Excellent aluminum coil coating line for aluminium coil

with foil rolls, rcuring furnace, etc.

As aluminium is supplied cold rolled, it is usually supplied unlevelled (unlike steel which is often levelled in the galvanising line before colour coating), . It is therefore common to see tension levelling in the continuous process sections of aluminium coil coating lines. This avoids marking due to stopping / starting of the strip in the levelling machine and ensures optimum surface flatness and condition prior to coating

Once again due to aluminium’s surface sensitivity and the soft alloys a 6 high levelling roll cassette is required.

This design avoids any ‘tram-lining’, a marking problem that can be seen on the strip (and potentially through the colour coated product) created by back up rolls contacting the works rolls, which is eliminated by use of the 6 high machine design by the addition of intermediate rolls.

Strip Cleaning (Cleaning Sections) and Pre-treatment

In general, cleaning sections for steel and aluminium are similar if not the same in construction. Aluminium is usually supplied oiled but often this is dry and easily removable with alkali based cleaner. Many older aluminium coil coating lines were set up with only one tank, however, an additional tank combined with hot rinses and a well-designed cascade system can both limit water consumption and volume of effluent requiring water treatment prior to disposal. The major difference in an aluminium cleaning seciton is the absence of a brush scrubber that is more typically required for cleaning steel.

Today, many pre-treatment chemicals are universal for both steel and aluminium and a move to chrome free products is being driven by environmental legislation. The use of roll coaters can allow for improved chemical application, reducing chemical consumption and provides a more accurate coating. With both roll coating and spray / squeegee systems dry-in-place chemicals are preferred today. This avoids any post rinsing again reducing effuent levels from the line and environmental impact.