A
After-treatment – Heat treatment, cooling, etc., in order to endow the steel with certain qualities; also galvanizing, organic coating, and cutting to size
Alloy – A substance composed of two or more metals
Alloy Steel – An iron-based mixture is considered to be an alloy steel when manganese is greater than 1.65%, silicon over 0.5%, copper above 0.6%, or other minimum quantities of alloying elements such as chromium, nickel, molybdenum, or tungsten are present. An enormous variety of distinct properties can be created for the steel by substituting these elements in the recipe
Alloying material – Material that is added to the molten metal during the steelmaking process and which combines with iron or other metals and changes the metal's qualities
Annealing – A thermal cycle involving heating to, and holding at a suitable temperature and then cooling at a suitable rate, for such purposes as reducing hardness, improving machinability, facilitating cold working, producing a desired microstructure, or obtaining desired mechanical or other properties
Application – Area of use; a product which uses a certain grade of steel
Applications engineer – Trained specialists in the qualities of the material and its areas of use; problem solvers and developers
B
Base industry – Industry involving the extraction and processing of raw materials; fundamental for the Swedish economy and other economies around the globe
Billet – A semi-finished steel form that is used for “long” products: bars, channels or other structural shapes. A billet is different from a slab because of its outer dimensions; billets are normally 50 to 180 mm square (2 to 7”sq), while slabs are 760 to 3,200 mm (30 to 126”) wide and 50 to 250 mm (2 to 10”) thick. Both shapes are generally continually cast, but they may differ greatly in their chemistry
Blast Furnace – A shaft furnace lined with heat-resistant (refractory) bricks, used by integrated steel mills to reduce and melt iron ore to iron. Its name comes from the “blast” of hot air and gases forced up through the iron ore, coke, and limestone that load the furnace
Blast air – Heated air which is blown into the blast furnace under high pressure
C
Carbon dioxide – CO2, colorless gas, soluble in water to form carbonic acid; included in carbonated drinks and comprises 0.03% of the atmosphere and is identified as a greenhouse gas
Carbon monoxide – Colorless and odorless energy-rich gas which burns with a blue flame; noxious. Upon combustion, carbon dioxide is formed
Charging – The act of loading material into a vessel. For example, iron ore, coke, and limestone are charged into a blast furnace; a basic oxygen furnace is charged with scrap and hot metal, and an electric arc furnace is charged with steel scrap and fluxes
Coil box – Rolling machinery; box for coiled steel employed to promote temperature uniformity during the hot rolling process
Coiler – Mechanical part which captures plate, sheet or strip from the rolling mill and coils it
Coke – Dry distilled coal, the basic fuel consumed in blast furnaces in the smelting of iron ore. Approx. 450 kg (1,000 pounds)) of coke are needed to process a ton of pig iron, an amount which represents more than 50% of an integrated steel mill’s total energy use
Cold rolling – Metalworking process in which the thickness of a sheet, strip or plate is reduced by rolling at ambient temperature
Continuous casting – A process by which molten metal is solidified into a semi-finished billet, bloom, or slab for subsequent rolling
Cowper stoves – Heating apparatus; ceramic towers used for pre-heating blast air
Crude steel – Steel in its solidified state directly after casting. This is then further processed by rolling or other treatments, which can change its properties
Cutting station – Place for cutting the steel strand into slabs
D
Decarburization – In oxygen-blown steelmaking processes, the reduction of the hot metal’s carbon content during refining by the use of gaseous oxygen
Desulphurization – Method for removing sulphur from the hot metal; for example, through the addition of calcium carbide or magnesium oxide
Dry distillation process – Combustion without entry of oxygen
Dual-phase steel (DP) – High-strength steel that has a one soft (ferrite) and one hard (martensite) microstructure which allows for desired combination of good formability with high strength
E
Electric arc furnace (EAF) – Steel-making furnace where scrap is generally 100% of the charge. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath. Furnaces may be either an alternating current (AC) or direct current (DC). DC units consume less energy and fewer electrodes, but they are more expensive
F
Fatigue – The progressive and localized structural damage that occurs when a material is subjected to cyclic loading at stresses considerably below the ultimate tensile strength
Four-high rolling mill – Mechanical equipment; comprises four cylindrical rollers with extremely high pressure which press slabs into plate by repeatedly rolling backwards and forwards
