Understanding Neodymium Magnets and Why Grade Matters

With so many different types of magnets to choose from, when are neodymium magnets the right option? Sintered neodymium magnets are extremely popular for applications requiring strong magnetic fields in a compact size, but the choice of magnet grade depends on the specific needs of each application. In this guide, we’ll cover:

• What are neodymium magnets?
• Neodymium magnet grade chart
• Comparison and common uses of neodymium magnet grades
• Factors to consider when choosing a neodymium magnet grade 

The difference between permanent magnets, such as neodymium magnets, and electromagnets, is simple. Permanent magnets produce a consistent magnetic field of their own, whereas electromagnets need help from an external source.

Neodymium magnets (or ndfeb magnets) are known for their exceptional strength, with the ability to lift things many times more than their weight. Neodymium magnets are typically compact in size and possess a strong magnetic field. Different neodymium magnet grades are used in everything from electronics to industrial equipment. 

Safety considerations for neodymium magnets

Respect neodymium magnets’ strength. The strong magnetic force between these magnets can create hazards if mishandled. When neodymium magnets larger than a few cubic centimetres are brought into proximity to each other, they can press together with considerable force. Anything – or anyone – in the way can suffer injuries. It’s paramount that strong neodymium magnets are carefully and meticulously handled.  

Neodymium magnet grade chart

Neodymium magnets (or ndfeb magnets) are classified into different grades based on their magnetic properties. These grades provide information about the strength and performance of the Neodymium magnets. The grades are typically designated by a combination of letters and numbers. The most commonly used grading system for neodymium magnets is the N-rating system. 

Let’s take this example: N42SH

N42SH is a designation that provides information about the characteristics of a neodymium magnet. This alphanumeric code provides details about the magnet's grade, maximum energy product, and temperature resistance. 

• N: This stands for Neodymium, indicating that the magnet is made primarily from neodymium.
• Number: The number 42 following the "N" represents the maximum energy product (BHmax) of the magnet, which is a measure of its strength. A higher number indicates a stronger magnet. In this case, "42" indicates a relatively strong magnet with a high magnetic flux density. 
• Letters: The letters following the number indicates the temperature rating of the magnet. In our example, SH signifies that the magnet has a super high temperature resistance. Different letters correspond to different temperature ranges, as you’ll see in the chart below. 

Here's a breakdown of the different grades and their characteristics:

Grade	Characteristic
N	Standard-temperature rating of approximately 80°C (176°F). Neodymium magnets in this grade are suitable for general-purpose applications.
M	Medium-temperature rating, around 100°C (212°F). These magnets offer slightly better temperature resistance compared to the N-grade magnets.
H	Represents a high-temperature rating, typically around 120°C (248°F) and are suitable for applications that involve higher operating temperatures.
SH	Represents super high-temperature resistance, usually around 150°C (302°F). Designed for applications where higher temperatures are a concern.
UH	Represents ultra-high-temperature resistance, approximately 180°C (356°F). Ideal for applications where both high strength and high-temperature performance are required.
EH	Represents extremely high temperature resistance, around 200°C (392°F). Used in applications that involve even higher temperatures.
AH	Represents the highest temperature resistance available, with a rating of around 220°C (428°F). Specifically designed for extreme high-temperature applications.

 

Magnet grades: neodymium

Our standard range of neodymium magnets include N42 and N38 grades. If you’re interested in other grades, please contact us.

For your convenience, we’ve listed all grades of these magnets in the table below.

