How to classify bearing grades

The accuracy of bearings is mainly divided into dimensional accuracy and rotational accuracy. The accuracy level has been standardized and divided into five levels: P0, P6, 

P5, P4, and P2.

The accuracy increases sequentially from level 0. For general purposes, level 0 is sufficient, but for special conditions or occasions, level 5 or higher accuracy is required.

Former Chinese bearing code, accuracy level code。The standards formulated by various countries are based on ISO standards, generally consistent with ISO standards, 

and some are stricter than ISO standards. Accuracy is divided into dimensional accuracy and rotational accuracy. It is divided into levels 0, 6X, 6, 5, 4, and 2.

The old code standards for Chinese bearings used to be: G level (0 level), E level (6 level), D level (5 level), C level (4 level), and B level (2 level). The current code generally 

adopts the German DIN standard.

P0 level (level 0), P6 level (level 6), P5 level (level 5), P4 level (level 4), P2 level (level 2).The general standard grade P0 is omitted in the bearing model, and the grade code 

only appears in the bearing model for P6 or above.

For example: 6205 and 6205/P5, where the accuracy level of 6205 is P0, but it is omitted. This creates the impression that P0 level bearings are not precision level bearings.

In addition, bearings with various accuracies differ not only in their processing technology, but also in their value.