H
Hardening – Process that increases the hardness of steel, i.e. the degree to which steel will resist cutting, abrasion, penetration, bending, and stretching
Hearth – Lower part of the blast furnace; area for collection of molten hot metal
Hematite –Fe2O3, non-magnetic iron ore or blood ore
High-strength steel – Strong steel with high resistance to tensile stress before fatigue and breaking may occur. A very strong steel that is able to withstand high loads before failure
Hot dip galvanization – Method for adding a rust protection surface layer. For example, adding zinc and aluminum in hot molten form on the steel. The opposite to zinc-plating, an electrochemical method of applying a coat of molten zinc to the surface of steel for the purpose of enhancing corrosion resistance
Hot metal – The name for the molten iron produced in a blast furnace. It proceeds to the basic oxygen furnace in molten form or is cast as pig iron
Hot strip rolling mill –A mill for rolling heated slabs through a series of rolling stands to produce sheet steel in coil form
Hot rolling – A metalworking process in which slabs are heated to high temperatures and then deformed between rollers to form thinner cross-sections
I
Injection coal – Coal powder which is injected into the blast furnace under high pressure without being converted to coke
Iron ore pellets – Iron ore particles rolled into small balls and compacted by heating
L
Ladle – A “bucket” lined with refractory (heat resistant) bricks, used to transport molten steel from process to process in a steel plant
Ladle change – Switch from an empty to a full container of steel
Ladle Metallurgy Furnace (LMF) – An intermediate steel processing unit that further refines the chemistry and temperature of molten steel while it is still in the ladle. The ladle metallurgy step comes after the steel is melted and refined in the electric arc or basic oxygen furnace, but before the steel is sent to the continuous caster
Ladle treatment method – Different methods for ladle metallurgy
LD converter – Oxygen steelmaking process employing a converter (vessel) and top blowing oxygen lance to refine the blast furnace hot metal into crude steel. Named for the Austrian towns of Linz and Donawitz, L-D. Often referred to as Basic Oxygen Furnace (BOF) in North America
Low alloyed steel grades – A steel, other than a carbon steel, that requires the minimum content for each specified alloying element to be lower than the applicable limit for the definition for alloy steel
M
Magnetite – Fe3O4, magnetic iron ore
Martensitic steel – Steel with a very hard form of steel crystalline structure called martensite that is formed by displacive transformation. The martensite is formed by rapid cooling (quenching) of austenite which traps carbon atoms that do not have time to diffuse out of the crystal structure
Material design – Control of the steel chemical composition and processing to achieve a microstructure that offers a combination of properties desirable for an intended product or application
Metallurgy – The science and technology of metals – a broad field that includes, but is not limited to, the study of internal structures and properties of metals, and the effects on them of various processing methods
Mold – Casting mold
O
Ore car – Railcar for transportation of lump ore, iron ore concentrate or pellets
Oxide scale – An oxide of iron which forms on the surface of hot rolled steel
Oxygen lance – Pipe-shaped lance for treatment using oxygen
P
Pair of rollers – A pair of cylindrical rollers for rolling steel to thinner dimensions under high pressure
Particulates filter – Purification plant for gas or air in which particulates are separated and condensed for recycling
Phases – Steel has different crystal structures at various temperatures and the phase(s) present depend on heat treatment, alloy quantity, hardening, quenching, etc. Best known are the martensite (quick hardening) phase, ferrite phase (pure iron) austenite (non-magnetic) phase and bainite phase
Pickling line – A processing line which chemically removes oxide or scale from the steel surface to obtain a clean surface for subsequent processing
Plate – Flat rolled steel product which is typically classified as over 1,200 mm (48”) in width and 4.5 mm (0.180”) in thickness
Process gas – Gas from metallurgical processes; often energy rich
Process methods – Methods for extracting raw materials and manufacturing products in a continuous cycle without disruption
Process water – Water from cooling or treatment in the processes. Always undergoes purification and can often be re-circulated
Q
Quenched steels – Hardened or toughened steel. SSAB's quenched steels are also high strength
R
Recycling – Return of used products or byproducts to enter a new cycle of production and use
Reduction agents – Carbon or hydrogen used to remove oxygen from iron ore to produce iron
