Billet Magnets

These are among the essential equipment for steel mills. Both electro permanent magnets and electromagnets can be used for billet lifting applications. Thanks to specially developed resins, billets with core temperatures up to 600 °C can be handled safely.

They are used initially for transporting the billets from cooling bed which is after tundish at steel mills. After this stage, these magnets are used for stockpiling of billets, loading them on the vehicles and transporting them to furnace feeding units of rolling mills. Electropermanent magnetic systems are designed with a safety factor of 3. Whereas for electomagnetic systems the safety factor is minimum 2 (Relevant Standard: UNI EN 13155: 2003 + A2: 2009 Lifting Appliances - Safety - Non-fixed load lifters). To illustrate, an electromagnetic system to lift :7 nos of 150x150mm, 12m-long billets with a total weight of 15 tons is designed based on a minimum load of 30 tons.

Electropermanent magnetic systems are ideal solutions for billet lifting applications as they operate with a "zero drop" principle. These systems do not drop the load even in case of power failures or damaged magnet cables and just need to initially grab the load. Additionally, these systems do not have backup battery units and hence no maintenance is required. Neodymium or samarium cobalt is used inside these magnets. Having many advantages, electropermanent magnets are costlier than electromagnets.

Due to cost advantage and availability of adding many functions to the systems, electromagnetic systems are commonly preferred for billet lifting applications. Such systems have backup battery units to prevent dropping of load in case of a power failure.

Things to Consider When Choosing Billet Magnets

• Where the magnet is to be used (Cooling bed, stockpiling, vehicle loading, stock yard, etc.),
• Crane lifting capacity,
• Number, cross section, minimum and maximum lengths of billets to be lifted at once
• Maximum temperature of billets

(Electropermanent magnetic systems systems can be used to lift billets with core temperatures up to 600 °C. As they start losing magnetic properties beyond this temperature which makes it impossible for the magnet to catch)