N Grade	Residual Induction   Br (KG)	Coercive force HcB (KOe)	Intrinsic Coercive force Hci (kOe)	Max. energy Product BHmax (MGOe)	Max. operating temperature TW
35	1170–1220 (11.7–12.2)	≥ 868 (≥ 10.9)	≥ 955 (≥ 12)	263-287 (33-36)	80 °C
38	1220–1250 (12.2–12.5)	> 899 (≥ 11.3)	≥ 955 (≥ 12)	287-310 (36-39)	80 °C
40	1250–1280 (12.5–12.8)	≥ 907 (≥ 11.4)	≥ 955 (≥ 12)	318-342 (40-43)	80 °C
42	1280–1320 (12.8–13.2)	≥ 915 (≥ 11.5)	≥ 955 (≥ 12)	318-342 (40-43)	80 °C
45	1320–1380 (13.2–13.8)	> 923 (≥ 11.6)	≥ 955 (≥ 12)	342-366 (43-46)	80 °C
48	1380-1420 (13.8-14.2)	≥ 796 (≥ 10.0)	≥ 876 (≥ 11)	382-406 (48-51)	80 °C
50	1400–1450 (14.0–14.5)	≥ 796 (≥ 10.0)	≥ 876 (≥ 11)	382-406 (48-51)	80 °C
52	1430–1480 (14.3–14.8)	> 796 ( ≥ 10.0)	≥ 876 (2 11)	398-422 (50-53)	80 °C
33M	1130–1170 (11.3–11.7)	≥ 836 (≥ 10.5)	≥ 1114 (≥ 14)	247-263 (31-33)	100 °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 (2 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	1320-1380 (13.2-13.8)	> 995 (≥ 12.5)	> 1114 (≥14)	342-366 (43-46)	100 °C
48M	1360-1430 (13.6-14.3)	≥ 1027 ( ≥ 12.9)	> 1114 (≥ 14)	366-390 (46-49)	100 °C
50M	1400-1450 (14.0-14.5)	> 1033 (≥ 13.0)	≥ 1114 (≥ 14)	382-406 (48-51)	100 °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)	> 963 (≥ 12.1)	> 1353 (≥17)	347-366 (43-46)	120 °C
48H	1370-1430 (13.7-14.3)	> 995 (≥ 12.5)	> 1353 (≥17)	366-300 (46-49)	120 °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	1240-1280 (12.5-12.8)	≥ 939 (≥ 11.8)	≥ 1592 (≥ 20)	302-326 (38-41)	150 °C
45SH	1320-1380 (13.2-13.8)	≥ 1003 (≥ 12.6)	≥ 1592 ( ≥ 20)	342-366 (43-46)	150 °C
28UH	1020-1080 (10.2-10.8)	≥ 764 (≥9.6)	≥ 1990 (≥25)	207-231 (26-29)	180 °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)	≥ 860 (≥ 10.8)	≥ 1990 (≥ 25)	247-271 (31-34)	180 °C
35UH	1180-1220 (11.8-12.2)	≥ 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	1240-1280 (12.5-12.8)	≥ 899 (≥ 11.3)	≥ 1990 (≥ 25)	302-326 (38-41)	180 °C
28EH	1040-1090 (10.4-10.9)	≥ 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)	≥ 876 (> 10.5)	≥ 2388 (≥ 30)	223-247 (28-31)	200 °C
35EH	1170-1220 (11.7-12.2)	≥ 876 (≥ 11.0)	≥ 2388 (≥ 30)	263-287 (33-36)	200 °C
38EH	1220-1250 (12.2-12.5)	≥ 899 (≥ 11.3)	> 2388 (≥ 30)	263-287 (33-36)	200 °C
28AH	1040-1090 (10.4-10.9)	≥ 787 (≥ 9.9)	≥ 2624 (≥33)	207-231 (26-29)	230 °C
30AH	1080-1130 (10 8-11.3)	≥ 819 (> 10.3)	≥ 2624 (> 33)	223-247 (28-31)	230 °C
33AH	1130-1170 (11.3-11.7)	≥ 843 (≥ 10.6)	> 2624 (> 33)	247-271 (31-34)	230 °C

Comparison and common uses of neodymium magnet grades

Let’s compare different grades of magnets to help you better understand the neodymium magnet grade chart. You’ll also see how each of the grades in our magnet strength chart are typically used. Not all have industrial uses, but it’s worth showing their applications to give you a clearer picture of that grade’s strength. 

