Pickling of stainless steel aims at good strip surface quality with minimized resource consumption. The SMS group’s stainless steel pickling model takes care of these requirements: In electrolytic processing of the stainless steel strip, control of current density is a major lever for reduced energy consumption and minimized carbon footprint. In sulphuric acid pre-pickling or in mixed-acid pickling, bath temperature and composition are controlled. An optimal process range, adjusted to the material requirements, is maintained.

Dosing set points are generated for all pickling liquor circuits and new acids can be used as well as sustainable regenerated acid. Removal of dissolved metal is handled by control of the waste acid flow. The short dosing cycles enable tight process windows and minimize resource consumption compared dosing based on laboratory acid measurements only.

The machine learning module automatically adapts model parameters, so that good agreement between model simulation and analyzed acid samples is established. Checks of parameterized flow rates also indicate potential clogging of pipes or pump issues.

The stainless steel pickling model can work independently or in combination with furnace control models, if pickling is performed in a combined annealing and pickling line.