Glossary

Special converter for steels resistant to corrosion, acid and heat in which the carbon content is reduced by injecting argon and oxygen. AOD: Abbreviation for argon oxygen decarburization.

With the technology applied at thyssenkrupp, liquid steel is cast between two rotating rolls and then solidifies into a hot strip. Because conventional hot rolling is not required, this saves one entire process step.

Compact ingot made from crude steel. Product of the casting process in a steel mill; used as input stock for the rolling mill to produce hot strips or quarto plates.

Hot-rolled sheets with a minimum thickness of 3 mm. Heavy plates are supplied in all alloyed and unalloyed steel grades.

Equipment for smelting processed iron ore into hot metal. It operates based on the counter-current principle. In other words, the charge (consisting of ore, burden, additives and coke) is supplied from the top – usually from a rotating chute. Wind, preheated in the gas-heated, hot-blast stoves and injected via the bottom tuyeres arranged in a ring over the furnace cross section, flows toward the charge from the opposite direction. Coke serves as a reducing agent. Depending on the charge and the type of operation, various types of pig iron or ferro-alloys can be produced. A furnace remains in operation for many years (furnace campaign). The capacity and cost-efficiency of a blast furnace can be increased by larger furnace units, automatic charge supply, burden preparation, high hot-wind temperatures, oxygen-enriched wind or counter-pressure at the charging door. By-products of the blast furnace are blast furnace gas and blast furnace slag.

A quarter of the blast furnace gas consists of carbon monoxide (CO); it is utilized completely in modern steel mills.

A forming process that takes place following hot rolling or strip casting. In the rolling gap of the cold rolling mill, high pressure is applied to the rolling stock between two rollers to reduce it to a specified thickness. Tandem cold rolling lines for quality steel consist of up to five rolling stands set up in a closely spaced row. It differs from hot rolling based on the temperature. In cold rolling, the rolling temperature is always below the recrystallization temperature, which means that subsequent annealing is always required.

A system in which several process steps take place in one pass; in conventional manufacturing, these steps must be performed one after the other in different units.

Refractory-lined vessel for refining (converting) pig iron into steel. Top-blowing oxygen onto the molten material decreases the carbon content to percentages up to 0.1%.

Abbreviation for physical or chemical vapor deposition.
Surface finishing with metallic, organic or inorganic layers created from precipitation in the vapor phase.

Plant for manufacturing heavy plate with a four-high stand (four rolls).

Used to manufacture sheet steels from wide strip and to cut slit strips to length (slit strip in bars). Straighteners and rolling stands are included along the line. The cut-to-length line is usually positioned parallel to the slitting line.

Reversing stand: A rolling stand that forms rolling stock by passing it back and forth between the adjustable rolls. The equipment consists of one or two rolling stands, where at least one carries out several passes in reverse.

According to DIN EN 10001, pig iron is an alloy of iron and more than 2% carbon (C). It may also contain other elements up to a specified amount. (Mn < 30%, Si < 8%, P < 3%, Cr < 10%, others < 10%). Molten pig iron is processed into steel or cast iron. Steelmaking pig iron is classified into types based on low or high phosphorous content.

Available in liquid or solid form. In either case, it is a crude product. In the liquid state, it is used for the casting of ingots, strands or steel.

During every melting process, a mass of oxides forms, and due to its low specific weight it floats on the hot metal or molten steel. The undesirable by-elements separated from the iron oxide are transferred to the slag. In the solidified state, the structure of the slag is vitreous or stony. Slag from the steelworks is a usable material: blast furnace slag is processed into slag cement (Iron Portland and blast furnace cement), granulated-slag brick, foamed slag, slag lime, road-building materials, track ballast and slag wool. Finely ground converter slag that contains phosphor is a valuable fertilizer.

The sheet or strip is coated by dipping it into a bath of molten metal (e.g. zinc, tin, aluminum, lead or their alloys). Dimensional standard DIN EN 10143.

Also called ladle metallurgy, this is the generic term for all processes used for deoxidation, degassing, alloying, inclusion shape control and improving the degree of steel purity. The majority of these take place in a vacuum.

Close technical cooperation with the automotive industry with regard to material and production-integrated vehicle body development.

In the sintering plant, ore dusts and concentrates are agglomerated into larger pieces. To do so, the fine-grained material, which contains iron oxide, is heated until the surface melts and then “bakes” together.