N35-N52 (Standard Grades, up to 80°C)

These magnet variants are commonly found in everyday applications due to their versatility and affordability. Frequently used for:

• Small electronic devices like headphones and speakers
• Magnetic catches, such as door latches
• DIY projects and crafts

N30M-N50M (Medium Temperature-Resistant Magnets, up to 100°C)

Can withstand slightly higher temperatures, making them suitable for applications that need enhanced temperature resistance. Often used in:

• Electric motors for household appliances
• Generators and alternators
• Automotive sensors and switches

N30H-N48H (High-Temperature-Resistant Magnets, up to 120°C)

With the ability to endure higher temperatures, these magnets are ideal for demanding applications, such as:

• Industrial electric motors and generators
• High-temperature sensors and switches
• Equipment in the oil and gas industry

N30SH-N45SH (Super-High-Temperature-Resistant Magnets, up to 150°C)

Engineered for extreme conditions, and used in specialised fields such as:

• Components for aerospace and aviation
• Automotive turbochargers
• High-performance electric motors and generators

28AH-33AH (Ultra-High-Temperature-Resistant Magnets, up to 230°C)

These grades are tailored for applications that need exceptional temperature resistance. They’re commonly used in:

• High-temperature manufacturing processes
• Automotive under-the-hood components
• Specialised industrial machinery and equipment

View our range of neodymium magnets

Factors to consider when choosing a neodymium magnet grade

When making a decision about the right neodymium magnet grade for your application, you’ll need to take into account several critical factors. This will ensure that your magnet performs effectively and maintains its durability over time. 

• Magnetic Strength: Determine the precise level of magnetic strength that your application needs. The grade you use should align with the desired magnetic pull force required
• Temperature Resistance: What is the expected temperature range that will affect the magnet? Use a grade that can stand up to those temperatures without experiencing a significant loss of magnetic properties. 
• Size and Shape: The physical dimensions and shape of the magnet can affect its magnetic performance. Different grades may exhibit varying magnetic properties based on their unique dimensions. Larger neodymium magnets generally have stronger magnetic fields compared to smaller ones of the same grade. The shape affects how the magnetic field is distributed around it. Irregular or complex shapes might lead to variations in field strength across different parts of the magnet's surface. Uniform shapes, such as rectangles or cylinders, tend to have more consistent magnetic field distributions.
• Environmental Conditions: Think about the environment that the magnet will be exposed to. Factors such as humidity, potential corrosion, and exposure to chemicals should be considered. Choose neodymium magnets with coatings that protect against degradation. Nickel is an excellent coating. Zinc is another popular choice.
• Demagnetisation Risk: Certain neodymium magnet grades are more susceptible to demagnetization due to external magnetic fields or elevated temperatures.If necessary, opt for a grade that minimises the risk of demagnetization in your specific application. 
  • Grades with higher Hci values are better suited to resist demagnetisation. High-coercivity grades include N48H, N50H, N52H, N30SH, N33SH, N35SH, N38SH, N40SH, N42SH, and N45SH. Ultra-high coercivity grades include N28UH, N30UH, N33UH, N35UH, and N38UH. Others with higher coercivity grades fall under the EH category. 
• Application Type: If your application involves vibrations, impacts, or extreme conditions, use a specific grade that offers enhanced durability. Compare your application to those listed in the previous section to get an idea of what grade you should use. 
• Size-to-Strength Ratio: Think about the trade-off between size and strength. In some cases, a lower-strength grade with larger dimensions might be more suitable for your application than a smaller, higher-strength grade. To determine the ratio you need, divide the required pull force by the available space or dimensions. This will give you an initial idea of the strength you need per unit of space.
• Manufacturability: Decide how the neodymium magnet will be integrated into your design. Certain grades could be more challenging to handle, machine, or assemble due to their stronger magnetic properties.

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