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Sheet coils

Sheet coils when produced are handled internally in steel mills, stored in logistic warehouses and shipped to end customers to be processed to products. Along such process chains, coil magnets from TRUNINGER are widely used. Many decades of experience in coil magnet design combined with our controller's highest safety standards created a striking alternative to mechanical lifting gear.

 

Applications

Sheet coils require specific lifting magnets, for cold-rolled, hot-rolled or slit coils different solutions are applied.
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Cold-rolled sheet coil handling

Transporting coils gently

Steel mills, logistics companies and service centres set high standards in terms of coil quality. Such quality must be maintained for all transport processes weather in house or outside the company. No pressure marks, damaged edges or residual magnetism are tolerated.

An excellent alternative to mechanical lifting devices, such as tongs or C-hooks, are electro magnets. TRUNINGER produces special magnets for cold-rolled sheet coils weighing up to 50 tons. Each of these magnets can handle a wide range of different coil diameters and widths.
 

Figure 1: Cold-rolled sheet coils in stock area
 

Coil magnets grip the coil peripheral from above and do not touch the eye such as tongs or lifters. Damages of the coil eye or side faces are thus absent.

TRUNINGER coil magnets are also equipped with proximity sensors as standard. These sensors allow the magnet to be set down gently on the coil. 

Using a magnet system yields the following benefits:
 

Your advantages

  • Fast picking and placing, easy handling
  • Increased storage density of up to 30% due to elimination of aisles
  • No pressure marks or edge damages
  • Increased safety thanks to deep magnetic field
  • Quick and thorough demagnetisation
  • Minimum maintenance (no moving parts)
 

Your benefits

  • Significant time savings
  • You can store considerably more material within the same area
  • No degradation in coil quality
  • No problem handling packed coils
  • Complete removal of residual magnetism
 



Figure 2: Densely stored coils in a warehouse

Handling of hot-rolled coils

Reliable and safe

Every day steel mills and logistic companies handle huge volumes of hot-rolled coils either internally as semi-finished products or externally as sales products. TRUNINGER coil magnets enable quick, safe and reliable handling, as well as loading and unloading of lorries, railway wagons and ships.
 

Figure 1: Magnetic coil transport applied to ships and railway wagons
 

In contrast to cold-rolled coils, hot-rolled coils are not tightly wound due to contraction of the material in the cooling process. Air gaps formed in-between the windings of steel significantly reduce the magnet’s lifting force (see figure 3); the larger the air gaps the greater the impact on the lifting force. For safety reasons this loss of lifting force needs to be compensated.

Coil magnets with deeply-penetrating magnetic field have been developed to match hot-rolled coil properties.

At TRUNINGER for dimensioning and design of such magnets FE method is applied. Finite element simulation helps to optimise existing magnet designs and to develop new, client-specific magnet solutions.
 

Your advantages

  • Fast picking and placing of coils as well as easy handling
  • Small overall height of magnets allows higher coil stacks
  • No damage of coil surface or edges
  • Hot-rolled coils securely held despite of air gaps
  • Fast and thorough demagnetisation
 

Your benefits

  • High speed, significant time savings
  • You can store considerably more material within the same area
  • Complete removal of residual magnetism
  • Excellent integration into automated warehouse systems
 
TRUNINGER design features
  • Coil magnets can be equipped with two independent magnet coils each of them being powered and monitored separately by the magnet controller.
  • Should one electric circuit fail, the remaining circuit will continue to carry the load. The controller generates a visual and audible alarm and sends a signal to the crane. When this happens, the load must be set down and the magnet switched off (see ‘Fully redundant system’).
     

Figure 2: Moving a hot-rolled coil — note the air gap!
 

  • Using signals from proximity sensors mounted between the magnet poles the crane control system is able to reduce the approach speed of the hoist. This allows to guarantee soft touch down of the magnet on the coil.
     

Figure 3: Carrying hot-rolled coils in a outdoor stock yard
 

  • Special design magnets equipped with temperature-resistant magnet coils guarantee a long service life also when used to carry hot coils in harsh environments.

Slit coil handling

Transport of coated, sensitive coils

In rolling mills red-hot slabs get rolled down to a final thickness of 1 to 18 mm and sent on as hot-rolled sheet coils for further processing. Cold-rolled products are also present in thicknesses of under 1mm. Depending on the size ordered by the customer, coils get slit lengthways to form narrower strips, known as slit strips. Slitting the coils in this way produces numerous coil sizes and thicknesses.
 

Figure 1: Slitting the coil lengthways to form slit strip rings
 

Slit coils are also zinc-plated, galvanised or painted. The slit coils get further processed into finished products in the metalworking industry, e.g. in forming and diecutting operations or in tube manufacturing.

No matter what needs to be done, there is always a TRUNINGER magnet for the job, e.g.:

  • Lifting a slit coil pack
  • Carrying individual slit coils
     

Figure 2: Stacking a vertical slit coil in a tube manufacturer’s warehouse
 

Using an electromagnet is an alternative to using purely mechanical lifting devices, e.g. a chook. For production reasons in steel mills or slitting plants the entire pack of slit coils gets carried away and placed into storage in one lift (see figure 3).

Carrying slit coils magnetically requires a powerful magnet with a deep field penetration in order to ensure that the necessary force is applied to the narrow coil width for a safe and secure transport.
 

Figure 3: Handling a pack of slit coils in one lift
 

TRUNINGER magnet system yield the following advantages and benefits:
 

Your advantages

  • Coils or complete slit packs can be quickly picked up and set down
  • Easy handling, no need for mechanical lifting devices
  • More compact storage, no aisles and wooden spacers required
  • Coils handled with care, no damage to edges or surfaces
  • Delicate handling of thin and coated slit coils
  • Direct feeding of machines
 

Your benefits

  • Significant time saving
  • Fewer accidents and increased safety
  • You can store considerably more slit coils within the same area
  • No degradation in coil quality
  • No operating assistants required, lower personnel costs
 

 

Special application: Slit coil tilting device

Depending on the type of handling equipment, slit coils may be delivered either:

  • Eye-up, axis vertical
  • Standing upright, axis horizontal

However, subsequent processing of slit coils often requires to rotate from  horizontal to vertical position or vice versa. For this purpose, TRUNINGER has developed a slit coil magnetic tilting device (see ‘Coil rotator’ and figure 4).
 

Figure 4: Coil tilting device with ring magnet 

Features

  • Coil tilting magnets allow to turn & transport simultaneously
  • Horizontal alignment of the coils
  • Heat resistant magnets allow handling of coils up to 600°C
  • Total redundancy for maximum safety
  • Safe handling of packed or coated coils
  • Almost complete removal of residual magnetism (< 2mT)

Gallery

Lifting magnet systems for sheet coils by TRUNINGER AG

Further fields of application

Beams and profiles

Beams and profiles

Space-efficient beam storage

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Plates

Plates

Handling plates safely and storing them efficiently

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Scrap

Scrap

Solutions for robust, powerful and safe operation

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Billets, slabs and beam blanks

Billets, slabs and beam blanks

Handling billets, slabs, and beam blanks safely

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Rebars

Rebars

Increase productivity—one-man rebar handling

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Round bars

Round bars

Moving and placing round bars efficiently

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Merchant bars

Merchant bars

Handling and moving merchant bars intelligently and safely

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Tubes

Tubes

Stacking tubes up to six meters without any spacers in-between

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Sheet coils

Sheet coils

Handling sheet coils reliably without any damage

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Sheets

Sheets

Separating sheets gently and moving them with ease

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