Fine-grained iron ore is sintered together here with additional materials, coke, additives, etc. “Sintering” is a continuous process for agglomerating ore dust on a sintering belt. This is required because in its original state, the fine-grained ore cannot be used in the blast furnace. It would negatively affect the circulation of gas in the blast furnace.

Materials of particular, documented quality that exceeds the requirements of the standards due to the development work done by the manufacturers.

Wide hot-rolled or cold-rolled strip (rolling width > 600), split by slitting on the slitting line to final strip widths < 600 mm. Delivered in rolls (coils), but also cut to length to strip in bars. The slitting is also used for coated wide strips.

Steel service centers are advanced, highly efficient processing facilities with a comprehensive delivery and service program of slit strips, sheets and blanks in hot-rolled and cold-rolled versions, with surface coating and in stainless steel. They function as a link between roll manufacturers and steel processors.

English term for rust-proof steel.

Device in which the sheets to be hardened are held in place with hydraulically positioned “feet” during the quenching process with pressurized water. (Alternative design: Roll quenching unit. During quenching, the sheet continues to move between guide rollers.)

Furnace for heating up continuous casting segments (slabs) to rolling temperature. The slabs are pushed through the furnace. Alternative design: Walking beam type furnace – here, the slabs are transported through the furnace by lifting them with the walking beams and setting them down further toward the front.

Semi-continuous process for manufacturing slabs from molten steel. In the process, the steel is cast via a distributor into a cooled mold that determines the dimensions (width, thickness) of the slab. Just as the skin is solidifying, the casting strand emerges from the mold, and during further cooling it is guided between rolls, redirected horizontally and cut to the required slab length with a cutting torch.

Supply chain management takes the entire supply chain of a company into consideration with the goal of optimizing the flow of information and material between its internal and external suppliers, its manufacturing area, its distributors and its customers.

A mill in which the rolling stands are arranged in a single row (tandem arrangement). In general, tandem cold strip lines consist of two to five duo, quarto, or sexto stands positioned close together and through which the rolling stock passes once or several times.

Special track-bound transportation containers for hot pig metal. They have a capacity of up to 300 tons of hot metal at a temperature of approx. 1,500°C.

Hot-rolled sheets with tear pattern, used as checker and tear plates.

Type of heat treatment with hardening (quenching at a high temperature) and tempering (annealing at a lower temperature).

Group of steels with high wear resistance when subject to friction or impact due to their microstructure and/or hardness. thyssenkrupp trademark: XAR®.

Hot-rolled product with a rectangular cross-section width of at least 600 mm wound into coils immediately after rolling, edges positioned as close to exactly on top of each other as possible (like a mainspring). Manufactured on hot (wide) strip mills, primarily in a continuous process, in thicknesses of 1.5 to 25.0 mm and widths of up to 2,000 mm. Hot (wide) strip is used as input stock for sheet steel and heavy plates as well as cold (wide) strip.

Production lines for manufacturing hot-rolled strip. Completely continuous mills consisting of one or several roughing stands as well as a finishing mill with seven finishing stands.

Forming process. Rolling at high temperatures enables a large reduction in thickness, e.g. a slab can be formed into thin hot-rolled strip.

Tin-coated, cold-rolled black plate in rated thicknesses of 0.17 to 0.49 mm, double-reduced tinplate from 0.14 to 0.29 mm made of soft, unalloyed steel in accordance with DIN EN 10203. The tin is applied electrolytically on one or both sides in identical or different coating thicknesses. Tin layer increments from 1.0 to 10 g/m² per side. An additional coat of paint may improve corrosion resistance. Mostly used in the packaging industry (with a high recycling rate!), but also for household goods and toys. Technical delivery conditions in DIN 10205.

These steels are characterized by a slight magnetic susceptibility, high permeability and low remagnetization loss. The microstructure should have as few lattice defects and internal stresses as possible in order to make Bloch wall motion easier. Unalloyed or low-alloyed types are used in heavy current engineering. Dynamo and transformer sheet materials are alloyed with Si in order to keep eddy current losses low.

Maximum of the stress-elongation curve determined during tensile testing. Calculated from the quotient of the maximum tensile force and the output cross-section of the sample. Unit: MPa.

Oxide layer that forms on the surface finish during batch annealing, rolling or forging of steel. A scale coat consists of several oxidation layers with differing chemical compositions (rolling skin).

Equipment and operations used to provide steel products with the desired appearance after forming (straightening, cutting, etc.).