Steel before the 18th century
Steel is one of the world’s most essential materials. It is fundamental to every aspect of our lives, from infrastructure and transport to the humble tin-plated steel can that preserves food. With steel, we can create huge buildings or tiny parts for precision instruments. It is strong, versatile and infinitely recyclable.The rise of steel began with the 19th century Industrial Revolution in Europe and North America. Yet steelmaking isn’t new. Master craftsmen in ancient China and India were skilled in its production. However, it is only in the past 200 years that science has revealed the secrets of this remarkable material. Today, steelmakers know how to combine the exact mix of iron, a small percentage of carbon and other trace elements to produce hundreds of types of steel. These are then rolled, annealed and coated to deliver tailor-made properties for innumerable applications. This book traces major milestones in the history of steel, highlighting some of the many inventors, entrepreneurs and companies that have shaped its development. Steel has an exciting past and an even more exciting future. Steelmakers continue to reduce the energy required to make steel. Modern high-strength steels provide more strength with less weight, helping reduce the emissions of carbon dioxide of end products such as cars. And because steel can be so easily recycled, supplies will remain abundant for generations to come.
A happy discovery
However, iron is not steel. Iron Age metal workers almost certainly discovered steel as an accidental by-product of their ironworking activities. These early smiths heated iron ore in charcoal fires, which produced a relatively pure spongy mass of iron called a ‘bloom’ that could then be hammered (wrought) into shape.These early smiths would have noticed that when iron was left in the charcoal furnaces for a longer period, it changed. It became harder and stronger: qualities they undoubtedly recognised as valuable. They would also have noticed that these qualities improved with repeated heating, folding and beating of the material as they forged the metal.
One of the earliest references to steel-working comes from Greek historian, Herodotus, referring to a bowl inlaid by Glaucus of Chios in the seventh century BCE: “A great bowl of pure silver, with a salver in steel curiously inlaid. Glaucus, the Chian, made it, the man who first invented the art of inlaying steel.”
A global industry begins
Iron Age steelmakers did not understand the chemistry of steel. Its creation held many mysteries and the final result depended on the skill of individual metal workers. First among these were the craftsmen of southern India. As early as the third century BCE, they were using crucibles to smelt wrought iron with charcoal to produce ‘wootz’ steel – a material that is still admired today for its quality.
Chinese craftsmen were also manufacturing high-quality steel. It seems that the Chinese had something similar to the Bessemer process as early as the second century BCE, which was only developed in Europe in the 19th century. Steel agricultural implements were widely used in the Tang Dynasty, around 600-900 CE.Moreover, with expertise came trade. The skills of traders in India and China created an international market in steel. Many historians believe that the famous Roman natural scientist and writer Pliny the Elder was referring to China when he described ‘Seres’ as the best source of steel in the world. And Damascus swords, celebrated for their exceptional quality, were made of wootz steel from India.
Damascene mysteriesA legend in their own time, Damascus swords were renowned for their sharpness and wavy surface patterning. They were made from wootz steel, which probably originated in Central Asia or Southern India. To this day, nobody has been able to reproduce the characteristics of this remarkable steel.
The rise of crucible steel
This interest reflected the continued growth in iron and steelmaking across Europe. As early as the 12th century, technologies such as blast furnaces, already known in Asia, began to emerge. The remains of one of the earliest examples can still be seen at Lapphyttan, in Sweden. Indeed, thanks to its rich iron-ore deposits, advanced production techniques, and the purity of its wrought iron, Sweden became a major supplier of high-quality iron to steelmakers across the continent.
Production speed heats up
Mostly, the steelmakers of the time were producing steel using the cementation process, in which wrought iron bars are layered in powdered charcoal and heated for long periods to increase the carbon content in the alloy. It was a process that could take days or weeks.
