SZST converted a magnet crane with a rigid boom into a conventional traversing crane, enabling both the transfer and the turning of slabs in a smooth manner. By reducing the dead weight the lifting power could be increased to 40 t. The trolley, the travelling gear and the electrical equipment were renewed and equipped with vibration absorbing devices.
The result was overwhelming for all involved. The guests attending the demonstration were enthusiastic about the new Evertz Magnet. The task was not only to transfer the slab, but to have it 'gently' turned by means of the "magnet" in a single operation. This task had never been accomplished before. Previously production used to be disrupted by frequent interruptions due to falling off slabs and the resulting heavy vibrations which could even lead to the breakdown of nearby electric stations. Moreover, the crane design required additional maintenance. All this is now a thing of the past. Impact shocks acting on the crane structure as a result of the trolley jumping the rails no longer occur. Such enormous impact shocks used to occur when during turning by conventional magnets the magnet switched from the small to the broad face, or vice versa, or when the slab fell off during turning and dashed on the floor. The resulting shocks were so heavy that they occasionally caused the trolley to jump the rails.
This task of turning and transferring 250 mm thick and up to 2,600 mm wide slabs that weigh up to 40 t in a 'gentle' manner has now been solved by the special magnet developed by Evertz-Magnetbau. The crane operator receives special instructions. The new design prevents the slabs from falling off, minimizing impacts on the crane structure. Future savings will easily amount to several millions - calculated over the lifetime of the magnet.
Taking into account the enormous lever arm of the maximum slab width (2,600 mm) and the only linear contact between the magnet and the up to 500° C hot slabs, a magnet has been developed whose magnetic field has been specifically designed for the linear contact of the poles. A key feature here is the special adjustment ratio between the poles and the slab thicknesses, which guarantees a 'gentle' turning operation.
The linear contact between the slab and the magnet also enables secure and problem-free slab transfer, both horizontally and vertically,and all this by means of only one magnet with an unloaden weight of about 10 t. The development is protected by proprietary rights. Developments are underway to use this system also with existing stripper cranes.
