Definitions of Phrases and Terms used in Steelmaking

Alloy Steels

A substance composed of two or more metals, or of a metal and a non-metal, fused together. In case of steel, elements such as nickel, boron and vanadium are added to steel to improve certain characteristics such as malleability, strength, ductility and elongation.

Billets

A Semi-Finished steel form with a square cross section and different lengths. This is a product of casting process where molten steel is solidified by cooling. Billets are further processed by rolling to obtain finished Long Products like wire rod and rebars.

Blast Furnace

A furnace used in conventional integrated steel making in which coke and iron ore react together under a hot air flow to form liquid metal. It is basically a large cylinder, lined with heat-resistant refractory bricks.

Bundle

A group of steel bars or flat sheets arranged and tied together to facilitate handling.

Burnt Lime

The product of burning (calcining) lime stone which is necessary in the steel making to make slag.

Carbon Steel

Carbon steels is the result of combining iron and carbon. It contains trace amounts of alloying elements and account for 90% of total steel production. Its properties are dependent on the percentage of carbon present.

Caster

A machine used to mould liquid steel into its first solid shapes: Slabs, blooms, or Billets which are Semi-Finished steel products that are further processed (rolled) into finished products.

Charge

Charging is the act of loading material into a vessel.  In this respect, the loaded materials are called the “Charge”. For example, Direct Reduced Iron, Scrap, Coke and Burnt Lime comprise the “charge” of an Electric Arc Furnace.

Coil

A finished long or flat steel product, such as wire rod or strip respectively, which has been wound or coiled after rolling.

Cold Rolled Coil

Flat rolled products for which the required final thickness is obtained by rolling at room temperature.

Cold Rolling

The passing of Sheet or Strip that has previously been Hot Rolled and pickled through Cold Rolls, i.e. below the softening temperature of the metal. Cold rolling makes a product thinner, smoother, and stronger than can be made by Hot Rolling alone.

Compact Strip Production (CSP)

Compact Strip Production (CSP) is a novel technology developed in 1980s by SMS-Germany for casting-and-hot-rolling of thin slabs.  Unlike the conventional rolling mills where casting and rolling are two independent or separate processes, this new technological innovation provides a more compact production line and a simpler procedure by integrating Thin Slab Casting with Hot Rolling in one continuous process.

Continuous Casting

A process for solidifying steel in the form of a continuous Strand rather than individual ingots. Molten steel is poured into open-bottomed, water-cooled moulds. As the molten steel passes through the mould, the outer shell solidifies. After exiting the mould, spraying water directly onto the formed shell helps complete the solidification of the whole cross section of the billet, bloom or slab.

Crude Steel

Steel in the first solid state after melting, suitable for further processing or for sale. Synonymous to raw steel.

Cut-to-Length Line

The line where the flat steel coil is uncoiled and transversely cut into rectangular sheets. The sheets are then arranged and strapped in the form of bundles.

Direct Reduction

A family of processes for making iron from ore without approaching the melting temperature. No Blast Furnace is needed. The process of removing the oxygen from the Iron Ore pellets or lumps by reducing gases, such as Carbon Monoxide and Hydrogen, takes place while the iron ore remains in the solid state, thus producing Direct Reduced Iron (DRI) which is a purer form of iron.

Direct Reduced Iron (DRI)

Processed iron ore that is iron-rich enough to be used as a scrap substitute in electric furnace steelmaking. Enabling the mini-mills to use iron ore without the blast furnace, DRI can serve as a low residual raw material and alleviate the mini-mills' dependence on higher-priced scrap. DRI is only economically feasible in regions where natural gas is available and attractively priced.

Direct Reduction Plant (DRP)

A plant that processes Iron Ore to produce Direct Reduced Iron. (See: “Direct Reduction” and “Direct Reduced Iron”).

Electric Arc Furnace

A furnace used normally for both scrap and DRI-based steel making. Once the furnace is Charged and covered, graphite electrodes are lowered through holes in the roof. The electric arc traveling between the electrodes and the metallic Charge creates intense heat, which melts the Scrap and DRI. Alloying elements can be added during this process, or later on in case there is ladle furnace employed.

Ferroalloys

A metal product commonly used as an additive in steelmaking, rich in at least one alloying element (e.g. Manganese, Silicon, Chromium) and containing iron. It is used to aid various stages of the steelmaking process such as deoxidation, desulphurization, and adding strength. Examples: ferromanganese, and ferrosilicon, and ferrochromium.

Ferrous Scrap

Scrap of materials consisting mainly of iron.

Flat Products

A term referring to a class of products with a flat surface. These include Sheet, Strip and Plate that are either hot rolled from Slabs, or cold-rolled from previously Hot Rolled Coils.

Flexible Thin slab casting and rolling (fTSCR)

Danieli’s flexible thin slab caster is a combined casting and rolling process of flat steel in one continuous line, unlike the conventional rolling mills where casting and rolling are two independent or separate processes.

Graphite Electrodes

The electricity conducting poles used in Electric Arc Furnace to generate the arc whose high heat cause the ferrous charge (scrap and/or DRI) to melt.

Heat

The production batch of a steel making facility (e.g. Electric Arc Furnace) is called a “Heat”. Every heat can have its own chemical composition according to the aimed steel grade.

