Big magnet

Buyers must prioritize the Magnetic Grade (e.g., N35 to N52 for Neodymium), which determines the energy product and strength. For 'Big Magnets,' the Pull Force (measured in kg or lbs) and Magnetic Flux Density (Gauss) are essential to ensure the magnet can handle the intended load. Additionally, specify the Coating/Plating (such as Ni-Cu-Ni, Zinc, or Epoxy) to prevent oxidation, especially in humid or outdoor environments.

Standard Neodymium magnets lose magnetism above 80°C (176°F). If your application involves heat, you must source magnets with higher Coercivity (Hcj), such as SH, UH, or EH grades, which can withstand temperatures up to 200°C. Failure to match the temperature grade to the usage scenario will lead to permanent demagnetization.

Ensure the supplier provides RoHS and REACH certifications to guarantee the absence of hazardous substances. For specific industries like medical or aerospace, ISO 9001 or IATF 16949 (for automotive) quality management systems are mandatory. Furthermore, large magnets must comply with UN2807 standards regarding magnetic field leakage during air transport.

Large magnets are primarily used in Industrial Separation (removing metal contaminants), Magnetic Lifting for steel plates, Wind Turbine Generators, and MRI machines. They are also critical in Magnetic Assemblies for heavy-duty holding fixtures in construction and manufacturing.

Air transport of powerful magnets is strictly regulated. You must ensure the supplier uses Magnetic Shielding Packaging (using iron sheets and foam) so that the external magnetic field strength does not exceed 0.00525 gauss at 15 feet from the package. A Magnetic Inspection Report from a certified third-party testing body is usually required before the airline will accept the cargo.

It is common for low-quality suppliers to label N35 magnets as N52. To prevent this, request a Demagnetization Curve (Hysteresis Loop) report for the specific batch. For large orders, use Made-in-China.com's inspection services or hire a third-party auditor to perform a Gauss meter test and Pull force test during the pre-shipment inspection.

Since Neodymium magnets rely on Rare Earth elements (PrNd), prices can fluctuate weekly. Negotiate a Price Adjustment Formula based on public market indices or lock in prices with a 50% down payment to secure raw material costs immediately. For long-term contracts, seek tiered pricing based on annual volume commitments.

Large magnets pose a significant crushing hazard. Ensure the supplier includes non-magnetic spacers (wood or plastic) between units to allow for safe separation. Your warehouse staff must be trained in handling protocols, using non-magnetic tools, and keeping the products away from pacemakers, credit cards, and sensitive electronics.