Electro Tinning / Tin Free Steel

Tinning line is the most complex and sophisticated strip processing line containing in sequence the following processes: Dip Cleaning, Electrolytic Cleaning, Pickling, TFS plating (1^st & 2^nd steps + rinse + drag out), Tin Plating (+ rinse/dragout + flux), tin Reflow, Chemical treatment and oiling. Modern lines have included also the side trimming and the tension levelling.

In the most advanced lines the tin plating is performed with the technology of insoluble anodes where the dissolution of tin is carried out in special plants where Tenova was able to solve the big problem of the high generation of sludge. The high amount of sludge had afflicted the previous lines but with the Tenova technology of tin dissolution the generation of sludge is at the same rate of the lines with tin soluble anodes.

For particular applications, the tin plate can be replaced by Tin Free Steel (TFS) or ECCS (Electrolytic Chromium Coated Steel). TFS can be produced either in the same tinning line (with dedicated additional plating tanks), or in a separate line in case of high productions. Tenova supplies both High Technology Tinning and TFS lines (Single or Combined).

Conventional  Chemical Treatment  (ASTM # 300 or 311) using Hexavalent Chromium, due to concern of occupational health and safety  will be  shortly  not more permitted in  Europe and over the world. Tenova supplies equipment for alternative Cr-Free passivation.Tenova has developed a new low-sludge tin dissolution process for the insoluble anode technology. The application of this technology minimizes the amount of sludge produced and hence the loss of tin.

Other benefits of Tenova’s insoluble anodes process are the reduction of manpower for anode handling and therefore increase in safety during operation, improved coating quality, better process control, more flexible campaigns and the lowest tin coating thickness reachable on the strip.

Insoluble anodes are of a fixed width. In order to process strips of different widths edge masks are used to prevent "white border defects".

Tenova’s edge mask design guarantees easy inspection and access to the cell for maintenance and operational activities.

Tenova is developing its own process know how for the Cr-Free passivation to be in condition to deal properly with the customers needing Cr-Free passivation for revamping of existing  lines or  for new lines.

With the proper coater developed internally and a proper drying system Tenova supplies Titanium/Zirconium Cr free passivation sections to produce passivated products named 505 and 555 as per EN 10202  in the last revision draft.