The influence of batch annealing parameters on the gas-metal reaction in close-set coils
In order to improve the corrosion resistance of phosphated and painted panels, the car body industry requires clean steel sheets, without residual surface carbon pollution. The present study concerns the elimination of rolling oils residues during batch annealing treatments. By means of gas phase analysis during the annealing treatment and of sheet surface characterisation using techniques such as SIMS, XPS, it was possible to get a better understanding of the gas-metal reactions which occur at high temperature. This involves reactions between the steel substrate, the pollution film coming from former operations (pickling residues, rolling emulsion) and the protective atmosphere. A rolling oil residues elimination mechanism is proposed. It is shown that the surface cleanliness can be improved not only by optimisation of cold rolling conditions but also by modifications of batch annealing parameters. It is verified that the main effect of this practice is to decrease the level of annealed pollution but also to change its nature, giving some residual carbon which is more easily removed during later processing.
Bibliographic Reference: EUR 12115 FR (1989) MF, 137 pp., ECU 8, blow-up copy ECU 17.50
Record Number: 198910723 / Last updated on: 1994-12-01
Original language: fr
Available languages: fr