Then in 1740, a secretive yet highly inventive young Englishman called Benjamin Huntsman revealed his new crucible technique to master cutlers in the north of England. Using a clay pot, called a crucible, he was able to achieve temperatures high enough to melt the bars created in the cementation process and ‘cast’ (pour) the resulting liquid steel to create steel ingots of uniform high quality and in relatively high quantities – at least in comparison with what had gone before. Huntsman’s invention was not the final step towards low-cost, high-volume production of high-quality steel. It would take other inventors to achieve that goal. He had, however, provided the impetus for one of the greatest steelmaking centres of the 19th and 20th centuries – Sheffield, England.
Clock springs to cutlery
Huntsman’s invention began with clock springs. As a clockmaker, Huntsman was dissatisfied with the quality of existing steel parts from Germany, so he set out to make his own steel. Remarkably, when he first approached the cutlers of Sheffield with his crucible steel, they refused to work with it. Only when they were unsuccessful in trying to block him from exporting it to French manufacturers did they finally start using it.
18th to 19th century
Huntsman’s development of the crucible process was just one invention of the Industrial Revolution, a time of huge technological creativity. Originating in Britain, the Industrial Revolution led to massive changes in manufacturing, trade and society worldwide. When it began in the 18th century, iron still dominated the industrial landscape. By its end in the early 20th century, steel was king, the metal at the heart of the modern world.
From trees to steam
The Industrial Revolution and modern steel manufacture began with a shortage of trees. Up to the 1700s, British iron and steelmakers used charcoal both in their furnaces and to ‘carburise’ iron. But with agricultural and industrial expansion, wood became in increasingly short supply. So metalworkers turned to coke, made from coal, as the fuel for reverberatory furnaces, where heat radiated off the walls and roof to create temperatures high enough to melt the ore.
Then in 1709, Abraham Darby perfected the use of coke in a blast furnace to produce pig iron for pots and kettles. This new technique helped boost production, leading to further demand for coal and coke. But coal mining had a problem: how to keep underground mines from flooding.Thomas Newcomen developed a revolutionary solution, the ‘atmospheric engine’, a forerunner of the steam engine, in 1712, and it changed the world. By 1775, James Watt had created an improved steam engine; by 1804, the first railways had been built. Where industries such as textiles once relied on manual labour, watermills and horses, steam brought mechanisation and mass production.
Building with metal
The foundations of the modern world
Steel makes its mark
Above all, steel played a key role in opening up the prairies of the Midwest. Wrought iron ploughs simply broke in the heavy soils, so a quick-thinking young blacksmith called John Deere created a plough with a steel blade. In the next 50 years, the steel plough and steam-driven equipment transformed agriculture, not just in the US but in Europe as well. Mechanisation had arrived on the land.
Pipes and welds
Very soon, however, they optimized the rolling process by using a plug to ensure more uniform piercing and a smoother inside surface. The need for pipes to be perfectly sealed has helped drive welding techniques, as well as the development of steels that can withstand high welding temperatures without cracking or weakening.
Famous names in steel
Some of today’s leading steel companies have their roots in the 1800s. For example, Friedrich Krupp and partners formed the Krupp Company in Germany in 1811. By the end of the century, it was the largest steel company in Europe and today is part of thyssenKrupp. In Japan, Nippon Steel (today Nippon Steel Corporation) can trace its history back to 1857, when steel was successfully tapped from Japan’s first Western-style furnace at Kamaishi.
Into mass production
Although not quite as fast as the Bessemer process, open-hearth techniques allowed for more precise temperature control, resulting in better-quality steel.
The Bessemer converter
Bessemer aimed to create steel by driving the impurities out of pig iron. Air-pumps forced high-pressure air through molten iron in his egg-shaped furnace. Rather than cooling the iron, the air reacted with impurities such as carbon, manganese and silicon in the iron, causing them to oxidise. This raised the temperature further, igniting even more impurities and producing a violent display with sparks and flames erupting from the converter’s open top like a volcano. Fast and cheap, when finally perfected this spectacular process took less than half an hour to turn pig iron into steel.
