The decade sees great technical change in the way steel is made world-wide. The basic oxygen and electric arc processes are coming to the fore while the techniques used in open hearth smelting at, for example, Hawarden Bridge Works attract attention by producing non-ageing steel with the superior surface properties of ageing steel and in large quantities.
Hawarden Bridge Works now has a high reputation for the supply of full finish deep drawing sheets to the car and domestic appliances industries and is also internationally recognised as both a pioneer and a leader in the fields of protective and decorative coatings on sheet steel. One fifth of its annual output is being coated and six coating processes are in use, namely hot dip galvanizing, electro galvanizing, paint spraying, poly vinyl chloride lamination, nickel plating and aluminium powder coating.
A fourth continuous hot dip galvanizing line, capable of zinc coating strip up to 1,220 mm wide, operating at 40 metres a minute, is installed at Hawarden Bridge Works. The maximum coil size is 15 tons. Improvements have been made to furnace design, coil handling, coating control and line outputs since the installation of the first line in 1937.
GKN ( South Wales ) Limited is producing electro galvanized steel strip up to 18 in.wide and up to 0.036 in. thick at its Castle Works, Cardiff.
Dorman Long (Steel) Limited, Middlesborough, install a line and curing oven at Ayrton Works for the trial production of pvc paint coated steel strip. The paint is supplied by Aycliffe Paints where the development was conceived.
Redpath Dorman Long Limited open a factory on the Aycliffe Industrial Estate, Newton Aycliffe, equipped with two coating lines and built-in curing ovens for the production of double-sided pvc painted steel sheets. The substrate material supplied by the company’s Ayrton Works, is shot blasted to ensure a clean etched surface for the paint, coated on one surface on one line and manually turned over for return through the second line.
The painted sheets are shaped on one of two 18 ft long press brakes, capable of providing profiled sheets up to 36 ft. long for the construction industry. Insulation material, either mineral wool or foam, are inserted between the outer profiled sheet and inner flat tray off site. Aycliffe is also supplying flashing and other components.
Coated Metals install the UK’s first continuous hot dip aluminium coating line at Pontardulais in South Wales. The line’s annual capacity is 12,000 tons.
Redpath Dorman Long install de-coiling and cut-to-length facilities at Newton Aycliffe Works to handle coils of hot dipped galvanized steel strip now sourced from the Steel Company of Wales’ Port Talbot and John Summers and Sons’ Hawarden Bridge Works.
Richard Thomas & Baldwin install a wide coil coating line at Bryngwyn Works, near Swansea. It is the first of its kind outside America and is capable of paint coating strip up to 1,330 mm wide at speeds up to 60 metres a minute.
Custom Coil Coaters opens a factory at Wolverhampton to apply non-stick coatings to steel and aluminium strip primarily for the bakeware, houseware and small electrical appliance industries.
In July, the UK’s private steelmaking companies are nationalised to form the British Steel Corporation with major strip products works at Port Talbot, Llanwern and Ebbw Vale in South Wales, Ravenscraig, Motherwell in Scotland and Hawarden Bridge Works which is renamed Shotton Works.
The European Coil Coating Association is founded to promote the use of pre-painted steel and aluminium strip products. From a base in Brussels, it currently (2020) represents over 100 companies active in coil coating
A new product Galvaprime®, mainly for agricultural building use, is produced on the No.2 continuous hot dip galvanizing line at Hawarden Bridge Works. A rotating head, installed in the exit section, sprays modified vinyl paint on to the top surface of galvanized strip. Green, grey and brown paint coatings are currently available. The same process technique is used to produce Galvaline®, light coloured sheets for the interior of doubled skinned buildings.
The world’s first line for the production of pre-treated, multi-purpose steel sheets for vitreous enamelling is installed in the Coatings One Department at Hawarden Bridge Works. The nickel coated sheets are capable of being formed and are virtually ready to accept vitreous enamel directly onto the surface, hence the product name Diron®. The sheet has a surface which has been decarburised, pre-etched (pickled) and nickel coated, suitable for all vitreous enamelling operations. The product is intended to simplify the vitreous enamelling process.
