Glossary
- This glossary contains explanations of some of the terms and abbreviations you will find on this site. Select the term to show the description.
- advanced high-strength steels (AHSS)
- A series of advanced steels with novel metallurgy and processing compared to conventional high-strength steels. This results in different combinations of higher strength levels, improved formability, and/or increased crash-energy absorption.Advanced high-strength steels are based on a minimum tensile strength of 500 to 800 MPa. Advanced high-strength steels are ideal for crash-energy management, and fatigue and durability sensitive parts. High strength steels enable the use of thinner components, which saves weight and resources.
- alloy; alloying
- A metal that consists of atoms of more than one element. Changing composition and microstructure of alloys enables the targeted engineering of desired material properties.
Alloying is the process of obtaining the desired chemical composition of an alloy.
- austenite
- A homogeneous phase consisting of a solid solution of carbon in the gamma form of iron. It is formed when steel is heated to temperature above the upper critical point. Rapid quenching of the austenite will produce martensite.
- bake hardening
- A change in mechanical properties generally created during a typical automotive paint bake cycle.
- bake hardening steel
- Any high-strength steel that increases in strength as a result of a combination of straining and aging at a temperature and time typical of the automotive paint cure cycle.
- basic oxygen furnace (BOF)
- In the basic oxygen furnace molten iron is made into steel. Oxygen is injected to drive out carbon and other impurities dissolved in the melt. This process generates a lot of heat, so that recycled steel is added to keep the melt at around 1700°C. The resulting crude steel is either further purified or alloyed in subsequent secondary metallurgy processes, or directly brought to the casting process.
- binder
- The part of a forming die that holds the blank by pressure against a mating surface of the die to control metal flow and prevent wrinkling. Also called a blank holder or holddown.
- blast furnace
- The blast furnace is the classical production unit to reduce iron ore to molten iron, called hot metal. It operates as a counter-current shaft system, where iron ore and coke is charged at the top. While this charge descends towards the bottom, ascending carbon containing gases and coke reduces the iron ore to liquid iron. To increase efficiency and productivity, hot air often enriched with oxygen is blown into the bottom of the blast furnace. In order to save coke sometimes coal or other carbon containing materials are injected together with this hot air. The molten iron is tapped at the bottom with a temperature of around 1500 °C. It contains above 4% of carbon. In addition, slag is tapped, which is further used in construction or similar applications. The gases resulting from the chemical reaction of coke and iron ore are collected and used in electricity production or for heating. Modern blast furnaces can produce over 10,000 tonnes of hot metal per day. From this, steel is made, predominantly in the basic oxygen furnace (BOF).
- blast furnace iron (BFI)
- Blast furnace iron (BFI) is iron ore that has been smelted using coke to produce liquid iron. It is often called pig iron although this term is anachronistic ('pig' is an old term for an iron ingot). Today, BFI - also known as liquid iron or hot metal - usually goes directly to the oxygen converter.
In statistics, BFI includes iron from electric pig iron furnaces and the Corex smelting reduction process, because the product is in liquid form.
- burr
- The rough cut edge of metal.
- carbon equivalent
- Various equations that use the percent concentrations of carbon, manganese, chromium and molybdenum (and sometimes other elements) in a steel to predict its weldability.
- casting
- The process of solidifying molten steel. This can be done either continuously (continuous casting) or in a batch process (ingot casting or mould casting). The products obtained from continuous casting are normally slabs, blooms or billets. They are further processed into the desired shape, mainly through rolling processes, to obtain finished steel. Some steel is cast directly into a mould to obtain complex shapes such as turbine housings or engine parts. See also continuous casting.
- clinching
- Mechanical joining systems where the punch forces the two sheets of metal to spread outward in the die and interlock.
- coal
- A natural product containing mainly carbon. The carbon content makes coal very valuable in steelmaking and for many other uses. While most other uses just burn coal to obtain heat, the steel industry uses the chemical ability of carbon to reduce iron ore to iron, from which steel is made. See also metallurgical coal and non-metallurgical coal.