Rolling mill – Any of the mills in which metal undergoes a rolling process. For plate, sheet and strip, these include the slabbing mill, hot rolling mills, cold rolling mills, and temper mills.. Any operating unit that reduces gauge by application of loads through revolving cylindrical rolls; operation can be hot or cold. The elevated temperature rolling mill is the Hot Mill and is capable of reducing the gauge of a slab 92-99%
Roll pass – Number of times a billet or slab passes through a pair of rollers
Rougher – Two rough cylindrical rollers which press the steel to thinner dimensions prior to hot rolling
Runner – Ceramic-lined spout for controlling molten, hot metal
S
Scrap – Ferrous (iron-containing) material that generally is re-melted and re-cast into new steel. Integrated steel mills use scrap for up to 25% of their basic oxygen furnace charge; electric-arc furnace based steel mills may use scrap for 100% of the furnace charge
SEN – Submerged entry nozzle, a ceramic pipe which protects the steel from exposure to air, in conjunction with casting
Sintering – A process that combines iron-bearing particles, once recovered from environmental control filters, into small pellets. Previously, these materials were too fine to withstand the air currents of the smelting process and were thrown away. The iron is now conserved because the chunks can be charged into the blast furnace
Skirt – Pipe around the blast furnace for the supply and allocation of hot blast air, also known as a bustle pipe
Slab furnace – Furnace for heating steel slabs to rolling temperatures
Slabs – The most common type of semi-finished steel. Traditional slabs can measure 150 to 400 mm thick (6 to 15.7”) and up to 3,200 mm (126”) wide, while the output of the recently developed “thin-slab” casters is approximately 40 to 70 mm (1.6 to 2.7 ”) thick. Subsequent to casting, slabs are sent to the hot-strip mill or plate mill to be rolled into coiled sheet and plate products
Slag – Solution of mainly liquid oxides. Flux such as limestone may be added to foster the congregation of undesired elements into a slag. Because slag is lighter than iron, it will float on top of the pool, where it can be skimmed.
Smelting reduction process – Process for smelting and removing unwanted substances from, for example, metal raw materials
Steckel mill – A four-high reversing rolling mill, the Steckel mill allows the rolling of a large slab by providing heated coil furnaces or boxes on both sides of the mill to store the increased length produced during rolling. These coil furnaces allow for additional heat retention and thermal consistency in the rolled piece, which in turn produces improved uniformity throughout the rolled product
Steel – Alloy of iron and carbon with a carbon content of less than 1.7%
Steel bath – The hot, molten steel in a container
Steel shuttle – Train system for transportation of steel slabs between Luleå, Borlänge and Oxelösund production facilities
Strand – The continuous cast slab within the continuous casting machine prior to cutting into individual slabs
Strength – Properties related to the ability of steel to oppose applied forces. Forms of strength include withstanding imposed loads without a permanent change in shape or structure and resistance to stretching
Structure – The steel's molecular form following different treatment methods; crystalline structure. May also refer to the size, shape, and arrangement of phases within the steel
Strip – Thin, flat steel that resembles hot-rolled sheet, but it is normally narrower (up to 300 mm, or 12” wide) and produced to more closely controlled thicknesses. Strip also may be cut from steel sheet by a slitting machine
Surface treatment – Cleaning, polishing or coating of surfaces; for example, through galvanization or organic coating
T
Temper Mill – A type of cold-rolling mill, usually a four-high, single stand mill, used to provide a relatively light cold rolling reduction to hot rolled, cold rolled, or coated flat steel products to improve flatness, minimize surface disturbances such as coil breaks, and to alter mechanical properties
Tempering – Heating to 200-500°C degrees in order to make steel tougher and less brittle
Tensile strength – Ability to withstand tensile stress. (See Strength)
Torpedo – Cylinder-shaped brick-lined railway car used for transporting hot, molten metal
Tundish – An intermediate container in the casting process to facilitate ladle change without disruption in the process
V
Vacuum Degassing – An advanced steel refining facility that removes oxygen, hydrogen and nitrogen under low pressures (in a vacuum) to produce high quality steel for demanding applications. Normally performed in the ladle, the removal of dissolved gases results in cleaner, higher quality, more pure steel (see Ladle Metallurgy)
W
Wear resistance – Ability to resist the erosion of material from the surface as a result of mechanical action, e.g. abrasion and friction