The commercial potential of the product has been deemed sufficient to warrant investment in a full-scale line. However, technical problems particularly those associated with welding will in time prevent its widespread acceptance within the enamelling industry. The development also coincides with a general decline in the use of vitreous enamelling in favour of painted steel in the consumer products markets. Poor demand will lead to the line’s conversion to electro galvanising of steel plate in 1977.
A second hot dip galvanizing line is commissioned by British Steel Corporation at Ebbw Vale Works. The £4 million line has an annual capacity of 200,000 tonnes and is designed to produce nine different coatings and finishes, some previously not manufactured in the UK. They include light differential and iron/zinc alloy coatings which are easier to weld and paint. All products are being marketed in the UK under the brand name of Zincote®, replacing Speltafast, formerly made on the No. 1 line at Ebbw Vale Works, and Dragonzin, produced at Abbey Works, Port Talbot
A new Product Development Centre opens at Shotwick on the outskirts of Shotton Works with three units, Design and Engineering, Field Development and Product Research, to assist customers and potential customers with advice and practical help on the use of sheet steel products.
British Steel Corporation closes Stalybridge Works, formerly the Globe Iron Works, where John Summers and Sons produced hot dip galvanized steel sheets for the first time in 1894.
H.H.Robertson at Ellesmere Port commission a new “hot melt” line.
On the formation of a Tinplate Group by British Steel, the Ebbw Vale Works’ product range includes galvanized, Supavit one coat enamelling steel and steel strip for Terne coating in the Midlands.
Shotton Works status as British Steel’s premier coatings location is enhanced with the commissioning of two computer-controlled coil-to-coil coating lines in the Coatings One Department.
The No. 1 Zintec® electro plating line, the first of its kind in the country, has a design capacity of 120,000 tonnes per annum operating at sixty metres a minute. It replaces the original three sheet lines which have been producing at record levels to meet the growing demand for Zintec®.
The process section of the new line has two sets of seven plating cells filled with zinc chloride electrolyte solution. As the strip passes horizontally through each section of cells it is coated on the bottom surface by the passing of current through submerged soluble zinc anodes. For double sided coating, the strip is then inverted and passed through the second set of cells.
The Stelvetite® acrylic film coating line, which replaces a pilot line, has the capacity to produce 100,000 tonnes of laminated steel strip a year. It is Europe’s first continuous laminating line and can coat strip up to 1,350 mm wide and between 0.35 mm and 1.6 mm thick operating at up to 65 metres a minute.
The line has standard continuous line entry equipment eg pay off reels, hydraulic coil car, roll flatteners, seam welder, and the cleaned and acid etched strip is electro-galvanized on both surfaces as it passes through three electrolytic tanks. Plastic laminate is bonded to strip by adhesive and a permanent bond is achieved by pressurised rolling.
By now Stelvetite® is available in a wide range of colours, patterns and woodgrains, making it one of the most versatile materials available to designers, fabricators, architects and builders. Early large volume uses were building cladding, automotive components and consumer products.
Following successful pilot line trials, a full-scale coil line for the production of Elphal® aluminium powder coated strip is installed at Shotton Works. Aluminium is applied in dry powder form to pre-treated steel strip and it is envisaged that other metals such as copper, nickel, chromium will also be applied on the line.
The line is capable of coating strip up to 1219 mm wide in gauges from 0.625 mm to 1.58 mm in coil weights up to 10 tonnes. It is designed to operate at up to 150 feet per minute and has an annual capacity of 75,000 tonnes. Standard coating thickness is 0.0015 inch, deposited on one or both sides.
The product off the line is subsequently found to be technically flawed with a tendency for the substrate-coating bond to weaken and fail over time. As a consequence, full commercialisation is not achieved and the project is abandoned.
British Steel installs a second paint coating line at Bryngwyn Works, to meet increased demand from the construction industry. Maximum strip width is 1,330 mm. and maximum line speed 80 metres a minute.