- coke
- A product made by baking coal without oxygen at high temperatures. Unwanted gases are driven out of the coal. (The unwanted gases can be used as fuels or processed further to recover valuable chemicals.) The resulting material (coke) has a strong and porous structure. This makes it ideal for use in a blast furnace. See also coke oven.
- coke oven
- An oven that is used to bake coal without oxygen at high temperatures to form coke. See also coke.
- complex phase (CP) steel
- A steel with a fine microstructure of ferrite and higher volume fractions of hard phases that are further strengthened by fine precipitates.
- computerised forming simulation
- The process of forming a stamping in the computer without construction of hard tooling. The resulting simulation can be used to determine if the initial product design can be formed, evaluate various product and process design options, and obtain additional production requirements such as maximum required press load.
Also known as computerised forming process development.
- continuous casting
- The continuous, high-volume production of metal sections with a constant cross-section. See also casting.
- 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. See also finished steel.
- cup drawing
- A press forming operation in which a cup shaped (often cylindrical) part is produced from a sheet metal blank (often circular in shape).
- die clearance
- The space, on each side, between the punch and die.
- direct reduced iron (DRI)
- Direct reduced iron (DRI) is iron ore that has been reduced using natural gas. The product is solid and in pellet form. Statistically, DRI figures include hot briquetted iron (HBI). HBI is a briquette as opposed to a pellet.
- draw
- A conventional forming operation with continuous blankholder force.
- draw bead
- A ridge constructed around a portion of a die cavity to partially restrain metal flow. A groove in the mating blankholder allows die closing. Sometimes called a die bead.
- dual phase (DP) steel
- A steel consisting of a ferrite matrix containing a hard second phase in the form of islands.
- eco-efficiency
- The term eco-efficiency was coined by the World Business Council for Sustainable Development (WBCSD) in its 1992 publication 'Changing Course'. It is based on the concept of creating more goods and services while using fewer resources and creating less waste and pollution.
- elastic deformation
- Deformation which will return to its original shape and dimensions upon removal of the load or stress.
- elastic limit
- The maximum stress to which a material may be subjected and yet return to its original shape and dimensions upon removal of the stress.
- electric arc furnace (EAF)
- A method of producing steel through the melting of recycled steel and other sources of iron using electricity.
- electrical steel
- A type of steel that exhibits specific magnetic properties, which are required to make transformers, power generators and electric motors. It is mainly obtained by alloying with silicon.
- electro-galvanizing
- The process of dipping steel or steel products into a solution containing the coating metal and applying an electric current. The metal is electro-deposited as a coating on the steel. See also galvanizing and hot-dip galvanizing.
- elongation
- The amount of permanent extension in a tensile test or any segment of a sheet metal stamping.
- embossing
- Displacing a section of metal by a minor amount without noticeable reduction in sheet metal thickness or metal flow from surrounding sheet metal.
- engineering strain
- The unit elongation calculated by dividing the change in length by the original length. Sometimes called the nominal strain.
- engineering stress
- The unit force calculated by dividing the applied load by the original cross-sectional area. Sometimes called the nominal stress.
- Erichsen test
- A test in which a piece of sheet metal, restrained except at the centre, is deformed by a spherical punch until fracture occurs. The height of the cup at fracture is a measure of ductility.
- finished steel
- Steel that is ready to be made into a product (such as cars, cans, ships, and bridges). Finished steels come in a multitude of shapes, sizes, and grades. See also semi-finished steel.
- forming limit curve (FLC)
- An empirical curve showing the levels of different combinations of biaxial strain beyond which failure (local necking) may occur in sheet metal forming. The strains are given in terms of major and minor strains measured from deformed circles previously imprinted as circles into the undeformed sheet metal.
- freshwater
- Water that contains only minimal quantities of dissolved salts, especially sodium chloride, thus distinguishing it from sea water or brackish water.