Ancient technique, modern success
Bessemer was not the first to invent an air-injection process to create steel. Such techniques had been used in ancient China. William Kelly, an American inventor, independently came up with such a process in the 1850s, possibly inspired by Chinese know-how. Kelly subsequently went bankrupt, and even Bessemer struggled to make his process work. It was advice from Englishman Robert Mushet, an expert metal-worker, to blow off all the impurities then add carbon back into the metal that finally led to a high-quality, malleable (rollable) product.
Material of choice
Building the future
Andrew Carnegie’s life is the classic ‘rags-to-riches’ tale. Born in Dunfermline, Scotland, his family emigrated to the US in 1848. Carnegie started work aged 13, earning just 20 cents per day. At 18, he was employed by the Pennsylvania Railroad Company, where he advanced rapidly up the organization while learning much about business. In 1870, he founded the Carnegie Steel Company, which grew to become the largest and most profitable industrial enterprise in the world by the 1890s.
At age 66, Carnegie sold the company to financier, banker and philanthropist J.P. Morgan, who developed many improvements in mill design and rolling of steel that were built on and improved over the decades to come – Carnegie, meanwhile, devoted the rest of his life to investing his wealth in projects for the public good. These ranged from libraries to schools and hospitals and included the Carnegie Institute of Technology, now part of the Carnegie Mellon University.
20th century global expansion, 1900-1970s
The steel age
By the dawn of the 20th century, steelmaking was a major industry and science was increasingly unlocking the mysteries of steel. A British ‘gentleman scientist’ named Henry Clifton Sorby created a sensation by putting metal samples under a microscope. His pioneering work revealed steel’s secret – it gained its strength from the small, precise quantities of carbon locked within the iron crystals.
With greater understanding of the properties of steel, steel alloys became more widespread. In 1908, the Germania, a 366-tonne yacht built by the Friedrich Krupp Germania shipyard had a hull made of chrome-nickel steel. And in 1912, two of Krupp’s German engineers, Benno Strauss and Eduard Maurer, patented stainless steel, the invention of which is in fact usually credited to Harry Brearley (1871-1948), a Sheffield-born English chemist who, during his work for one of the city’s laboratories, began to research new steels that could better resist the erosion caused by high temperatures, and examine the addition of chromium, which eventually resulted in the creation of what is probably the best-known alloy of all.
The impact of war
Welcome to the white-goods era
From these beginnings in the 1960s, the range of HSLA steels has grown enormously. They are used in everything from bridges to lawnmowers. Above all, they offer a much greater strength-to-weight ratio than traditional carbon steel. Typically, they are around 20-30% lighter than carbon steels, with the same strength. This property has made them especially popular with carmakers, allowing cars to be strong and safe, yet also light and fuel efficient.
Strengthening international bondsWhile steel was providing the foundations of modern society, the steel industry was acting as a focus for new relationships between countries. In 1951, France, West Germany, Italy and the Benelux nations joined together in the European Coal and Steel Community (ECSC).
The community created a ‘common market’ to drive economic expansion, promote industry and raise living standards. With its focus on free movement of products, the European Coal and Steel Community was the first step on a journey that ultimately led to the creation of the European Union.
From flame to electricity
In the mid-20th century, steelmaking advanced on many fronts. Basic oxygen steelmaking and electric arc furnaces transformed the main production processes, making them faster and more energy efficient. They even allowed manufacturers to reuse scrap as input material.Along with introducing new primary techniques, steelmakers also improved on traditional techniques of casting and rolling to create sheets, shapes, and steel to precise customer requirements. Some of these developments came from Europe, the USA, and Russia. But new steelmakers, especially in Japan and Korea, quickly developed their own innovations that in turn inspired steelmakers worldwide. What exactly were these new techniques? The first – basic oxygen steelmaking – is essentially a refined version of the Bessemer converter, which uses oxygen rather than air to drive off excess carbon from pig iron to produce steel. The process was invented by a Swiss scientist named Robert Durrer in 1948, and was then further developed by Austrian company VÖEST AG (today voestalpine AG). It is also known as the Linz-Donawitz (LD) process, after the Austrian towns in which it was first commercialized. Most importantly, the process is fast. Modern basic oxygen furnaces (BOFs) can convert an iron charge of up to 350 tonnes into steel in less than 40 minutes – compare this with the 10–12 hours needed to complete a ‘heat’ in an open-hearth furnace.
