The ABC of steel

A

Adjusting ring – A ring-shaped structure which carries the LD-converter shell and allows it to move and tilt

Advanced high-strength steels – Multi-phase steels which contain martensite, bainite and/or retained austenite to achieve an improved balance of strength and formability as compared to conventional high-strength steels

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 or a metal and a non-metal

Alloy steel – An iron-based mixture is considered to be an alloy when minimum quantities of alloying elements are present, e.g. silicon, manganese, chromium, nickel and molybdenum

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 applications; problem solvers and developers

B

Blast furnace – Continuously operating shaft furnace for the reduction of iron ore. The end product in the blast furnace is called pig iron or hot metal

Blast air – Heated air which is blown into the blast furnace under high pressure

C

Carbon dioxide – CO₂, a colorless gas, soluble in water to form carbonic acid; included in carbonated drinks and comprises 0.04% of the atmosphere and is identified as a greenhouse gas

Carbon monoxide – CO, a colorless and odorless energy-rich gas which burns with a blue flame; noxious. Upon combustion, carbon dioxide is formed

Carbon steel – Unalloyed steel

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

Cladding – A covering of a building’s façade that can include solar panels, glass, color coated steel, aluminum, etc. used for new building and renovation construction

Coilbox – Rolling machinery; box for coiled steel employed to promote temperature uniformity during the hot-rolling process

Coiler – Mechanical part which captures strip from the rolling mill and coils it

Coke – Dry distilled coal, the basic fuel consumed in blast furnaces in the reduction of iron ore

Cold-formed steel section – An open steel profile. A steel strip is gradually and continuously cold formed with several rolls into various shapes of cross section. Cold formed steel sections are commonly used in steel frames and structures

Cold rolling – Metalworking process in which the thickness of a sheet, strip or plate is reduced by rolling at ambient temperature

Color coating/Coil Coating – A process where usually cold-rolled and metal-coated strip is additionally coated with an organic paint to improve corrosion protection and achieve a decorative, pleasing appearance

Continuous casting – A process by which molten metal is solidified into a semi-finished billet, bloom, or slab for subsequent rolling

Construction steel – See structural steel

Corrosion protection – The minimization of corrosion by coating with a protective metal

Cowper stoves – Heating apparatus; ceramic towers used for pre-heating blast air, also called hot stoves

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

Dry distillation process – Evaporation of volatile gases from the solid coal by heating the coal in the coking furnaces – two major products are solid coke and coke oven gas

Dual-phase steel (DP) – High-strength steel that has a one soft (ferrite) and one hard (martensite) microstructure which allows for the desired combination of good formability with high strength

E

Electric arc furnace (EAF) – Steelmaking furnace where scrap is generally 100% of the charge. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath

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

Formatting – The cutting of steel plates or sheets into the required customer dimensions

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

Frames – Prefabricated steel frame structures make it possible to create spacious and adaptable interiors. Steel is the perfect choice for strong, light and slender frame structures that are quick and safe to install. Steel frames can be tailored and easily optimized in terms of clear height and column spacing

G

Galvanization – The process of applying a protective zinc coating to steel or iron to prevent rusting or corrosion

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 the collection of molten hot metal

Heated slab – A slab heated to a temperature suitable for hot deformation by, for example, rolling or forging

Heat treatment – Heating and cooling a steel product so as to obtain desired conditions or properties

Hematite – Fe₂O₃, a non-magnetic iron ore or red iron ore

High-strength steels – Steels that can bear high static or dynamic loads without breaking

Hollow section – A circular, square or rectangular tube that can be generally used in welded steel frames. In manufacturing hollow sections, a welded tube goes through a series of shaping stands, which form the round tube into the final square or rectangular shape

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

Hydrogen reduction - the removal of oxygen from ore (for example iron ore - sinter fines, lump or pellets) by reduction with hydrogen gas (producing sponge iron in case of iron ore)

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 thermally processed into hard spheres

L

Ladle – A “bucket” lined with refractory (heat resistant) bricks, used to transport molten steel from process to process in a steel mill

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 (Linz Donawitz) – Oxygen steelmaking process employing a converter (vessel) and top blowing oxygen lance to refine the blast furnace hot metal into crude steel. The name comes from the Austrian cities of Linz and Donawitz

Load-bearing sheets – Load-bearing profiled sheets are made of high-quality raw materials for the roof construction of commercial and industrial buildings. They are a cost-effective roof solution for achieving long spans, which eliminates secondary steelwork. They may also be designed as a stressed skin to distribute horizontal loads to the frame/foundations

Low alloyed steel grades – steel, other than 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, black iron oxide

Martensitic steel – Steel with a very hard form of steel crystalline structure called martensite that is formed by displacive transition. 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

Metal coating – see Hot-dip galvanization

Metallurgy – The science and technology of metals

Microalloying – In the case of advanced fine grain steels with particularly stringent yield strength and tensile strength requirements, small quantities of alloying elements such as niobium, vanadium or titanium are added

Mini-mill - an integrated steel production system, with an integrated electric arc furnace and rolling line to produce ready steel coils without intermediate steps. A mini-mill can use recycled steel and sponge iron in different ratios, depending on the situation.

