Selecting a grade is the next step, once you have decided which permanent magnet material is best for your application. Generally, a grade indicates the Maximum Energy Product of a magnet. For instance, Grade 32 implies the (BH)max is about 32 MGOe. A higher grade of permanent magnet has a better performance. However, higher grade is usually associated with a higher cost. Taking sintered Nd-Fe-B magnets as an example, the price of Grade 45 is twice and even more of that of Grade 33. Other property parameters, such as Br and Hci, also need to be considered in selecting a grade. One way to select the suitable grade for your application is ‘trial and error’. You can purchase the several magnets with different grades (some suppliers have these magnets available on their shelves) and try each grade until you find one right for your application.
