by Vaclav Smil
Submultiples Used in the SI
Prefix Abbreviation Scientific Notation
deci d 10−1
centi c 10−2
milli m 10−3
micro μ 10−6
nano n 10−9
pico p 10−12
femto f 10−15
atto a 10−18
zepto z 10−21
yocto y 10−24
Appendix B
Some Basic Terms
Austenite is a dense face-centered cubic structure of iron that forms when ferrite is cooled to 1400°C.
Basic oxygen furnace is used to convert pig iron to steel: it is a massive pear-shaped vessel lined with refractory material and mounted on trunions so it can be tilted for charging with pig iron and steel scrap and for discharging of liquid steel. Water-cooled oxygen lances are inserted through a removable lid.
Bessemer converter is a massive egg-shaped vessel that provided the first practical means of producing inexpensive steel from pig iron through decarburization. The converter was lined with a refractory material, and after it received hot metal through its open top, the charge was blasted for 15–30 min with cold air led through tuyères. The resulting exothermic oxidation removed carbon and silicon from the hot metal.
Billets are round or square-profile (up to 25 cm) pieces of steel produced by continuous casting that are converted to bars and rods.
Blast Large volume of air (>5000 m3/min) is generated by a turbo blower (cold blast) and then led to hot stoves, where its temperature is raised to as much as 1300°C before it is forced through tuyères into a blast furnace to supply oxygen for carbon oxidation and heat for iron ore smelting.
Blast furnace is a tall, conical structure set on massive foundations. Its parts, proceeding upwards, are: circular hearth with water-cooled tuyères situated along its perimeter; bosh, a short, truncated, and slightly outward-sloping cone; belly, the widest section; stack (shaft), the longest and slightly narrowing section where descending ore, coke, and flux are heated by ascending hot, CO-rich gases that reduce the oxides; and finally the throat, surmounted by a top cone. Blast for the smelting is supplied from adjacent hot stoves. Modern furnaces can operate for about two decades after they are blown-in and before they are left to cool for relining. Molten metal (pig iron) is periodically released through tapholes and removed for casting, and slag is taken out through cinder notches.
Blooms are rolled steel pieces with rectangular profile blooms (typically 40 ×60 cm) that are turned into structural shapes (beams), rails, and pipes.
Carbon appears as an interstitial impurity in iron, forming solid solutions with the three microstructural phases of iron—α-ferrite, δ-ferrite, and γ-ferrite—and combining with iron to form cementite. In low concentrations the element hardens steels, while its higher concentrations in cast iron make the metal brittle. Its removal from cast iron is done through decarbonization.
Cast iron (pig iron) is the name given to a group of metals produced in blast furnaces containing at least 95% and up to more than 97% iron. All of them have high carbon content, at least 1.8% for white cast iron but mostly between 2.5% and 4% for grey cast iron and ductile cast iron. The third most abundant element in unalloyed cast irons is silicon (0.5–3%) and the three elements are forming ternary Fe–C–Si alloy. Pure iron melts at 1523°C, while melting temperatures of different kinds of cast iron are between 1150 and 1200°C. Cast iron usually contains traces of Mn (0.1–1%), S (0.01–0.25%), and P (0.011%). High carbon content makes cast iron brittle and inferior to other common alloys. Cast iron’s tensile strength is just 150–400 MPa, much less than that of bronze or brass; its impact strength is also very low, as is its ductility, but it has good strength in compression.
Cementite is a very hard intermetallic compound (Fe3C, ferric carbide) which makes cast iron hard and brittle.
Continuous casting eliminated energy-wasting batch production, with steel cast first into ingots before its further processing. The idea originated with Henry Bessemer in the 1860s, but it became a commercial reality only during the 1950s, and now virtually all modern steel is cast continuously to produce slabs, blooms, and sheets.
Decarburization (decarbonization) is a process removing carbon from cast iron. This was done traditionally by laborious puddling, since the 1860s it has been accomplished in Bessemer converters. Open hearth furnaces were dominant until after WW II, and now the process is done either in basic oxygen furnaces or in electric arc furnaces.
