What is Magnet Grade?

Magnet grade is the Arabic numerals followed permanent magnet material. For example: N42 of sintered ndfeb magnet, BNP10 of bonded neodymium magnet, 30H of smco 2:17, alnico5, ferrite Y30 or PA6 of injection molding ferrite. It is a measure of magnet strength. Generally, higher number indicates stronger as well as more expensive.

If you look at these grade charts closely, you will find a rule. The rule is that most of these grades, no matter for neodymium magnet or smco, their number are closely to their maximum energy product. That’s because magnet grades are based on maximum energy product, which relates to the magnetic flux output per unit volume.

Click below picture for more about different material grade

How to distinguish maximum working temperature of different grades in sintered neodymium magnets table?

There are some suffix letters following the grade such as M, H or SH. These indicate maximum working temperatures (we use celsius temperature), which range from M (up to 100 °C) to AH (220 °C).

The grade without suffix letter has maximum operating temperature 80°C, however N52 & N55 (the highest grade) only work at 60°C.

The working temperature for other materials is not as many as sintered neodymium magnet, so there is no suffix letter to mark, such alnico magnets, all can work at high temperatures 550°C.

Although magnet grade is a good measure of the strength of a magnet, we can’t use it to measure the strength of a magnet in reality.

How can I measure the magnet strength?

There are two common measures of a magnet’s strength: one is the pull force and the other is the strength of the magnetic field.

Pull strength is a very subjective measure. The professional tensioner is a necessary tool for measuring tension in the magnet industry. Other testing methods may lead to very different results. And the pull force is usually not very accurate as it depends on many external factors such as:

The magnetic field strength is a measurement of the magnetic field’s strength. You can test it by gauss meter on the surface of N and S poles and while testing, make sure there is no presence of any other magnets or ferromagnetic materials nearby.

For magnet manufacturer, instead of magnetic field strength, magnetic flow is the most accurate measuring standard for judging whether the magnet qualified.

How to select the materials and grades of rare earth magnets?

When customers don’t know what magnet to use, we will provide suggestion. Our suggestion depends on application and specific size.

If you use magnet on room temperature, neodymium magnet is best. With small magnet size and low grade, it gets strongest power than other material.

The magnet size can be smaller compared with N35 magnet if you use N52 magnet.

If you need strong magnet with max working temp 300 centigrade, samarium cobalt magnet is the right choice.

When you use magnet on a car starting dynamo or similar structure, you have to use neodymium magnet in SH series or above.

Keep in mind that the higher the grade the more brittle the magnets will be while selecting a grade.

Make sure you will not reach or exceed the max value, or the magnets will be damaged while selecting a grade based on working temperature.

China Magnets Source Material has the ability to produce magnets in a variety of materials and grades that can be applied to all applications. Please feel free to contact us if you have any question for choosing a material or grade.