Glossary of steel industry terms. logo

Steel Industry Glossary of Terms: I-O.

Technical glossary - jargon made simple

TermGlossary Explanation
IISIInternational Iron & Steel Institute. Former name of World Steel Association (WSA) - one of the leading world steel industry associations
InclusionSteel impurity - most often an oxide or a sulphide - which can have a detrimental impact on mechanical properties
Induction furnaceFurnace is which steel is heated by a process of induction, whereby electromagnetic coils that surround the furnace heat the steel by generation of eddy currents within the metal. Relatively speaking, the process is both very clean with respect to emissions and fairly enegy efficient
IngotMass of metal obtained from casting liquid steel into a mould. The resulting ingot - a semi-finished product - is typically then hot rolled or forged
Interstitial-freeInterstitial-free (IF) steels have few solute interstitial elements, such as carbon and nitrogen. These interstices can be sources of strain and may result in brittleness
IPPCIntegrated Pollution Prevention and Control. To obtain an IPPC permit a business must prove that its applied technologies are equivalent or better than 'best available', as defined by the European Council Directive
Killed steelSteel that has its oxygen content reduced - typically through addition of aluminium. Hence the term aluminium killed
Ladle metallurgyA process step typically applied in a ladle furnace for alloying, deoxidation, desulphurisation as well as for temperature adjustment prior to casting of quality steels
Large diameter pipeDefinition in size terms varies but trade and other statistics frequently define large diameter pipe as over 16 inches (or 406.4mm) in diameter. Large pipe of this size is invariably welded rather than seamless, and can be produced by longitudinal or spiral welding for applications that often include gas and oil transport
LMELondon Metal Exchange - leading non-ferrous metals market in the UK
Long tonMeasure of weight used in the UK prior to metrication. The long ton is equivalent to 2240 pounds or approximately 1016 kg. See also under glossary term short ton and tonne below
Merchant barA category of light long products comprising steel bars shaped as rounds, squares, hexagonals, rectangles, flats etc used mainly as support structures for building, construction, machinery. Merchant bar is to be distinguished from reinforcing bar (which is used to reinforce concrete) and from engineering steel (which often ends up moving rather than being stationery)
MHPTMan hours per tonne - a common measure of labour force or process productivity
Micum indexThe percentages of coke remaining in a given size-band after rotating a coke sample within a drum for a given time. The index is a measure of the strength of coke against both impact and abrasion
Midrex ®Direct reduction process for converting iron ore into direct reduced iron (DRI) for iron and steelmaking
Mild steelLow carbon steel - often also referred to as soft steel. Carbon content generally under 0.25%
Mini millThe term 'minimill' normally refers to a scrap-based EAF route steelmaking operation of relatively small scale (usually less than 500 kt capacity / year; thus much smaller than a typical BOF plant making several million t/yr) producing long products - although the concept is increasingly finding application in flat product mills. The word 'mini' is applied both because of the relatively small scale in volume terms and because of the relatively low capital cost per tonne involved in construction [broadly ~$250/t for a minimill versus ~$1000/t for an integrated plant]
National Allocation Plans, NAPsFacility lists prepared by EU Member States that specify [by country] key installations and their CO2 emission limits
NACEEnd-use industry classification system used in the European Union
NDTNon-destructive testing - refers to electronic or other methods of inspection that do not permanently affect the properties of the material
Nickel pigsIron units made from low grade pig iron produced from laterite ore (0.9% to 1.9% nickel). When the cost of refined nickel rose steeply in 2006, these 'pigs' came into popularity (especially in China) in attempts to offset high stainless steel production costs
NormalisingHeat treatment for relief of internal stress, based on heating and subsequent air cooling
Nut cokeLow ash content coke that is 10-25mm or 12-30mm [industry definitions vary] in size
OCSOrganic coated sheet
OCTGOil country tubular goods - refers to the group of steel tube products (both seamless and welded) used in vertical oil well applications such as casing, drill pipe, and well tubing
OHFOpen hearth steelmaking furnace. A shallow hearth reverberatory furnace in which the charge is melted by flames. Once the most common type of steel making furnace, it has largely been replaced by BOF and EAF steelmaking
OHSOccupational health and safety
Old environmental burdensRefer to liabilities for past environmental damage, often caused during periods of previous State-ownership. In the main, the damage concerns that caused to the soil and to groundwater
Organic coatedOrganic coating refers to paint or varnish which is added as an extra corrosion protection layer to products typically made from zinc-coated sheet

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