Heavy Cut-to-Length Line

The line where flat steel coils of relatively thicker thicknesses (e.g. more than 5.00 mm) are cut into sheets.

Hot Rolled Coil (HRC)

Flat steel products that are brought to final thickness by rolling through a Hot Strip Mill at high temperatures.

Hot Rolling

The act of rolling semi-finished steel (e.g. billet or slab) after it has been reheated into Long or Flat Products.

Hot Strip Mill (HSM)

In the hot strip mill, slabs coming from the continuous caster are rolled out to steel strips with a flat surface and a thickness from about 1.0 to 14.0mm.

Integrated Management System (IMS)

Combines all related components of a business into one system for easier management and operations. Quality, Environmental, and Safety management systems are often combined and managed as an IMS.

Integrated Steelmaker

A producer that converts iron ore into semi-finished or finished steel products. Traditionally, this process required coke ovens, blast furnaces, steelmaking furnaces, and rolling mills. A growing number of integrated mills use the direct reduction process to produce sponge iron without coke ovens and blast furnaces.

International Organization for Standardization (ISO)

ISO is an independent, non-governmental international standard setting organization with a membership of 162 national standards bodies.

Iron Ore

The primary iron-borne raw material in the manufacture of steel. It may be in the form of lumps (i.e. as extracted from the mines) or can be further processed in the form of pellets.

Ladle Furnace

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

It is a large cylindrical vessel where the molten steel from the steel making facility (e.g. Electric Arc Furnace) is tapped (poured). Further metallurgical treatment of steel and temperature adjustment can take place in the ladle before carrying it to the casting machine.

Light Cut-to-Length Line

The line where flat steel coils of relatively thinner thicknesses (e.g. up to 5.00 mm) are cut into sheets.

Limestone

Material used by the steel industry (as it is or after being calcined into Burnt Lime) to remove impurities from the iron. Magnesium-containing limestone, called dolomite, is also sometimes used in the purifying process.

Lime Stone

The naturally formed material in the form of Calcium Carbonate found in quarries.

Lime Calcining

The process of burning lime stone or dolomite to produce burnt lime or burnt dolomite.

Long Products

Steel that comes in long shapes such as Beams, Rebars and Wire Rods:

• Beams & Rebars are typically used in construction.
• Merchant bars are used in manufacturing, construction and ornamentation.
• Wire Rods are used in nails, construction and to make different types of wires and wire-based products.

Lump Ore

It is the form of iron ore with irregular shapes as extracted from mines without further processing.

Pellets

An enriched form of iron ore processed and shaped into small balls.

Pickling Line

The line used to remove the scale layer from the surface of hot-rolled coils through passing the strip in hydrochloric acid baths.

Plate

A flat rolled product rolled from slabs or ingots, of greater thickness than Sheet or Strip.

Rebar (Reinforcing Bar)

A commodity-grade steel used to strengthen concrete in construction.

Rolling Mill

Equipment that reduces and transforms the shape of semi-finished or intermediate steel products by passing the material through a gap between rolls that is smaller than the entering materials.

Semi-Finished Products

Products such as slabs, billets, and blooms which must be rolled or otherwise processed to create usable steel shapes.

Sheet

A flat rolled product over 12 inches in width and of less thickness than plate.

Skin Pass Mill

The mill used to improve the mechanical properties, flatness, and surface texture of hot-rolled coils.

Slab

A wide semi-finished product made from an ingot or by continuous casting. Flat steel products are made from slabs.

Slag

A by-product of melting iron-borne materials (e.g. scrap, DRI) with limestone or burnt lime that floats on the surface of liquid steel. Processed cold slag is usually recycled to make concrete and road building materials.

Sponge Iron

The product of the direct reduction process. Also known as direct reduced iron (DRI).

Steel Grade

The mechanical properties (e.g. tensile strength, yield strength, elongation), physical properties, and/or chemical properties (amount of carbon, levels of impurities, alloying elements) determine the properties of each steel grade.

Strip

A flat-rolled product customarily narrower in width than sheet, and often produced to more closely controlled thicknesses.

Steel Service Centre

The center where the hot rolled coils are further adapted to the needs of end users in terms of weight, shape and dimensions. It may include processing facilities such as slitting and cut-to-length lines.

Slitting Line

The line where the flat steel coil is uncoiled and longitudinally slit into narrower widths coils.

Tapping

The act of pouring the liquid steel from the steelmaking facility (e.g. Electric Arc Furnace) to the Ladle.

Tap-to-Tap Time

The time elapsed between the start of tapping of a heat from the Electric Arc Furnace and the start of tapping of the following heat.

Ton (T)

A metric ton, equivalent to 1,000 kilograms or 2,204.6 pounds or 1.1023 short ton.

Tundish

It is the intermediate vessel used to deliver liquid steel from a ladle to the mould evenly and at a designed throughput rate and temperature without causing contamination of steel by inclusions. It also helps make the process of continuous casting possible as it acts as a reservoir of liquid steel during the period of ladle change where it continues to supply liquid steel to the moulds.

Wire Rod

Coiled bars of up to 18.5mm in diameter, used mainly in the construction, and the production of wire and nails.