Direct reduction of iron produces the metal by reacting iron ore (usually pellets) with a reducing agent (most commonly gas) at temperatures below iron’s melting point, yielding solid sponge or briquettes.
Ductility measures the degree to which a material can deform under tensile stress. Ductile (malleable) metals can be hammered out or pressed into sheets, drawn into wires, and molded into shapes. High-strength ductile sheet steel is the most important material for modern car bodies.
Electric arc furnace is a massive tiltable container lined with refractory material whose charge (mostly scrap metal) is heated by an arc between large carbon electrodes inserted through its top. The furnace produces molten steel in batches of tens to hundreds of tonnes after heats typically lasting 30–45 min.
Eutectic point indicates the chemical composition and temperature of the lowest melting point for a mixture of components. Eutectic points of iron–carbon mixtures can be found on liquid–solid phase diagrams (composition on the horizontal axis, temperature on the vertical axis).
Ferrite is a body-centric cubic structure of iron formed as the metal is cooled below 1538°C. Further cooling produces a denser face-centered cubic structure of austenite.
Ferrous alloys are, in the broadest sense, any iron-based alloys including all varieties of steel. According to a narrower definition ferroalloys combine iron with relatively high shares of other elements, including aluminum, chromium, manganese, and silicon.
Flux is crushed limestone or dolomite (or their combination) charged into a blast furnace together with iron ore and coke. Its melting removes sulfur and other impurities from the molten metal, and it forms metallurgical slag.
Impact strength is a standard measure of toughness. The Charpy V-notch test is used to measure energy needed to break a small notched specimen (at a given temperature) by a single impact from a pendulum. The minimal impact energy of steel ranges between 27 and 40 J.
Iron is the most common heavy metal found in the Earth’s crust and its fourth most abundant constituent, following O2, Si, and Al. Iron is also present in the planet’s core, and it reaches us in many meteorites; it is the 26th element of the periodical table, with specific density of 7.87 g/cm3, three times heavier than aluminum but about 12% lighter than copper and 36% lighter than lead. Iron, steels, and cast iron are three types of ferrous alloys; they are defined by their carbon content and by the shares of microstructural forms of iron. There are three principal microstructural components: α-ferrite has a body-centric cubic atomic structure that is stable at ambient temperature and transforms into γ-ferrite at 912°C; δ-ferrite is structurally identical with α-ferrite, but it is stable only at temperatures above 1394°C and it melts at 1538°C; and the γ-ferrite (austenite) phase of carbon steel (up to 2.14% C) can exist only at high temperatures (above 727°C), and it has a face-centered cubic atomic structure. Iron as α-ferrite contains only a negligible trace of carbon (0.008%) at ambient temperature, steels contain 0.008–2.14% C (but usually <1%) by mass and the rest is α-ferrite and cementite, and cast irons have 2.14–6.7% C (but usually <4.5%) by mass, with the rest being cementite.
Martensite is a body-centric tetragonal structure that arises from rapid cooling of austenite. This supersaturated solution of carbon in iron imparts strength and toughness to steel.
Open hearth furnace was a large, shallow basin lined with refractories and covered with a low arched roof. The furnace received molten pig iron, scrap, and fluxing materials and removed excessive carbon during a lengthy per
iod of heating by a gaseous fuel.
Pellets of iron are made from ground iron fines mixed with fluxing materials and binders; coke or coal can also be added to aid the firing process. Pellets with diameters of 9–16 mm are processed in induration machines under temperatures of up to 1350°C.
Pig iron is the term used interchangeably with cast iron: as the International Iron Metallics Association explains, the hot metal was traditionally cast into multiple sand molds branching from a central channel, a configuration resembling a litter of piglets suckling a sow, and after cooling these small ingots (the pigs) were broken off, cooled, and used for further processing (IIMA, 2014).
Plates Flat hot-rolled pieces (2–20 mm thick, up to 1.86 m wide) used to make structural steel products, ship hulls, boilers, pressure vessels, pipes, and various heavy metal structures, including offshore drilling platforms.
