Understanding NdFeB Grades

The number denotes a nominal energy-product class and the suffix identifies a coercivity/temperature class. Confirm the manufacturer’s guaranteed Br, Hcj and BHmax ranges and curves; the label is not an exact property row.

Mainrich’s sintered NdFeB range is N30 to N56, with no AH grades. The top grade depends on the temperature series: N56, N54M, N52H, N52SH, N50UH and N45EH. Grades up to N52SH can be made without a Chinese export licence, so we offer those first; UH and EH grades need a licence, applied for per order. Confirm the grade, suffix, geometry and production route for each drawing. This summary does not offer every combination; grades outside it in educational examples are not Mainrich supply offers.

Select the grade using the actual hot demagnetization curves, the magnetic circuit working point and the worst opposing field. A suffix is a nominal material class, not a guaranteed motor temperature limit or a chemical recipe. Do not infer alloy chemistry, price or export clearance from a suffix.

Reversible thermal loss can recover on cooling. Irreversible demagnetization can sometimes be restored by remagnetization if the material remains intact; structural degradation may be permanent. Exceeding a nominal operating rating does not alone prove microstructural destruction. Magnequench’s technical FAQ distinguishes these losses. Evaluate the cause and test the part before reuse; this is not a field-repair guarantee.

The reported N45H magnetic comparison and the separate historical 50H Dy-reduction example have different scopes. See the GBD evidence and limitations. Finished-part savings require a quotation and qualification of the proposed route.