| Demo : Aluminium Sheet |
Description
During hot rolling a complex coating of aluminium, lubricant products and aluminium oxide builds up on the rolls and despite the use of roll brushes to minimize the build up of this "roll coating" it is inevitable that the occasional transfer of small particles of this coating takes place to the slab. This debris on the surface is called "hot mill pick up" and is most noticeable if the product is anodized at reroll gauge.
Why is it important ?
Visual appearance of the sheet is an important quality attribute, although product performance may not be unduly compromised.
How is it measured ?
Samples are taken at reroll gauge, anodised to highlight the pick-up and then visually inspected. The images below show anodized samples of reroll showing various degrees of hot mill pick up.
1.5
2.0
2.5