Puddling is a labor-intensive and very strenuous process to make wrought iron through decarburization of cast (pig) iron by stirring the hot iron bath and forming heavy balls of malleable metal.
Reduction Removal of oxygen in a chemical reaction. Smelting of ores and production of iron in blast furnaces is the world’s most common chemical reduction. The principal process of direct reduction is Fe2O3 + 3C → 2Fe +3CO, while indirect reduction taking place in a blast furnace proceeds in a series of reactions:
Reinforcing bars Hot-rolled steel pieces cut into various lengths to be used in strengthening concrete in buildings, highways, runways, dams, and bridges.
Reverberatory furnace is designed in such a way that the fuel and the molten metal are separated: usual arrangement is with heat reverberating (reflected from) a low sloping furnace roof and sides.
Rolling is a process that has been used for more than a century to turn steel into semifinished shapes, and now also into finished products. Originally it began with cast steel ingots; now it is a part of continuous casting. Three basic kinds of semifinished products are slabs, billets, and blooms, but continuous casting can also produce thins slabs and thin strips. Rolling can be done hot or cold. Hot-rolled coils are strips 2–7 mm thick and between 0.6 and 1.2 m wide that are used (with or without further processing) in construction, transportation, and pipelines.
Scrap is any metallic waste material suitable for recycling (after sorting and shredding). Steel scrap is the principal feed for electric arc furnaces.
Sections Hot-rolled pieces including beams and sheet piles used in buildings and in industrial and highway construction.
Slabs are wide and thick pieces of steel with rectangular cross-sections, now produced by continuous casting and then converted by further rolling into thin slabs, sheets, plates, pipes, and tubes.
Slag is a by-product of pig iron production, formed by melting iron ore (or its pellets), coke, and a flux (limestone or dolomite) in a blast furnace as lime in the flux combines with the aluminates and silicates in the ore and with coke ash. Molten slag can be cooled in different ways to produce several kinds of solid material used in cement production, in construction, and as a fertilizer.
Steel is, much like coal or crude oil, a singular describing a variety of materials of different compositions and different physical properties. The plural is thus a more accurate choice: steels are ferrous alloys characterized above all by their restricted carbon content, between 0.08% and 2.14% by weight, and high to very high tensile strength and high yield strength and impact strength. The addition of other elements—most commonly Al, Cr, Co, Mn, Mo, Ni, Ti, V, and W, in total amounts ranging from less than 2% to more than 10% of the mass—produces steel alloys with a variety of other desirable properties. Low-carbon sheet steel goes into car bodies, while highly tensile and hardened (with Mn, Mo, and Ni) steels go into axles, shafts, connecting rods, and gear. Stainless steels are indispensable for medical devices and household appliances as well as for chemical and food-processing equipment, and tool steels are made into thousands of devices ranging from chisels and gauges to extrusion dies and sheer blades.
Tensile strength measures the force used to pull a material to the point it can withstand without permanent deformation (yield strength) or to its breaking point (ultimate strength). The two points for structural steel are 250 and 400 MPa; for high-tensile steels they are up to 1.65 and 2.2 GPa.
Tuyère is a water-cooled nozzle (pipe) placed at the top of a blast furnace hearth and used to force blast from hot stoves into the furnace. Tuyères were also used to blow air into Bessemer converters, and they deliver oxygen through the bottom of basic oxygen furnaces.
Wrought iron contains only traces of carbon (0.04–0.08%), but it has inclusions of slag that produce its fibrous or mottled look. The traditional process of producing wrought iron was by decarburization of pig iron. Wrought iron forged (hot-worked) at different temperatures is softer and more malleable than modern steels and also more rust-resistant. In the preindustrial world, the metal was used widely to make items ranging from nails and chains to horseshoes and bolts, and before the adoption of the Bessemer converter to produce cheap steel, it was used to make rails for early railroads (as well as the Eiffel Tower).
Appendix C
Global and National Production of Pig Iron and Steel, 1800–2015
Figure C.1 Pig iron production. Plotted from data in Palgrave Macmillan (2014) and WSA (2014).
