Thursday, 22 October 2015

Visiting Steelworks

Steelmaking in Bilston

My first visit to a steelmaking plant was when I was at school when I joined an educational tour around the Stewarts and Lloyds Steelworks at Spring Vale, Bilston. I think this started my interest in steelmaking and heavy engineering in general. At Spring Vale, there was one Blast Furnace, called 'Elizabeth', built in 1954. Once 'lit' blast furnaces are kept going as long as possible. A 'campaign' can last 10 - 15 years. The blast furnace produces iron from iron ore in a batch process. Every few hours, the furnace would be 'tapped' to release the new batch of 'blast furnace metal'. Originally, this would be sand-cast into 'pigs', allowed to solidify, then broken up and carried away for further processing which involved melting it again. In an 'Integrated Steel Works', blast furnace metal is kept molten and transferred immediately for further processing. The Spring Vale Works had a number of electric-arc furnaces, used for converting iron into steel.

The Blast Furnace at Bilston (Photo: Wolverhampton City Council).

I wasn't able to visit the Bilston steelworks again but, after I started visiting railway signal boxes (there's a brief introduction here), I was able to watch the traffic flows in and out of Bilston steelworks - iron ore, coke, coal and other minerals in; steel in different forms out. Various posts with the label 'Railway Signalling' mention this traffic and the post Spring Vale Sidings Box details the main line signal box adjacent to the steelworks.

Re-nationalisation of the steel industry

In 1967 the steelmaking industry in Britain was nationalised (for the second time) as the British Steel Corporation. Rationalisation and heavy investment followed to modernise the industry. The more efficient Basic Oxygen Steel process was introduced at certain sites, together with new, larger blast furnaces which, whilst still batch-orientated, had a much larger throughput than 'Elizabeth' at Bilston steelworks. So the Bilston steelworks became less economical, leading to closure in 1979. The works was demolished and there is little trace now of the Bilston works. There's a brief history of Bilston Steelworks in the article:-
The History of Wolverhampton: The City and & its people: Bilston Steel Works.
There's a more detailed account in the article:-
Bilston Steel Works.

My introduction to steelmaking on Teesside

I spent a few years working at Contactor Switchgear (Electronics) Limited in Wolverhampton and, although much of the equipment was destined for various steelworks, I don't think I managed a site visit.

It was only after I set up on my own as an electronics consultant that I was invited to visit a steelworks in the north-east to help out with a problem, as described in the post Flying. That post concluded with the remark "I'm glad to report that our hastily-constructed control module performed better than I'd dared hope and we subsequently did quite a bit of work for various steelworks supplying materials handling equipment of our design".

I'd been asked to make that first trip by Babcock-Moxey in Gloucester. I was already familiar with Babcock & Wilcox from my work on equipment for West Thurrock Power Station (described in the post The World of Work) but I didn't know much about Babcock-Moxey. Later, I found out that 'Moxey' had been set up in 1935 in Birmingham to produce conveyor systems. By 1963 they had been taken over by Winget Ltd and moved to Gloucester then, in 1968, Babcock & Wilcox acquired the Winget activities in Gloucester where they were producing Bucket Wheel Stacker Reclaimer machines and the associated conveyor systems.

Redcar: Bucket Wheel Stacker Reclaimer (Photo: Babcock Moxey).

Electronic Vibratory Feeders

The work we'd become involved in was the manufacture of Electronic Vibratory Feeders for bulk materials handling. Conventional Vibratory Feeders had been in use for many years where a shaker table is deliberately vibrated by a motor which imparts a circular or elliptical motion to the table so as to move the material being handled. This can be particularly helpful in discharging material from a hopper, for instance. Babcock Moxey were operating at the high-capacity end of the market, where material flow rates of up to 6,000 tonnes per hour were required. At these high throughputs, wear and maintenance costs with conventional vibratory feeders can be unacceptable so a Babcock Moxey subsidiary company had produced a design for an electronic vibrator controller for these applications.

The design used 440 volts single phase 50 Hertz a.c. which was half-wave rectified by a high power thyristor. By providing phase angle control of the thyristor, control of the power of the output pulses was achieved. These pulses were applied to a large electromagnet designed by our client for each application. The electromagnet was coupled to the shaker table and, in between pulses, mechanical springing restored the shaker table to its original position. Although we could control the thyristor quite readily and repeatably, achieving the rated output relied crucially on getting the spring rates correct and that could prove quite difficult.

One of our Electronic Vibratory Feeders, rather dusty after many years in service.

Babcock Moxey and the modernisation of the steel industry

Babcock Moxey had wide experience in controlling material flow in heavy industrial plant and undertook a number of major projects for British Steel Corporation, in addition to projects for the National Coal Board, the Central Electricity Generating Board and various overseas customers. The projects for British Steel Corporation were:-
Lackenby (1970)
Scunthorpe (1972)
Cleveland (1972)
Clay Lane (1972)
Consett (1973)
Redcar (1973)
Port Talbot (1974)
Llanwern (1974)
Hartlepool (1974)
Redcar (1975)
Hunterston (1977)
Port Talbot (1978)
Port Talbot (1982)
During this period, my firm supplied a number of variations of electronic controller for Vibratory Feeders and I was able to visit most of the sites in the North East to assist during commissioning. When I can, I'll add more about my visits to British steelworks.

In 1988, the Gloucester offices were closed and Claudius Peters Group GmbH (part of Langley Holdings plc) acquired the business. There's a brief history of Babcock Moxey at Gloucester here.

Basic Oxygen Steelmaking

Modern steelmaking largely relies on the Basic Oxygen Steel process for the economic production of steel, rather than the earlier Bessemer process, Open hearth furnace or the Electric arc furnace methods. There's a description of the Basic Oxygen Steel process here. Tata Steel have a very easy-to-follow video here. This is one of an excellent series of Teaching Resources provided by Tata Steel, listed here.

Re-privatisation of the steel industry

Also in 1988, the steel industry was privatised again under the trading name 'British Steel'. Despite the modernisation, difficult times lay ahead and, in 1999, British Steel merged with the Dutch steelmaker Koninklijke Hoogovens to form Corus. Further rationalisation ensued and Corus was taken over by the Indian company Tata Steel in 2007. The economic prospects for the British steel industry continued to deteriorate during the general recession and Tata Steel closed the massive Redcar blast furnace in 2009. Two years later, the Thai-owned Sahaviriya Steel Industries (SSI) purchased the Redcar plant which re-opened in 2012 but the group collapsed into liquidation in October 2015 with the loss of around 2,000 jobs. 2015 is proving an 'annus horribilis' for the steel industry. Tata Steel have announced plans to cut 900 jobs at its Scunthorpe site and a further 270 at Dalzell plate rolling works in Motherwell and the Clydebridge plant in Cambuslang. In addition, Caparo Industries have been placed in administration, threatening up to 1,700 jobs, just days before I wrote this.