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Steel Finishing
Special coatings of zinc, polyvinyl chloride or acrylic film are applied to strip steel in the Coatings No1 Department at the British Steel Corporation's Shotton Works, Deeside, Clwyd.
H D Galvanising
Hot dipped galvanising has been practised at the works since the turn of the century when bars of steel imported from America were manhandled into pots of zinc. Today, coils of mild strip steel are processed on continous lines operating at up to 30metres minute.
The strip is cleaned, annealed and cooled before it is passed through a bath of molten zinc for a coating applied to both sides of between 240 and 700 grm per square metre.
On one of the four lines, the process is taken a stage further with the application of a coating of prime paint in green, red or slate grey.
A large proportion of the output from the section is sold in coil form, the balance being cut into sheets, flat or corrugated.
The product has a high degree of corrosion resistance and ductility, and is used, for example, in the cladding and roofing of industrial and agricultural buildings.
Electro-zinc Plating
Between 3,000-4,000tonnes of strip a week are at present electro-zinc plated on a coil line commissioned in 1972, and a plate line, commissioned in 1977. They are the only lines of their kind in the country.
The Zintec coil line, which has considerably exceeded its design capacity of 120,000tpa, coats strip up to 1.37 metres wide in gauges ranging from 0.45 mm to 1.6mm. The zinc coating is 0.0025 to 0.0075mm thick.
At the entry end of the line, the strip passes through a three roll leveller and trimming shears into a single pass spot welder. After welding, the strip goes into an accumulator, an alkaline cleaning section, a water spray tower and finally before plating, through cold dilute hydrochloric acid pickle and rinse sections.
Seven plating cells coat the bottom side of the strip and seven, the top. The anode of the cell consists of zinc blocks stacked on carbon conductor bars in the bottom of each cell and the strip passes over stainless steel conductor rolls...
