risks in the Working Environment
If the NdFeB magnet is exposed to strong reverse magnetic fields or high-impact conditions, selecting a grade with higher coercivity can provide additional safety margins.
Conclusion
NdFeB magnet grades are an important reference when selecting neodymium magnets. They not only represent magnetic performance levels but also indicate temperature resistance and resistance to demagnetization.
Understanding and selecting the right neodymium magnet grade is essential for achieving the best balance between performance and cost. By matching the magnet grade with actual working conditions, products can achieve efficient and reliable operation throughout their service life.
Some FAQs
Do magnets with the same NdFeB grade have the same performance?
Not necessarily. Magnets with the same grade may have different performance due to variations in raw materials, manufacturing processes, and quality control.
How long can neodymium magnets maintain their magnetic performance?
Under normal conditions, high-quality neodymium magnets can maintain stable magnetic performance for a long time. However, high temperatures, corrosion, and strong magnetic fields may cause performance degradation.
How should neodymium magnets be stored?
Neodymium magnets should be stored in a dry and room-temperature environment. Avoid exposure to moisture, high temperatures, and physical impacts.
Do rare earth prices affect different NdFeB magnet grades?
Yes. Changes in raw material prices can affect the cost of NdFeB magnets, especially for high-performance and high-temperature magnet grades.
Why do high-temperature magnet grades sometimes have lower magnetic performance?
High-temperature magnet grades focus more on resistance to demagnetization and temperature stability rather than simply increasing maximum energy product.
For more insights, check these related blogs:
Magnetic Remanence Stability: Technical Principles & Applications
Ferrite Magnet Selection: A Technical Application Guide
Neodymium Magnet Selection Guide: How to Choose the Right Permanent Magnet for Your Application
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Lucian.P
Hi, I’m a technical expert at TOPMAG (10+ years in the permanent magnet industry) and author of this blog.
I’m dedicated to popularizing magnet-related content—covering principles, applications, industry anecdotes, and key tips to avoid selection pitfalls. My core goal is to provide valuable information that helps readers understand the charm and practical significance of magnets.
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