Pickling is the first step in the production process of cold-rolled strip. First, the coils from the hot strip mill are welded into endless strips. In the continuous pickling line the scale that forms on the hot strip during hot rolling is rinsed with hydrochloric acid. This creates a bare metallic strip surface.
To ensure an uninterrupted pickling process, the continuous pickling line features a strip accumulator, also called a looper. The strip is accumulated to avoid unintentional standstill or operational stops, e.g. for coil welding.