Mold – Casting mold

N

Niche products – In SSAB’s case, advanced high-strength steels and quenched steels

O

Ore car – Railcar for the 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 (nonmagnetic) 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 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 water – Water from cooling or treatment in the processes. Always undergoes purification and can often be re-circulated

Profiled – Profiled (or corrugated) steel which is pressed in order to corrugate the steel

Protection steel – Structural steel with ballistic properties

Purlin – Purlins are cold-formed open profiles used in construction as a load-bearing element of roofing and cladding

Q

Quenched steels – Hardened and/or tempered steel. SSAB’s quenched steels are also high strength

R

Rain water systems (RWS) – The rainwater systems of a steel roof consist of guttering, downpipes, water tunnels, and other elements to channel rainwater efficiently into the sewer system

Recycling – Return of used products or by-products to enter a new cycle of production and use

Reduction agents – Carbon or hydrogen used to remove oxygen from iron ore to produce iron

Refining – In oxygen-blown steelmaking processes, the reduction of the hot metal’s carbon content during refining by the use of gaseous oxygen

Roll stand – Load-bearing structure in which the rolls are mounted

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

Roofing - A steel roof made of roofing sheets. Usually also includes understructures, rainwater systems, roof safety products, flashings and other elements and accessories

Rougher/Roughing mill – 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

Sandwich panel – Sandwich panels are prefabricated elements that consist of an inner insulation core between two color-coated steel sheet layers. The insulating core can be mineral wool, polyurethane or polystyrene. Sandwich panels are used in façades, partition walls and ceilings. The most typical applications include industrial, office and commercial buildings, sports halls, warehouses and power plants. The panels are also suitable for food industry construction and demanding clean room applications

Scrap – Ferrous (iron-containing) material that generally is re-melted and re-cast into new steel

SEN – Submerged entry nozzle, a ceramic pipe which protects the steel from exposure to air, in conjunction with casting

Sheet pile wall – Long structural sections with a vertical interlocking system that creates a continuous wall. The walls are most often used to retain either soil or water

Shot blasting – Cleaning and descaling metal by means of a stream of abrasive powder or shot. The shot can be sand, small steel balls of various diameters, granules of silicon carbide, etc.

Sintering – A process that combines iron-bearing particles into small pellets

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

Slab – The most common type of semi-finished steel, used for production of flat steel 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

Slitting – A metalworking process involving shearing which is typically employed to cut a wider steel coil into one or more narrower coils

Smelting reduction process – Reduction of iron ore which takes place in a smelting phase

Special steel – Alloyed steel

Sponge iron (DRI) - iron made by the reduction of iron ore and which is used as a raw material in steelmaking, (Direct Reduced Iron), see Hydrogen reduction.

Standard steels – Steels with lower strength (yield strength often 235–355 N/mm²). Used within more conventional applications within the engineering industry and construction sector

Steckel mill – A four-high reversing rolling mill, a 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

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

Strip – Thin, flat steel that resembles hot-rolled sheet, but it is normally narrower and produced to more closely controlled thicknesses

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

Structural steel – Steel intended for, e.g. load-bearing structures, e.g. crane girders. Important qualities include strength, weldability, bendability and toughness

Sulfur purification – Method for removing sulfur from the hot metal or the steel, e.g. through the addition of caustic lime

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 imperfections/flaws such as coil breaks, and to alter mechanical properties

Tempering – Heating to 200–700°C degrees to make steel tougher and less brittle

Tensile strength – Ability to withstand tensile stress. (See Strength)

Thermo-mechanical treatment – A manufacturing method that gives steel the desired strength etc. properties by a careful combination of mechanical work (rolling) and temperature control

Thin plate – A thin plate/sheet 2-15 mm or coil normally produced as a coil in a hot-strip rolling mill and/or further rolled down in a cold-rolling mill

Torpedo – Cylinder-shaped brick-lined railway car used for transporting hot, molten metal

Tube – Round or square tube is made in the same way as pipe. During the manufacturing process, a flat steel strip is gradually forced into shape to become round, and the edges are presented ready to weld. The edges are then welded together to form the tube. In making a square or rectangular cross-section, a welded tube goes through a series of shaping stands, which form the round tube into the final shape

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

W

Wear resistance – Ability to resist the erosion of material from the surface as a result of mechanical action, e.g. abrasion and friction

Wear steel – Steel with qualities adapted to withstand wear, e.g. abrasion