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Technological Innovation in Steel Industry

In the paper "Summary: Technological Innovation" authored by F. Bonmo, in the book "The Steel Industry in the New Millennium", the author summarized general development of the steel industry in recent years and the future trends. Some points of the paper are abstracted in this article.

Strong competition is taking place between the traditional concept of steelmaking based mainly on integrated works and the present trend towards mini mill production. This competition has significantly accelerated manpower reductions in the iron and steel industry that were already taking place due to technical improvements. For example, the labor required to make cold rolled sheet has gone down from about 10 man hours per ton at the end of the 1970s to the current 3-4 man hours per ton at an integrated works, and less than one man hour per ton at the most recent mini mills.

Mini-Mill and Related Technologies

Competition from mini mills is very active due to the following issues:

  • Lower specific investments and much lower total investment needed, allowing newcomers to enter the business. This has helped bring about the collapse of the past structure of the industry;
  • The mini mills advantage of lower man hours per tonne of product;
  • The opportunity to locate production units near steel users;
  • Greater flexibility of the mini mill route;
  • Lower environmental impact.

A further incentive to the spread of mini mills is the recent development of important new technologies more suitable for application in mini mills as compared with conventional integrated plants. In particular, the following technologies have to be mentioned:

  • melting reduction using the Corex process from VAI. By avoiding the use of coke, Corex makes it possible to save the investment costs of coke ovens.
  • Thin slab technology for hot strip production. Examples discussed here include CSP from SMS and ISP by MDH/Arvedi. By using direct rolling and lower thickness slabs, reheating furnaces can be saved. A temperature homogenization furnace can be used in place of a reheat furnace. The length of the rolling train is reduced as less reduction is required from a thin slab.
  • Continuous linking of downstream pickling and cold rolling allow the production cycle to be further compacted.

Important technological steps are expected in the near future. For example, second generation smelting reduction should allow, not only the substitution of coke with coal, but also the use of fine ore in place of lump ore. In this way it will be possible to eliminate sinter plants used to agglomerate fine ores in existing integrated works. Successful development of strip casting can be anticipated. Casting steel strip directly will get rid of the rolling process. This would allow a great saving on the transformation cost. Above all it would save on the huge capital investment in hot strip mills.

EAF Steelmaking

The electric arc furnace is at the heart of the competition between megamills and mini mills. The EAF is more suitable than other liquid steel sources for the simple, flexible and compact' concept, at least in the short to medium term. EAF steelmaking might reach a share nearer to 50 per cent by the year 2010.

The growing importance of the electric arc furnace has given rise to rapid technological progress. In the past decade there have been remarkable savings in energy, refractory use and electrode consumption coupled with significant improvements in productivity. Recent major innovations in electric steelmaking have aimed to reduce environmental impact, to further improve energy savings and productivity, and to diversify the charge material. The following technologies deserve mention:

  • Twin shell furnaces;
  • continuous charging and preheating of scrap;
  • Oxygen and carbon injection and post-combustion technologies, allowing substitution of electrical energy with less expensive chemical energy.

Scrap Issues

It is recognized that increased electric arc furnace utilization is linked to availability of ferrous charge material, at the moment mainly scrap. This focuses attention on the scrap problem: either there is enough scrap to meet the likely higher demand, or its price will increase to the point where electric arc steel will become far less competitive relative to integrated steel production. If scrap prices increase, electric arc steel output will not reach the high level forecast for the year 2010. Scrap substitutes play an important role in the overall picture. These include directly reduced iron (DRI) and ordinary iron (either hot metal or cold pig iron). Development of new directly reduced ironmaking technologies, like FINMET and others, may significantly decrease the cost of DRI to the point where it could become competitive with the scrap price, even in places where energy costs are currently too high for economic production. In this event, the forecast for future electric arc production could well be realized. Substitutes for scrap will play an important role as a supplementary charge material in any event. Some high purity charge material is required to dilute residuals in scrap. The spread of mini mills for flat products increases the importance of scrap substitutes as a pure charge material. Even if scrap supplies are readily available, some alternative charge material will be required for quality reasons.

This general scenario does not apply with equal force in different geographical regions. Perhaps scrap will not be a problem in the older industrialized areas such as the USA, the European Union and Japan. Whereas a shortage can be envisaged in the emerging industrialized economies, especially in Asia. For example, South Korea, China, Taiwan and India are likely to experience scrap deficits. Scrap substitutes are likely to be widely used in these countries. Current examples include production of hot iron from COREX in South Korea, pig iron from small blast furnaces in China and coal based DRI in India.

Upgrade/Replacement Issues

The impact of the emerging alternative iron-modern electric arc steelmaking technologies on existing plants is hard to assess. These new technologies compete with the traditional blast furnace-basic oxygen steelmaking route and with scrap based electric arc based plants using conventional continuous casting and rolling technologies. No doubt the most modern or recently upgraded works will continue producing in the usual way for many years. It is not economic to replace still efficient plants with new plants since the extra capital costs cannot be compensated by the flow of lower operating costs. A few years ago it was thought that coke shortages arising from coke ovens reaching the end of their lives would result in closure of integrated works. Reconstruction of coke ovens is expensive. Instead, pulverized coal injection (PCI) is now routinely used to replace coke in the blast furnace. The technique is likely to be further used and expanded in the near future. In the longer term blast furnaces might be replaced by smelting reduction plants. The possibility of installing more environmentally friendly and technologically advanced coke ovens cannot be excluded.

Remarkable plant engineering activity can be anticipated over the next few years. Some forecasts indicate that world steel demand might reach 1000 million tons a year by the year 2010. Rising demand coupled with a high propensity towards innovation are expected to trigger a high level of plant construction. Looking forward, estimates suggest by the year 2010, new plant of about 250-300 million tons annual capacity, and upgrading of existing plants with a capacity of around 170 million tons a year will be required.



[1] R. Ranieri and J. Aylen (ed.): The Steel Industry in the New Millennium. Vol. 1: Technology and Market. 1998. IOM Communications Ltd. ISBN 1-86125-019-3.


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