steel industry definitions - steelmaking terminology

Glossary Term	Glossary Explanation
Passivation	Changing of a chemically reactive metal surface to a less reactive state, typically through chemical treatment
PCI	Pulverised coal injection - a process increasingly used in blast furnaces, typically offering substantial economic benefits through greater use of coal and proportionately less use of metallurgical coke
Pickling	Removal of mill scale by mechanical and chemical means
Pig iron	A key intermediate material in the integrated (converter-based) steelmaking process, pig iron is the product of smelting iron ore, coke and limestone in a blast furnace. Merchant pig iron is sometimes used as as substitute for scrap in EAF steelmaking, when there is a need to control residuals
Price cycle	Refers to the well-established phenomenon of cyclicality in international steel price movements. Although no cycle is ever identical, this cyclicality has in recent years been characterised by price swings from peak to trough of 25% or more, and by a periodicity (from peak to peak, or trough to trough) of approx. two years
Quenching	Rapid cooling - typically undertaken to obtained a specific property such as increased hardness of steel
REACH	Acronym for 'Registration, Evaluation and Authorisation of Chemicals', an initiative introduced by the European Commission to improve the protection of the environment from chemical hazards
Reduction	Chemical removal of oxygen. Thus direct reduced iron (DRI) is formed through the reduction of iron oxide
Reduction ratio	Typically refers to extent of area compression in the production of hot rolled bar. Reduction ratios of 15:1 used to be the norm for quality applications (e.g. engineering steels) some 10-20 years ago, but even this expectation has fallen with the advent of modern continuous casting practices. Reduction ratios as low as 8:1 are currently acceptable for many high quality long product applications
Residuals	Refer to so-called tramp elements such as copper and tin, which are typically introduced into the steelmaking process in the form of unsorted or contaminated scrap and which can impair the physical and mechanical properties of steel
Refractory	Adjective refers to an ability to retain strength at high temperature. Noun describes the material. In the steel industry, refractory materials are used for furnace linings
SAW	Submerged arc welding - a welding process that uses the heat of an electric arc to melt an electrode held adjacent to a workpiece under a blanket of granular flux [hence 'submerged']
SBQ	Special bar quality - an American term for engineering steel
Scale	Oxide layer which forms on a steel surface at high temperatures
Scarfing	Glossary term describing method for removal of surface blemishes from slab, billet or bloom
Semi	Colloquialism used in reference to semi-finished steel, i.e. ingot, bloom, billet or slab
Sequence casting	Process of casting two or more heats of the same grade of steel in succession through a continuous caster in order to reduce yield losses
Sheet piling	Piling based on use of thin interlocking sheets of steel to obtain a continuous barrier in earth or sand
Short ton	Unit of weight commonly used in the USA and which refers to 2000 pounds. A short ton is equivalent to ~0.907 metric tonnes. See also glossary entry for tonne
Silicon steel	Another term for electrical steel - steel with particular electrical and magnetic properties that makes it especially suited to use in cores of electrical transformers, electrical motors, generators etc
Sintering	A process in which fine materials (typically iron ore fines and coke breeze) are combined into a porous mass that can be used in the blast furnace
Sponge iron	A metallic product made by direct reduction of iron, via the removal of oxygen from iron ore. Sponge iron is also known as DRI, or direct reduced iron
Slab	Semi-finished steel product - the main intermediate material in the production of flat rolled steel. Slab, typically ~150-400 mm thick, is usually hot rolled into plate or into hot rolled coil
SSC	Steel service centre. A typical SSC in the industrialised world may offer customers mechanical services (e.g. cutting, slitting, sawing, shearing, grinding, polishing, drilling, corrugating, edge-shaping, pressing, blanking), advisory services (CAD, material selection, testing, expert technical support) and / or inventory support (bar-coding, storage, JIT, etc)
Stainless	An alloy of carbon and iron that has a minimum chromium content of 10.5 percent
Steckel Mill	Sheet rolling mill that reduces steel gauge by repeated reversal of rolling action. Heated coil boxes at each end allow the steel to be reheated prior to each reversing pass through the Steckel mill's stands
Strand	A combination of individual steel wires that are specially twisted together. Individual strands are often combined in the manufacture of steel rope
Strip mill products	Hot and cold rolled steel coil, sheet and / or strip
Teeming	The pouring of molten metal from a ladle into an ingot mould. The economic advantages of continuous casting over ingot casting mean that the ingot-route process has largely been superseded for high volume production of steel
Terne coated	Cold rolled steel that has been hot dip coated with a lead coating (usually >90% lead). The most common application of terne coated steel is car petrol tanks
Thin slab casting	Production of a slab approx 50 mm - 75 mm thick in a process that is integrated with hot strip casting. The thin slab casting process requires much less gauge reduction of the slab (otherwise undertaken in roughing mills starting with perhaps 250mm thick slab) and the integration with strip rolling means much reduced reheat needs (saving time and energy cost)
TMT	Thermomechanical treatment
Toll rolling	Also refered to as hire rolling this glossary term refers to the practice of rolling steel as a service - typically by a firm that does not have ownership of the steel
Tonne	Unit of weight commonly used outside the USA, which refers to a metric tonne. A tonne is 1000 kilograms or ~2204.6 pounds
Tool steel	Carbon and alloy steels that have high resistance to abrasion. As the name suggests this product group is especially well suited to the manufacture of tools (including stamping dies, shear blades, and hand tools such as spanners, machine tool bit holders etc)
tpt	Tonnes per tonne - refers to process charge as the inverse of yield loss. Thus a charge of 1.05 tpt is the starting weight for a manufacturing step with ~95% through yield
Tundish	A reservoir for holding liquid steel and feeding the steel in a controlled manner into a continuous casting machine
Turnings	Metal shavings formed during the course of metalworking. Also know as swarf

STEEL INDUSTRY GLOSSARY OF TERMS

Technical jargon made simple