Figure C.2 Crude steel production. Plotted from data in Palgrave Macmillan (2014) and WSA (2014).
Appendix D
Production of Crude Steel, 1900–2014 (All figures in Mt/year)
World USA Germany UK Russia Japan China
1900 28 9.2 6.5 5.0 2.2
1910 60 23.7 13.1 6.5 3.3
1920 73 37.8 9.3 9.2 0.2 0.8
1930 95 36.4 12.5 7.4 5.8 2.3
1940 141 78.0 21.5 13.2 18.3 6.9
1950 192 87.8 13.1 16.6 27.3 4.8 0.1
1960 346 90.1 37.9 24.7 65.3 22.1 0.5
1970 595 119.0 50.0 28.3 115.9 93.3 17.8
1980 716 101.0 51.1 11.3 147.9 111.4 37.1
1990 771 89.7 38.4 17.8 154.4 110.3 66.4
2000 850 102.0 30.8 15.2 59.1 106.4 128.5
2010 1430 80.5 43.8 9.7 66.9 109.6 638.7
2013 1642 86.9 42.6 11.9 68.9 110.6 822.7
2014 1662 88.3 42.9 12.1 70.7 110.7 822.7
Source: Palgrave Macmillan (2013); WSA (1982, 2015).
References
1. Adams W, Dirlam JB. Big steel, invention, and innovation. The Quarterly Journal of Economics. 1966;80:167–189.
2. Adriaanse A, Bringezu S, Moriguchi Y, et al. Resource flows: The material basis of industrial economies Washington, DC: World Resources Institute; 1997.
3. Agricola, G. (1556). De re metallica. Basel: Froben. English translation by H. C. Hoover and L. H. Hoover, London: The Mining Magazine (1912).
4. AIG. Infographic: An American bridge’s foreign components. Quartz 2015; May 11, 2015,
5. AISI (American Iron and Steel Institute). (2005). Saving One Barrel of Oil per Ton (SOBOT).
6. AISI. (2009). Steel takes LEED© with recycled content.
7. AISI. (2010). Technology roadmap research program for the steel industry.
8. AISI. (2014). Profile 2014.
9. AISI. (2015). 2015 steel industry profile.
10. Allen RC. International competition in iron and steel, 1850–1913. The Journal of Economic History. 1979;39:911–937.
11. Allen RC. Entrepreneurship and technical progress in the northeast coast pig iron industry: 1850–1913. Research in Economic History. 1981;6:35–71.
12. Almond JK. A centu
ry of basic steel: Cleveland’s place in successful removal of phosphorus from liquid iron in 1879, and development of basic converting in ensuing 100 years. Ironmaking and Steelmaking. 1981;8:1–10.
13. Alstom. (2013). Alstom boilers.
14. Anameric B, Kawatra SK. Direct iron smelting reduction processes. Mineral Processing and Extractive Metallurgy Review: An International Journal. 2015;30:1–51.
15. Antal MJ, Grønli M. The art, science and technology of charcoal production. Industrial and Engineering Chemical Research. 2003;42:1619–1640.
16. Apelt B. The corporation: A centennial biography of United States steel corporation, 1901–2001 Pittsburgh, PA: Cathedral Publishing; 2001.
17. ArcelorMittal. (2014). ArcelorMittal signs a new contract with STX France shipyards for three new cruise ships.
18. ArcelorMittal. (2015). ArcelorMittal.
19. Arens M, Worrell E, Schleich J. Energy intensity development of the German iron and steel industry between 1991 and 2007. Energy Policy. 2012;45:786–797.
20. Arpi G. The supply with charcoal of the Swedish iron industry from 1830 to 1950. Geografiska Annaler. 1953;35:11–27.
21. ASCE (American Society of Civil Engineers). (2015). 2013 Report Card for America’s Infrastructure.
22. Ashkenazi D, Golan O, Tal O. An archaeometallurgical study of 13th-century arrowheads and bolts from the crusader castle of Arsuf/Arsur. Archaeometry. 2013;55:235–257.