NdFeB production and sales encountered some problems

- Nov 08, 2017 -

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(A) some problems encountered in the production

1.Oxidation

2.Cracking

3. Low density (low remanence, low energy product, can be improved by sintering)

Low coercivity (can be improved by aging)

4 missing corners

5 can not grind

6. Out of size

7. Poor coating

8 poor temperature stability


(B) sales problems encountered

1.Performance

2. Plating and coating quality (such as salt spray test)

3. Temperature coefficient

4. Processability

5. Density: N series generally in the 7.3 ~ 7.55g / cm3

H series is generally 7.4 ~ 7.6g / cm3

SH series is generally 7.48 ~ 7.62g / cm3

UH series generally 7.52 ~ 7.7g / cm3

EH series generally 7.55 ~ 7.75g / cm3

AH series is generally 7.6 ~ 7.8g / cm3

The same series of ingot material with low density, rejection with high density hydrogen density, the higher the density, the better the plating performance of the product

6. Weightlessness: The special requirements of the general can do 10mg / cm2 (100 hours or more)

7. Sintered NdFeB and bonded NdFeB: neodymium iron boron magnets is an anisotropic product, the product of high magnetic energy, and Plastic Bonded Magnets is through the adhesive to suppress the adhesive molding, is Isotropic, low energy product (5-10MGOe)

8.Patent Issues

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(C) the production of safety issues

NdFeB flammable, at the same time as anti-oxidation in the production process plus inert gas production, and therefore explosive, so important to safety, the industry in the production process of the safety issues cited

1.Smelting

A. smelting furnace products pouring due to water leakage caused by high temperature explosion caused by explosion

B. alloy ingot placed in the process of falling ground, smashed off toenails operating workers

C. rejection of argon gas furnace cleaning did not clean the staff suffocation cause of death

2. Milling: Milling appeared in the most security incidents, and many human lives

A. Airflow filtration tube explosion 

B. Stock powder burning

C. mixer explosion 

D. hydrogen broken furnace explosion 

E. Ultrafine powder burning

3. Molding

A. After mixing powder barrels have a positive pressure, improper operation of staff caused by accidents 

B. Press broken finger (NdFeB enterprises have occurred, but the installation of light control after the accident dropped)

4. Centerless grinding: grinding finger

5. Auxiliary work: the burning disk when the illegal operation of workers injured fingers (Ningbo, a business)

6. Magnetizing: magnetic products due to unidentified fingers 


(D) What is three defenses?

Anti-oxidation: As neodymium is very lively and strong affinity for oxygen, easily lead to product oxidation

Moisture-proof: the water vapor in the air has a great impact on the quality of NdFeB, if the equipment leaking products will produce ammonia taste during the process, long-term exposure of the ingot (film) has a great impact on product quality

Anti-impurities: As the various aspects of the process (especially melting, milling) lax control, the entry of dust, foreign bodies will result in scrapped a large number of products


Article from NdFeB Industry Network

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