Alloying Element
An element added to a metal to effect changes in properties and which remains within the metal.

Blast Furnace
A vertical shaft furnace, equipped with a hot air blast, for producing pig iron from iron ore. The furnace is operated on a continuous basis.

Basic Oxygen Furnace
A large rotatable vessel sometimes called a "converter" or "decarburizing furnace" used to make steel by refining pig iron.

Coke Ovens
Large ovens for heating coal in the absence of air to drive off volatile matter and leave carbon-rich coke as the solid residue. The process results in the production of metallurgical coke and coke breeze, as well as by-products such as tar, gas and aromatic hydrocarbons.

Conditioning
The removal of surface defects from semi-finished steel by chipping, scarfing, grinding or machining to prepare it for further processing.

Continuous Casting
A process for casting molten steel directly into semi-finished shape (e.g. bloom, billet or slab).

Controlled Rolling
A hot rolling process in which the temperature of the steel is closely controlled, particularly during the final rolling passes, to produce a fine-grain microstructure.

Flat Rolled Products
Plate, sheet and strip products of rolling mills equipped with smooth-faced rolls in contrast to grooved or cut rolls used in the manufacture of shapes (e.g. bar).

Flux
Materials (e.g. limestone or dolomite) used in iron and steelmaking furnaces to combine with impurities in the charge and produce a molten slag, which can be separated from the metallic end product. (see limestone)

Formability
The relative ease with which a metal can be shaped through plastic deformation.

Hot Strip Mill
A mill for rolling heated steel slabs through a series of rolling stands to produce sheet steel in coil form.

Limestone
The most common flux, called calcium carbonate (CaCO₃) or more commonly "stone". Used as a flux in the Blast Furnace with dolomite ((Ca,Mg)CO₃). Limestone also has endothermic properties (soaks up heat) and is charged to the BOF vessel as an effective coolant.

Oxygen Lance
A water-cooled steel lance having a copper tip with three 1.3in diameter holes, lowered into the BOF vessels for decarburization of the hot metal. Oxygen is blasted through this lance at a very high velocity (mach 2.3 or 1700 mph), a high flow rate (13000 cfm), and therefore large quantity (1/2 a ton per minute). Cooling water flow rates are 900 gallons per minute.

Pig Iron
The direct metallic product, either solid or molten, of a blast furnace smelting iron ore.

Refractories
Materials used for furnace linings which do not melt at furnace temperatures. They also possess a relatively high degree of resistance to the destructive influences of abrasion, thermal shock, pressure, corrosion and erosion.

Rolling Mill
A rolling mill generally consisting of four horizontal rolls mounted one above the other, revolving at the same speed, but in opposite directions so that the steel to be processed is passed between them. The operation forms the steel into the desired shape and improves its mechanical characteristics. Rolling mills may comprise a series of rolling stands and may be classified by purpose (e.g. Hot Strip Mill) or by design (e.g. four-stand).

Roughing Mill
A rolling mill used for preliminary or initial rolling to shape steel and remove surface scale.

Scale
An oxide of iron formed on steel during hot working or upon exposure to air or steam at elevated temperatures. The scale is normally removed during processing to improve the quality of the final product.

Slab
A semi-finished hot rolled product continuously cast and intended for further rolling into strip or other flat products.

Steel
A malleable alloy of iron and carbon produced by melting and refining pig iron and/or scrap steel. Carbon (in a range from 0.002 to 1.7%) is an essential ingredient but other elements, such as manganese and silicon, may be included to provide specific properties.

Strand Casting
A generic term describing continuous casting of one or more elongated shapes such as billets, blooms or slabs; if two or more strands are cast simultaneously, they are often of identical cross section.

Vacuum Degassing
The processing of molten steel at elevated temperatures in a vacuum. This treatment reduces the content of gases, and reduces the content of unwanted oxides to varying degrees.

Vertical Edger
A vertical rolling unit on a rolling mill for shaping the edges of the product.