Principle, Technology

Texturing of metal sheet

The roughness of the metal sheet is an important, quality-related product characteristic when manufacturing metal sheet in the cold rolling mill. It influences significantly the tribological forming behaviour of the sheet and is a decisive basis for the paint adherence as well as the optical appearance of the colour.

The required surface structure of the metal sheet is generated in the roll stand. The surface of the work roll is structured by different methods. During the rolling process the surface roughness is partly transferred to the metal sheet.
Texturing of metal sheet in the rolling mill
  1. TOPOCROM® coated work rolls
  2. Texturing of the metal sheet surface
TOPOCROM® structure on the roller surface
The embossed structure on the metal sheet surface

Topocrom® coated work rolls

The most favourable sheet characteristics are achieved with Topocrom® coated work rolls. In addition to the excellent tribological and optical properties on the metal sheet extremely long service life is reached. The work rolls are used in the skin pass mill as well as in a tandem mill.
Schematic illustration of the texturing process in the rolling mill. Above and below the TOPOCROM® coated work rolls are shown; in between the metal sheet with the indentations in the surface.

Topocrom® coating in closed reactors

The Topocrom® coating of the work rolls is effected in a closed reactor. Thus it is guaranteed that no gases with Cr6 particles pollute the environment. The Topocrom® technology is wastewater-free and has been industrially proved for many years.

Properties of the Topocrom® surface on work rolls

  • Adjustable surface topographies in wide ranges
  • Adjustable roughness and peak accounts
  • Stochastic surface structure avoid moiré effects
  • High hardness of the Topocrom® functional surface
  • Convex surface structures
  • Schedule free rolling with work rolls possible
Equipment for the coating of work rolls in steel works. The picture shows the removal of a roll from the coating reactor.

Properties of the PRETEX and POSTEX metal sheet surface

  • Distinctive, isolated, stochastically divided lubrication pockets
  • Adjustable quantity of finely divided dome-shaped lubrication pockets
  • Adjustable roughness values and peak accounts
  • Low roughness values together with high peak accounts possible
  • Due to the evenness of the structure no filler is necessary for the painting (Volkswagen Process Specification TL 218 of May 2012)
  • Low long and short-waviness on the metal sheet surface
  • Even roughness structure also with long roll transport ways.

For further information about the plant technology, please contact:

Topocrom Systems AG

Gewerbestrasse 8, 8212 Neuhausen am Rheinfall / Switzerland
Telephone 0041 (0)71 620 01 83,
Managing Director: Karl Müll, Commercial register No. CH-020.3.928.924-8