So, what exactly is a lifting magnet? A lifting magnet or magnet lifter as they may be from time to time known as is a piece of lifting gear that is suitable for lifting ferro-magnetic materials such as mild steel. Steel is manufactured from a mixture of several metals, producing an alloy; the main ones being iron, nickel and manganese, these substances and their compounds are ferro- magnetic . But particular varieties of stainless-steel will not be magnetic as a result of their make up. Metals with different make-ups possess different capabilities to carry magnetism, so for materials other than mild steel (which the next few paragraphs mostly refers too) such as; high carbon steels, forged iron and ferrous alloys a reduction in the lifting capacity should be applied, this varies between the materials, so always refer to the lifting magnet handbook.
Lifting ferro-magnetic metals is made easy by using a lifting magnet or 2 and can lift cubic or cylindrical shapes, however they really are mainly used for lifting large sheets of mild steel and so regularly found in steel foundries and workshops, although are also utilised in scrap and ship yards. When used for lifting cylindrical objects, owing to their smaller contact zone the magnet will have a lowered lifting capacity.
Lifting Magnet can be found in a variety of models with varying capacities, all which will possess a minimum thickness of steel which they are able to lift safely, utilising magnet to lift steel with less than the stated minimum will have a great impact on the safety of the lift. Different versions are designed for lifting varying lengths of sheet steel, but more than 1 lifting magnet can be utilized over the same piece allowing for extended lengths to be lifted, this technique is a common practice in steel plants, however if more than 1 magnet is to be utilised then you must use a spreader beam with a magnet at each end, these permit both magnets to be raised at the same time to keep the load stable
It is very important to be aware of things that could have an impact on the lifting capacity and therefore safety of the magnet. Air gaps are the most common hindrance; these are usually brought on by poorly machined steel surfaces, dust or dirt and paint; the surface needs to be as smooth and clean as achievable to avoid these air gaps because the more air gaps present the lower the safe lifting capacity of the magnet and so may possibly cause the magnet to release the load. The magnet needs to have full and total connection with the steel to achieve maximum lifting capacity. Trial lifts should always be undertaken to evaluate the hold and stability of the load, this enables re-positioning if needed.
Lifting magnets are a simple to operate and very cost efficient way of lifting ferro-magnetic materials since they require no power and little maintenance, keeping it very spotless is crucial, however you should have them tested and inspected by an authorised individual at least every 12 months to ensure their continuous safety.
The guidelines for utilising a magnet lifter safely are many, the major one being not to use by medical equipment, pacemakers or insulin pumps because the magnet could hinder their function. You must also never lock the lever down without a load fitted (locking the lever down magnetises the lifter) and also never raise the lever or de-magnetise until the load is securely and completely lowered.