Making the most of scrap
In addition to these new ways to produce raw steel, new ways to cast (pour) the molten metal into molds emerged. Up to the 1950s, steel was poured into stationary molds forming ingots (large blocks) that were then rolled into sheets, or smaller shapes and sizes. In continuous casting, liquid steel is fed continuously into a mold in a conveyor belt-type process, creating a long strand of steel. As the strand emerges from the mold, it is cut into slabs or blooms, which are much thinner than traditional ingots and thus easier to roll into finished and semi-finished products.
Steels for every purpose
The continuous casting process
Finished to perfection
The complex task of rolling ingots or slabs begins with ‘roughing.’ Giant rollers make a number of passes to reduce the thickness of the material – for example, taking a slab down from around 240mm to 55mm or less. Next come numerous finishing rolling steps before recoiling. Then the material can take a number of routes, one being pickling to remove the scale, followed by cold rolling.
Finally, the steel may be coated to protect it from rust and corrosion – this is especially important in applications such as shipbuilding, bridges, and railways where the metal can be exposed to heat, cold, salty seawater, and rain. Hot dip galvanizing is widely used to coat steel with a layer of protective pure zinc or a zinc-aluminum mix. For other applications, the surface may be pre-primed to take paint, or treated for UV and scratch resistance, or given a dedicated treatment or coating from a vast palette of colors that add functional or decorative finishes.
The mini mills transformation
The rise of EAF in the 1960s paved the way for mini mills and a significant change in the steel industry. Traditional integrated mills based on BOFs require a blast furnace to supply molten iron as input. They are large and costly to build. Mills based on an EAF are different. Using scrap or direct reduced iron (DRI) or pig iron as input materials, they are generally smaller and simpler to build and operate – hence the name ‘mini mills’. They can also be set up with a smaller level of capital, and that opened the door to a new breed of entrepreneurs.
Steel is used in hugely demanding applications from shipbuilding to pressure vessels in nuclear power stations. It is also trusted by millions of people to keep a roof over their head. Galvanised corrugated roofing is a familiar sight worldwide. Galvanization has been known since the 19th century, but in the 1930s, a young Pole, Tadeus Sendzimir, invented a way to galvanize steel in a continuous production process. His Sendzimir Company also became a world leader in cold rolling, and the steel skin for the Apollo spacecraft was produced in one of its mills.
Recycling ahead of its timeMini mills are effectively recycling plants. They take in scrap metal and convert it into useful steel. Today, the importance of this is clear, not just commercially but for the benefit of the planet, as it saves the use of natural resources/raw materials. In the 1960s, however, the concept of ‘sustainability’ was only just starting to emerge.
The question of how far the planet could sustain growing populations hit the headlines in 1970, when a group of politicians, academics, and industrialists published The Limits to Growth. Among the group was Dutchman Max Kohnstamm, a former secretary of the High Authority of the European Coal and Steel Community. Although the report’s findings caused controversy at the time, governments and industry bodies worldwide now agree that manufacturing’s future depends on efficient, sustainable use of energy and resources. It was complemented by the Brundtland Commission report Our Common Future, in 1987, which addressed similar themes.
End of 20th century, start of 21st
Going for growth: Innovation of scale
While mini mills were emerging in the USA and Europe, Asia saw innovation in scale and output. Pursuing rapid growth in the 1960s and 1970s, Japan, followed closely by South Korea, developed massive state-of-the-art integrated facilities. These generated high-quality flat products from coils to coated and galvanized sheets, targeted at sectors such as automotive and appliance manufacturing.Unlike older steelmaking countries, neither Korea nor to a lesser extent Japan had a legacy of open-hearth furnace production. Instead, partly due to a lack of domestic scrap, they advanced directly to innovative basic oxygen furnace (BOF) technology, building giant blast furnaces to supply the pig iron input.
