GB/T 4180-2012Permanent magnetic material of rare earth cobalt (English PDF)

3.1 Primary magnetic properties

The primary magnetic properties of permanent magnetic materials include. remanence Br, magnetic flux density coercivity HcB, magnetic polarization intensity coercivity HcJ, and maximum energy product (BH) max.

Inspect the appearance and defects of the materials by visual inspection.

6.2 Dimensional tolerances, shape and position tolerances, surface roughness

The dimensional tolerance, shape and position tolerance, and surface roughness of the material shall be inspected using measuring tools that meet the metrological requirements; or inspected using special measuring tools confirmed by both the supplier and the purchaser.

6.3 Primary magnetic properties and temperature properties

c) The primary magnetic properties test methods of rare earth permanent magnetic material of rare earth cobalt shall comply with the provisions of GB/T 3217-1992.

6.3.1 Specimens

The specimens are in accordance with the provisions of GB/T 3217-1992. It is recommended to use cylindrical magnet specimens with the easy magnetization direction along the axial direction, a diameter of 8 mm~10 mm, and an aspect ratio of 0.7~1.0.

6.3.2 Magnetization of specimens

Before the test, the specimen in the initial state is magnetized under normal test atmospheric conditions to achieve magnetic saturation. The recommended minimum magnetic saturation magnetic field strength of permanent magnetic material of rare earth cobalt is shown in Table C.1 in Annex C.

6.3.3 Temperature treatment

Before measuring the temperature properties of the specimen, the magnetically saturated specimen shall be subjected to temperature cycling, that is, the specimen is heated from the starting temperature T1 to a temperature 20 K higher than the ending temperature T2 and then naturally cooled to room temperature. Keep the temperature at T1 and (T2 + 20 K) for 2 h each. This temperature cycle shall be performed at least once.

6.3.4 Primary magnetic properties

a) The specimen size shall comply with the provisions of 6.3.1;

b) Before the test, the specimen magnetization shall comply with the provisions of 6.3.2;

6.3.5 Temperature properties

6.3.5.1 Measurement principle

In the Helmholtz coil, the permanent magnet specimen is regarded as a magnetic dipole. Therefore, the induced electromotive force generated by the permanent magnet

d) After the flux integrator is reset, the computer outputs the rotation command to rotate the sample 180° around the Y axis;

e) The computer records the data of the flux integrator at this time, that is, the flux value of the specimen at temperature T1, that is, 2 Phi(T1);

f) According to steps b) to e), measure the flux value 2 Phi(T2) at temperature T2;

g) According to formula (5), calculate the magnetic moment temperature coefficient of the sample;

h) The test report shall at least provide the following information.

- Specimen number;

- Specimen material designation;

- Specimen shape and size;

- Measuring device;

- Measurement temperature range;

- alpha m;

- Signature of the tester and auditor;

- Test date.

7.1 Inspection and acceptance

7.1.1 The supplier's quality supervision department shall inspect the materials to ensure that they comply with the requirements of this Standard and provide a quality certificate.

7.1.2 The purchaser shall conduct acceptance inspection on the received materials in accordance with the provisions of this Standard. If the acceptance inspection results do not conform to the provisions of this Standard, the purchaser shall submit the unqualified samples to the supplier within one month from the date of receipt of the product, and then the supplier and the purchaser shall negotiate to resolve the issue. If arbitration is required, it may be entrusted to a unit recognized by both parties, and the supplier and the purchaser shall jointly take samples.

7.2 Batching

Each batch of materials shall consist of materials of the same designation, specifications and dimensions made by the same production process.

7.3 Inspection items

The inspection items for each batch of materials include the following items. The increase or decrease of items can be negotiated by the supplier and the purchaser.

- Appearance and defects;

- Dimensions and tolerances;

- Shape and position tolerances;

- Surface roughness of processed surfaces;

- Primary magnetic properties;

- Temperature properties;

- Quality;

- Other inspection items specified in the contract.

7.4 Sampling plans

The sampling plans for each batch of materials are.

a) The sampling plan for appearance and defects shall be in accordance with the normal inspection sampling plan of GB/T 2828.1-2003, general inspection level

b) The sampling plan for dimensions and tolerances shall be in accordance with the normal inspection sampling plan of GB/T 2828.1-2003, general inspection level

c) The sampling plan for shape and position tolerances shall be in accordance with the normal inspection sampling plan of GB/T2828.1-2003, special inspection level S2, AQL=1.5;

d) The sampling plan for surface roughness of machined surfaces shall be in accordance with the normal inspection sampling plan of GB/T 2828.1-2003, special inspection level S2, AQL=1.5;

e) The sampling plan for primary magnetic properties shall be in accordance with the normal inspection sampling plan of GB/T 2828.1-2003, special inspection level S2, AQL=1.5;

f) For the measurement of temperature properties, at least 3 pieces shall be randomly sampled from each batch;

g) All quality items shall be measured;

h) Other inspection items specified in the contract shall be based on the agreed sampling plan.

7.5 Qualification determination

According to the sampling plan of 7.4 and the test method of Chapter 6, each batch of materials shall be inspected for the items specified in 7.3. If the requirements of 5.1 ~ 5.3 are met, the batch of materials shall be qualified. If the materials fail to pass the sampling plan in the normal inspection, double samples shall be taken from the batch of materials for re-inspection of the unqualified items. If they still fail to pass, the batch of materials shall be judged as unqualified.

8.1 Marking and packaging

8.1.1 Materials are generally delivered in a magnetically neutral state and the orientation direction is marked. If magnetization is required, this shall be noted in the contract in advance.

8.1.2 Materials shall be packed in boxes and ensured not to be damaged during transportation and storage. The packaging of magnetized materials shall comply with relevant regulations. Each inner box shall be labeled with.

- Supplier name;

- Material name;

- Designation;

- Batch number;

- Specification and size;

- Net mass;

- Date of manufacture.

8.2 Transportation and storage

The materials shall be handled with care during transportation to ensure that they are not damaged. The materials shall be stored in a ventilated, dry place with no corrosive atmosphere.

8.3 Quality certificate

A quality certificate shall be attached to each batch of materials when they are delivered. […]