Custom Coated Coil, Birmingham commission a line for processing strip up to 700 mm wide.
Since a Product Development Centre was established in 1969 at Shotwick, on the outskirts of Shotton Works, BSC’s Strip Mills Division’s coatings capacity has increased from 650K tonnes a year to nearly 1m. tonnes. Plans are announced to extend field development facilities at Shotwick with new process equipment, pilot lines and improved facilities for design and engineering services and prototype construction. The new equipment will include an experimental multi-ply sheet laminating line, a pilot sheet coating line, an experimental surface finishing line and facilities for sheet stocking.
In March the British Steel Corporation announces plans for a new coatings complex at Shotton Works with coil-to-coil lines for hot dip galvanizing, electro zinc plating and organic paint coating.
C.Walker and Sons, Blackburn, Lancashire, acquire the Coated Metals’ aluminium coating line at Pontardulais, from W.E.Hughes and Co.
The decade sees the development of new technologies and new markets for organic painted strip. Organic coated strip steel is now marketed by British Steel under the branded product name of Colorcoat ®, a unique high- performance material initially available in 12 colours. It is the first organic coated steel product in Europe with a 200micron thick plastisol coating.
British Steel backs marketing campaigns with customer support, continuous product improvement and an expanding distribution chain.
New paint coating systems are developed by an increasing number of paint suppliers notably Berger, ICI, Pinchin Johnson, Crown Paints, Goodlass Wall, Becker, Arthur Holden, Donald MacPherson. Pre-treatment systems are developed by ICI and Pyrene, using American technology.
British Steel opens a new organic paint coating factory on the Tafarnaubach Industrial Estate, near Tredegar. It is equipped with a coil-to-coil coating line with an annual capacity of 50,000 tonnes, a unit for manufacturing building panels and a new project to produce complete ranges of kitchen furniture.
The production line will initially apply high gloss polyester to electro zinc coated substrate up to 1,400 mm wide strip for sale to the domestic appliance sector. The maximum operating speed is 60 metres a minute.
In later years, following enhancements, the line capacity is increased to 80K tonnes and is fitted with a laminator to produce Stelvetite® film laminated strip for the electronics sector
A new Coatings Two Department costing £46 million is opened at Shotton Works. It is the largest purpose-built complex of its kind in the world, housing three computer-controlled coil-to-coil lines which more than double the works’ coatings capacity to over 800,000 tonnes a year. Shotton is justifiably acclaimed “the coatings centre of Europe.” The new Coatings Two complex represents the biggest single investment at the works since full-integration developments in the early 1950s and secures a long-term future for the plant.
Operating at up to 170 metres a minute, the new No.5 Galvatite® hot dip galvanizing line coats cold reduced strip in a width range of 600-1,400mm and gauge range of 0.35-195mm with between 100 and 450 grammes of zinc or zinc alloy per square metre. Technical innovations include a vertical direct-fired non-oxidising furnace, air knife coating control, spangle minimisation equipment and in-line temper rolling and tension levelling, all necessary for improved shape and mechanical properties of the finished product.
Operating at up to 115 metres a minute, the new No.2 Zintect® electro galvanizing line processes strip 600-1,400mm wide in gauges ranging from 0.44mm to 2.0mm. Line features include a chemical and electro-degrease section, acid pickling, plating cells and a chemical post-treatment section.
The No.1 Colorcoat® line applies industrial paints to strip 600mm-1,400 wide in gauges from 0.40 to 1.6mm and operates at up to 100 metres a minute. In-line equipment includes strip pre-cleaning, chemical pre-treatment. flattening, roll coat paint application and gas-fired oven curing. The flexibility of the roll coating process accommodates a wide range of paint chemistries, colours and paint film thicknesses.
The new lines not only increase capacity and efficiency but bring improvements in strength, surface finish, corrosion resistance and colour finish.
Hot dipped galvanized steel, flat and corrugated, continue to be produced at Orb Works.