Continuing innovationOld or new, Japan and Korea’s companies are committed to innovation. Created in 1970 from the merger of Yawata Steel and Fuji Steel, Nippon Steel Corporation can trace its roots back to 1857. Now Japan’s biggest steelmaker, it invests extensively in continued process improvement and in ensuring steelmaking plays its role in respecting the planet.
In South Korea, POSCO began life only in 1968 during the country’s rapid economic expansion. By 1985, its first plant in Pohang was producing 9.1 million tonnes of crude steel per year and work had begun on a second in Gwangyang – now one of the world’s largest steel mills.
Enter the entrepreneurs
Mini mills expand into new markets
Initially mini mills produced low-value rebar steel (concrete reinforcing bars). With small melting chambers and input of scrap, they could not compete with high-quality products from integrated mills.
However, as the rebar market became saturated, mini mill owners developed ways to produce higher value structural steel. In 1987, Nucor pioneered the use of an EAF and compact strip production (CSP) from German company SMS SchloemannSiemag to produce sheet steel. By starting with thin slabs of just 40-70mm, CSP dramatically reduced the time and number of rolling stages needed to produce steel as thin as 1mm. And for mini mills, it meant a cost-effective way to enter the sheet-steel market.
Privatisation brings added growth
Despite years of lack of investment, at the time of its dissolution in 1991, the Soviet Union had overtaken Japan to become the world’s biggest steel producer. In the 1990s and 2000s, privatisation brought massive investment in new equipment to speed production and reduce costs. At the same time, the rapidly growing Russian economy of the 2000s coupled with neighboring China’s economic boom created huge demand, providing the Russian industry with a vast export market and ensuring its place as a top-five global steel producer.
Innovation and global connections
Tata: Building on India’s steel traditions
India’s steel industry owes much to Jamsetji Nusserwanji Tata. In the late 1800s, Tata believed steel could kick-start India’s own industrial revolution. While he did not live to see his dream realized, his prospectors found an ideal location for India’s first commercial steel plant at Sakchi, north-east India, which began operations in 1912. Tata also wanted to create a great city for his workers to enjoy life. Built by his sons, that city – called Jamshedpur in Tata’s honor – is now home to more than 1.3 million people, and is among India’s richest and cleanest cities. In 2007, Tata Steel acquired Anglo-Dutch manufacturer Corus.
Latam’s European connections
Brazilian company Gerdau is the largest producer of long steel in the Americas and one of the largest suppliers of special steel in the world. With production facilities in the Americas, Europe, and Asia, it was established by German immigrant João Gerdau and his son Hugo in 1901. A true family business, Gerdau has been built on respect for employees and customers. It is also the leading recycler in Latin America, reflecting the importance of environmental responsibility in its ethos.The Techint group, another giant of Latin American steelmaking, was set up in 1945 by Italian engineer, Agostino Rocca. It was heavily involved in the development of Argentina’s industrial infrastructure, including the construction of a 1,600km gas pipeline from Comodoro Rivadavia to Buenos Aires in 1949. Today, Tenaris – one of the group’s companies – is a world leader in the manufacture of seamless steel tubes, mainly for the oil and gas industry. Another group company, Ternium, is a major player in flat and long products in Latin America.
The steel dragon
Steel for the GamesShougang (Capital Steel) is one of China’s oldest state-owned companies. Its Beijing plant, founded in 1919, was originally built on the outskirts of the city but has since been swallowed up by urban growth. In 2005 as part of a huge drive to rejuvenate the city ahead of the 2008 Olympic Games, the entire plant was relocated 150 km away to a purpose-built island off the coast. The Beijing National Stadium – the so-called Bird’s Nest stadium – built for the games used 42,000 tonnes of steel, making it the world’s largest steel structure.