- galvanizing
- The process of coating steel with a layer of metal, often zinc, but also aluminium or alloys. Such coatings give advanced properties, particularly to protect against corrosion or rusting. See also electro-galvanizing and hot-dip galvanizing.
- gas metal arc welding (GMAW)
- An arc welding process that uses a continuously fed consumable electrode and a shielding gas. Common GMAW processes are metal inert gas (MIG) welding and metal active gas (MAG) welding.
- Gigajoule (GJ)
- One billion (109) joules. A joule is a measure of the energy expended when a force of one Newton moves an object one metre in the direction of the force.
- greenhouse gases
- Gaseous constituents of the atmosphere, both natural and man-made, that absorb and emit radiation at specific wavelengths within the spectrum of infrared radiation emitted by the Earth's surface, the atmosphere and clouds. These gases are often seen as the primary cause of global warming. The main six greenhouse gases covered in the Kyoto Protocol are carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulphur hexafluoride (SF6). Of these gases only carbon dioxide originates from steelmaking in significant amounts. See also Kyoto Protocol.
- heat affected zone
- A zone parall to the weld zone where a change in properties has taken place as a result of the heat generated by the welding process.
- high-strength steel (HSS)
- Any steel product whose initial yield strength is specified between 210 and 550 MPa or whose tensile strength is specified between 270 and 700 MPa. (worldsteel definition)
- home scrap
- Any scrap generated within the steel industry and immediately returned into the steelmaking process. See also scrap.
- hot metal
- The iron produced from a blast furnace in liquid form. In solidified form it is called pig iron.
- hot-dip galvanizing
- A galvanizing process whereby steel is dipped into molten metal. The process can be performed continuously (by running steel strip through the molten metal) or in batches (by dipping complete products such as automobile bodies or gates into a metal bath). See also electro-galvanizing and galvanizing.
- iron ore
- Chemical compounds of iron with other elements, mainly oxygen, silicon, sulphur or carbon. Iron ore is very abundant in the Earth's crust. Only very pure (rich) iron-oxygen compounds are used for steelmaking. Since the iron is chemically bound to the accompanying elements, energy is needed to break these bonds. This makes ore-based steel production more energy intensive than production based on recycled steels, where mainly only melting is required. See also iron ore fines and lump ore.
- iron ore fines
- Iron ore with the majority of individual particles measuring less than 4.75 millimetres in diameter. See also iron ore and lump ore.
- Kyoto Protocol
- An accord reached at a United Nations meeting in Kyoto, Japan, in December 1997 to slow global warming due to the greenhouse effect. Countries agreed on the need for an average 5.2% reduction in the 1990 level of emissions in industrialized countries. The protocol aims to achieve this reduction by 2012. See also greenhouse gases.
- Life Cycle Assessment (LCA)
- A technique to assess the environmental aspects and potential impacts associated with a product, process, or service. Preparing an LCA involves compiling an inventory of relevant energy and material inputs and environmental releases, evaluating the potential environmental impacts associated with identified inputs and releases, and interpreting the results to help make more informed decisions.
- limestone
- A sedimentary rock composed largely of the mineral calcite (calcium carbonate or CaCO3). It is used in the blast furnace to form slags, which are then used in construction and other applications.
- lump ore
- Iron ore with the majority of individual particles measuring more than 4.75 millimetres in diameter. See also iron ore and iron ore fines.
- martensite
- A solid solution of carbon in alpha-iron that is formed when steel is cooled so rapidly that the change from austenite to pearlite is suppressed. Martensite is responsible for the hardness of quenched steel.
- metallurgical coal
- Coal that can be made into coke, which is then used in the blast furnace. See also coal and non-metallurgical coal.
- microstructure
- The arrangement of atoms in a material. Nearly all material properties originate in the microstructure of a material. Steelmaking enables the engineering of a multitude of microstructures leading to thousands of steels with different properties. Each steel is designed to meet the specifications of its user.
