Thin Steel Plate lifting with magnets
In our more than a decade of experience in design and supply of magnetic lifting equipment for various types of steel material handling, we have continued and still continue to encounter a great deal of misconception amongst intending users of magnetic lifting devices. Today, Lifting magnets are available in a wide range of shapes and designs but all of these are usually catered for a specific shape of steel material to be handled. The criteria which are usually significant in magnet lifting equipment design are the steel material dimensions, material surface quality, material temperature, and steel material contact area with the magnetic device.
However, one of the greatest misconceptions is usually centered around thin steel plate handling. We have lost count of the number of times we have needed to address this concern as an obligatory education exercise we undertake with all our new customers. Often we receive inquiries for our popular permanent magnet manual handle lifters but we make it a point to verify what these will be used for. And often the answer is "to handle steel plates". Well, we don't have a problem with that, but we do have a problem when the steel plate is usually long & thin enough to cause a bending of the edges in an arc shape enough to cause a 'peeling' effect on the intended single unit of magnetic lifter. Lets say, a 26' x 8' steel plate of 0.5" thickness (or 8 Mtr x 2.4 Mtr x 13mm) weighing about 2 Tons should not be attempted to be lifted by a single unit of a 2 Ton Permanent Magnet lifter such as below, placed at the centre of the plate. When the overhang from the magnetic lifter to the edge of the steel plate is 2000mm (6.5') or more, this plate will bend at the edges during lifting and eventually peel off, causing danger to personnel and equipment.
Instead, the same plate should be lifted with a distributed arrangement of multiple smaller capacity lifters such as 4 units of 500 Kg capacity (instead of a single unit of 2000 Kg), suspended from a spreader beam, such as shown below. The objective is to prevent the bending of the edge of the plate and confining the overhang of the steel plate to within 1500 mm (5') or less.
Of course, the ideal arrangement for handling such large and thin plates will be to deploy the Electro Permanent Magnet range of magnetic lifting spreader beams from which can be operated from a distance by a single operator. But then, that is another story.