An industry on the move
The steel industry has seen its focus shift towards the emerging economies, as these require a huge amount of steel for urbanization and industrialization. In 1967, when the World Steel Association first came into being as the International Iron and Steel Institute, the US, western European countries, and Japan accounted for 61.9% of world steel production. By 2000, this had been reduced to 43.8%. This trend accelerated in the 2000s, with the rise of China and from 2011 onwards with emerging countries accounting for more than 70% of steel use and production – China now represents around 45%. This shift in momentum looks likely to continue with other developing economies, such as India and countries in the Association of Southeast Asian Nations (ASEAN) and Middle East and North Africa (MENA).
Steel industry today and future developments
Steel is everywhere in our daily lives from buildings and vehicles to the tin can that conserves food safely for months or years. It is the world’s most important engineering material. Nonetheless producing steel is extremely energy intensive. However, once produced, steel can be used again and again. With a global recovery rate of more than 70%, steel is the most recycled material on the planet. What’s more, 97% of by-products from steel manufacturing can also be reused. For example, slag from steel plants is often used to make concrete.Thanks to continuous improvement of steelmaking processes, it now takes 50% less energy to make a tonne of steel than it did thirty years ago. Using less energy means releasing fewer greenhouse gases, a key factor in combating climate change. Indeed, considered over its entire lifecycle, steel products can have less environmental impact than products made from alternative materials such as aluminum or plastic. Moreover, today’s advanced high-strength steels are stronger and lighter, so less steel is required to deliver the same structural integrity. A lighter car or cargo ship will be more fuel efficient, reducing their greenhouse gas emissions. Steel also has an important role in the world’s growing infrastructure for renewable energy. The latest steels are enabling taller, stronger, lighter-weight towers for wind turbines, increasing their efficiency and reducing the carbon emissions associated with their construction by up to 50%. New roofing systems combine photovoltaic cells with galvanized steel panels. Steel producers are even working with the solar industry to explore innovations such as roofing coated with dyes that can directly generate electricity. At the same time, steel plants are cleaner and safer than ever before. Improving health and safety is a key industry goal, with manufacturers continually striving to reduce accidents at work. As a result, the industry’s lost-time injury frequency rate halved between 2004 and 2009 – the industry is now aiming for an injury-free workplace.
Co-operation on ‘greener’ carsA modern car consists of around 50-60% steel. Over the years, steelmakers and the automotive industry have worked closely to make cars stronger, safer, and rust-resistant. Advanced high-strength steels can reduce lifetime greenhouse gas emissions of a typical five-passenger vehicle by 2.2 tonnes. And the industry is working to go further. In the 1990s already, the Ultra Light Steel Auto Body (ULSAB) program showed ways to achieve weight reduction with a body that fulfills or exceeds performance and crash resistance at potentially lower cost. A similar program for electric vehicles, FutureSteelVehicle (FSV), whose results were released in 2011, revealed potential reductions to total life cycle emissions by nearly 70% compared to a current benchmark vehicle. This was achieved through 97% use of High-Strength (HSS) and Advanced High-Strength Steels (AHSS).
A steel future?
Steelmakers worldwide continue to improve processes and create new steels for new purposes. Many have their own R&D organizations, but partnership is also a hallmark of steel innovation. For instance, POSCO and Siemens VAI jointly developed the FINEX process, a lower cost, more environmentally friendly alternative to traditional blast furnaces for producing hot metal. The industry-wide FutureSteelVehicle initiative aims to bring more than 20 new grades of lighter weight, cheaper advanced high-strength steels to the market by 2020. There is widespread participation in programs to reduce CO2 emissions such as ULCOS in Europe, Course 50 in Japan, and the AISI CO2 Breakthrough Program in North America. And the industry is increasingly adopting a life cycle approach to increase efficiency, reuse, and recycling at every point of a product’s life cycle from raw material extraction to recycling of end-products.