- microstructure
- The different phases and structure of metals are shown when a flat ground surface, highly polished, and etched (different enchants for different phases), is magnified and observed in a microscope. A picture of the microstructure is called a photomicrograph.
- mild steel
- Low strength steels with an essentially ferritic microstructure and some strengthening techniques. Drawing quality (DQ) and aluminium killed (AKDQ) are examples of mild steels. They often serve as a reference base because of their widespread application and production volume.
- million metric tons (mmt)
- 1,000,000 x 1,000 kilogrammes = 1 million metric tons. Also known as megatonne (Mt).
- Mpa
- A Pascal (Pa) is the SI (International System of Units) unit of pressure. 1 megapascal (Mpa) = 1,000,000 Pa.
- multiple stage forming
- Forming a stamping in more than one die or one operation. Secondary forming stages can be redraw, ironing, restrike, flanging, trimming, hole expansion and many other operations.
- non-metallurgical coal
- Coal that is suitable for heat and power generation. Non-metallurgical coal can also be injected into the blast furnace to save metallurgical coal. Sometimes called steam coal. See also coal and metallurgical coal.
- obsolete scrap
- Any discarded steel product at the end of its life. See also scrap.
- open-hearth furnace (OHF)
- A vessel used to produce steel, which has been largely superseded by the basic oxygen furnace (BOF). The open-hearth method is about 10 times slower than the BOF.
- pellet
- A small ball of iron ore or limestone particles. See also pelletising.
- pelletising
- The process of rolling iron ore or limestone particles into little balls (or pellets) in a balling drum. The pellets are heated to harden them. The resulting iron ore has the required properties to be used in the blast furnace.
- photomicrograph
- An image of the microstructure of a piece of metal.
- pig iron
- The solidified iron produced from a blast furnace. The traditional moulds for pig iron were formed in sand. They consisted of a shallow central channel with deeper depressions at right-angles to the channel. Hot metal was run along the central channel and filled the deeper depressions, forming ingots of iron. It was thought that the ingots (also called pigs) looked like piglets suckling on their mother. In liquid form, pig iron is known as hot metal.
- prompt scrap
- Scrap generated when making products from steel. It may consist of turnings, cuttings, punchings and borings. Prompt scrap is also known as industrial or new scrap. See also scrap.
- R&D
- Research and development.
- recycled steel
- Steel products at the end of their lifetime. See also scrap.
- residual stresses
- Elastic stresses that remain in the stamping upon removal of the forming load. Sometimes called trapped stresses because the final geometry of the stamping does not allow complete release of all elastic stresses.
- retained austenite
- With proper chemistry and heat treating, some austenite can be retained at room temperature. With sufficient cold work, the retained austenite will transform into martensite.
- scrap
- Steel can be recycled again and again without necessary loss of properties. Scrap is a traditional term for steel products at the end of their lifetime, or for discarded steel during manufacturing stages. Home scrap is any scrap generated within the steel industry and immediately returned into the steelmaking process. Prompt scrap is generated when making products from steel. It may consist of turnings, cuttings, punchings, and borings. Prompt scrap is also known as industrial or new scrap. Obsolete scrap, also referred to as old scrap, is any discarded steel product at the end of its life. All sources of steel scrap are used by the steel industry to ensure that no valuable raw material for steelmaking gets lost.
- secondary steelmaking
- Various treatments that used to make fine adjustments to the composition, temperature, and cleanness of steel made in the BOF or EAF. This may involve alloying, vacuum treatment, special heating, or other sophisticated processes. Not all steels are treated in such a way, many go directly to the casting stage.
- semi-finished steel
- Steel shapes, such as blooms, billets or slabs, that are later rolled into finished steel products such as beams, bars or sheet. Final products (such as cars, cans, ships, and bridges) are made from the finished steel. See also finished steel.
