China Neodymium And Ferrite Magnets Manufacturer & Supplier 
18mm neodymium magnets are a relatively standard size, and customers can choose the appropriate shape according to their product needs, such as 18mm round, 18mm ring, or 18mm block. To help you understand its Gauss and pull strength, we have compiled some data for your reference.
The accompanying image shows the size of an 18mm diameter circular neodymium magnet.
The magnetic flux density of 18 mm neodymium magnets is mainly affected by their grade (such as N35, N42, N54) and volume. As the grade of the magnet increases, so does the magnetic flux density.
For example: 18x2.5mm round neodymium magnet, with a surface magnetic field strength ranging from approximately 2000 to 2700 Gauss and a pull force of about 2 kg. For example. 18mm x 5mm round neodymium magnet, with a surface magnetic strength of over 4000 Gauss and a pulling force of approximately 3 kg.
Let's take a look at the 18mm block neodymium magnet, 18x3x3mm, with a surface magnetic flux density of approximately 3400 Gauss and a pulling force of approximately 1.3kg. 18x3x4mm, with a surface magnetic flux density of approximately 3500 Gauss and a pulling force of approximately 1.6kg.
Finally, there is an 18mm ring shaped neodymium magnet with an outer diameter of 18mm, hole 7mm, thickness 6mm, a surface magnetic flux density of approximately 3600 Gauss, and a pulling force of approximately 3.5 kg.
It should be noted that the magnetic flux density of 18 mm neodymium magnets is mainly affected by their grade (such as N35, N38, N42, N54), volume, and magnetization direction. With the same dimensions, as the magnet grade increases, the magnetic flux density also increases, as does the pulling force.
"How much can be sucked" is not the same as “pull force.” Pull force is the force required for separation, and theoretically, it can hold objects lighter than this weight. However, in practical applications, due to factors such as vibration, impact, and uneven contact, the safe load should be much less than this maximum value.
If the steel plate has paint, rust, unevenness, or the object being sucked is thin, the actual pull force will be significantly reduced.
The above is an introduction to the surface magnetism and pull force of 18mm neodymium magnets. If you require extremely high surface magnetism, you should choose a higher grade (such as N54) or thicker magnets (such as 18x8mm or 18x10mm).
Related 18mm neodymium magnet samples;
18mm dia flat round magnet ndfeb 2140 gauss Φ18 x 2 mm