core sector communique

SMS SIEMAG

Shougang Jingtang orders two electrolytic tinning lines

Shougang Jingtang (Shougang Jingtang United Iron & Steel), China, has requested SMS Siemag. Germany, to erect two electrolytic tinning lines for the annual production of altogether 475,500 t of high quality tinplate. The lines are used for protecting ultra-thin sheet against corrosion by applying a thin layer of tin. The sheet is then used as packaging material. Shougang Jingtang decided in favor of a line with soluble anodes, not least because of the low tin consumption. Both lines are to be put into operation at the end of 2013 on Caofedian Island, an artificially constructed island, off the coast of the Chinese province of Hebei.

The lines have identical equipment and each has two pay-off reels in the entry section, followed by a welder and a trimming shear as well as by a vertical strip accumulator. The process section commences with an electrolytic cleaning section, a tension, leveler and an electrolytic pickling section. The tin layer is then applied in a total of nine vertical coating cells.

Downstream of the strip dryer is a reflow unit, in which the coating is heated inductively to above the melting point of the tin, thus providing the strip with a shiny surface and forming an alloy layer which enhances the corrosion protection and the adhesion of the tin layer. This is followed by a passivation unit with a dryer. The exit section contains another vertical strip accumulator, an inspection stand, a flying shear and two tension reels.

With an annual production of 237,500 t each, both lines will be used for providing the materials T1 to T5 (single reduction)  and DR7 to DR10  (double reduction) with tin coatings between 700 and 1,280 mm, and it is possible to process strip gages of 0.12 to 0.55 mm. The strip speed in the process section can reach a maximum of 600 m/min and, in the entry and exit sections, up to 750 m/min.

The material processed in the two electrolytic tinning lines is supplied from a continuous tinplate annealing line with a reduction and skin-pass mill and an offline reduction and skin-pass mill. The order for the supply of these facilities was already placed with SMS Siemag at the beginning of 2011.