Which magnet grade should I choose?
The grade of the magnet is an important factor that must be taken into account when deciding and choosing the magnetic product to be used in each project or application.
What is the grade of a magnet?
Neodymium magnets come in different qualities such as N42, N52 or N42SH. What does this magnet grade mean? How does the grade relate to the strength of a magnet? Does a magnet have a Gauss number?
A degree of magnetism is a measure of the strength of a magnet. In general, higher numbers indicate a stronger magnet.
The number is given by a real property of the material, the maximum energy product of the magnetic material expressed in MGOe (Mega Gauss Oersteds). It represents the strongest point in the demagnetization curve or the BH curve of the magnet.
The attraction of a magnet depends on the degree or number N. Double the number N and the traction will also double.
How do you determine the grade of a magnet or the strength of a magnet?
It depends on what is meant by force. Two common measures of the force of a magnet are the tensile force and the magnetic field force.
The traction force is the force that must be exerted on a magnet to remove it from something, for example. Like a steel surface or another magnet. The force can be given in pounds, kilograms or Newtons. The way the magnet is tested can have a big impact on the measured resistance.
There are different resistance measurements available. The force required to extract a magnet directly from a steel surface is the most commonly used. It is an excellent reference for magnetic force, expressed as a single number. Even if your application does not capture the magnet in the same way, it is often a good number to compare the strength of different magnets.
Interestingly, the tensile force between two magnets in contact is equal to the tensile force of the force described above.
Magnetic field strength is a measure of the strength and direction of the magnetic field at a given point near the magnet. It is expressed in Gauss or Tesla (1 Tesla = 10,000 Gauss). This depends on the size, shape and quality of the magnet in which the measurement is made and whether other magnets or ferromagnetic materials are present in the vicinity.
This is the important number when using magnets to activate a reed switch or a Hall effect sensor.
What grade should a magnet have?
That depends on the application. If you need the highest resistance in the smallest possible package at room temperature, the N52 magnet grade is the strongest on the market.
Many of our magnets are offered as N42 magnets, which is an excellent balance between cost, strength and performance at higher operating temperatures. With a slightly larger N42 magnet you get the same strength as with an N52 magnet.
At slightly elevated temperatures in the range of 60°C to 80°C (140°F to 176°F), the N42 magnet may be stronger than the N52. This is especially true if the shape of your magnet is very thin. More information can be found in ImagnetShop.
For even higher temperatures, consider some of our high temperature magnets offered in the N42SH class. You can find a complete list of available qualities on our Technical Data page.