- short ton
- A measure of weight that is equal to 2,000 pounds or 907.18474 kilograms. See also ton and tonne.
- sinter
- Iron ore that has been baked into lumps with coke or coal to ensure it meets the specific properties required for steel production. Recycled iron-containing dust and other residue from the steelmaking process can also be added to the mix. See also sinter plant.
- sinter plant
- The "oven" where iron ore and coke or coal and other residue from the steelmaking process is baked to form sinter. See also sinter.
- slag
- Synthetic rocks that are formed in the blast furnace, basic oxygen furnace, and electric arc furnaces. They result from the non-metallic inclusions and additions into these processes. Solidified slags can be used like rocks or gravel, or they can be used in cement making. Slag can be used in construction or similar applications, where it replaces natural raw materials.
- springback
- The extent to which metal deviates from its designed or intended shape after undergoing a forming operation. Also the angular amount a metal returns toward its former position after being bent a specified amount.
- stainless steel
- Steel alloys that contain high amounts of alloying elements (predominantly more than 10% chromium). Stainless steel resists corrosion, maintains its strength at high temperatures, and is easily maintained. For these reasons, it is used widely in items such as automotive and food processing products, as well as medical and health equipment.
- steel
- An alloy of iron which is malleable (that is, it can be formed by hammering). Steel is not one material, but a whole class of materials, comparable to polymers and plastics. There are between 5,000 and 10,000 different steel grades. They come in any number of shapes, sizes, and finishes. This variety makes steel the basis of our technological civilisation.
- strain rate
- The amount of strain per unit of time.
- stretch flange
- A bending operation in which a narrow strip at the edge of a sheet is bent down (or up) along a curved line that creates stretching (tension) along the length of the flange.
- tensile strength (TS)
- In a tensile test, the strength calculated by dividing the maximum load by the original cross-sectional area.
- ton
- A measure of weight that is equal to 2,240 pounds or 1016.0469 kilograms. Sometimes called a long ton. See also short ton and tonne.
- tonne
- A metric ton (1,000 kilograms). See also ton and short ton.
- transformation induced plasticity (TRIP) steel
- A steel with a microstructure of retained austenite embedded in a primary matrix of ferrite. In addition, hard phases of martensite and bainite are present in varying amounts. The retained austenite progressively transforms to martensite with increasing strain.
- ULSAB - Ultra-light Steel Auto Body
- A joint IISI and motor industry project to holistically design a steel auto-body structure that meets tough structural and crash criteria while weighing 25% less and costing no more than typical vehicles in its class. For more information on this project see worldautosteel.org.
- ULSAB-AVC - Ultra-light Steel Auto Body - Advanced Vehicle Concepts
- A global steel initiative to offer steel solutions to meet society’s demands for safe, affordable, fuel efficient, and environmentally responsible vehicles for the 21st century. For more information on this project see worldautosteel.org.
- ULSAC - Ultra-light Steel Auto Closures
- A joint IISI and motor industry project to develop innovative closure concepts for doors, hoods, deck lids, and hatchbacks. Demonstration door structures are up to 46% lighter than average benchmarked frameless doors. For more information on this project see worldautosteel.org.
- ULSAS - Ultra-light Steel Auto Suspension
- A joint IISI and motor industry project to demonstrate the effective use of steel in producing lightweight, structurally sound steel automotive suspensions that achieve up to 34% mass reductions over conventional steel systems. For more information on this project see worldautosteel.org.
- ultra high-strength steel (UHSS)
- Any steel product whose initial yield strength is specified at 550 MPa or greater or whose tensile strength is specified at 700 MPa or greater. (International Iron and Steel Institute (IISI) definition.)
- yield
- The efficiency of a process by comparing the amount of output to the amount of input. Ferrous yield measures how many iron atoms introduced into the steelmaking process end up as steel product.
- yield strength
- The stress at which a steel exhibits a specified deviation (usually 0.2% offset) from the proportionality of stress to strain.
