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صنعت فولاد - لغات و اصطلاحات صنعت فولاد

لغات و اصطلاحات صنعت فولاد

چهارشنبه 24 آذر 1389 02:54 ب.ظ

نویسنده : علی فروزان
Iron & Steel Industry Glossary

A
Agglomerating Processes

Fine particles of limestone (flux) and iron ore are difficult to handle and transport because of dusting and decomposition, so the powdery material usually is processed into larger pieces. The raw material's properties determine the technique that is used by mills.

Sinter - Baked particles that stick together in roughly one-inch chunks. Normally used for iron ore dust collected from the blast furnaces.

Pellets - Iron ore or limestone particles are rolled into little balls in a balling drum and hardened by heat.

Briquettes - Small lumps are formed by pressing material together. Hot Iron Briquetting (HBI) is a concentrated iron ore substitute for scrap for use in electric furnaces.

Alloying Element
Any metallic element added during the making of steel for the purpose of increasing corrosion resistance, hardness, or strength.
 

Alloy Steel
An iron-based mixture is considered to be an alloy steel when manganese is greater than 1.65%, silicon over 0.5%, copper above 0.6%, or other minimum quantities of alloying elements such as chromium, nickel, molybdenum, or tungsten are present. An enormous variety of distinct properties can be created for the steel by substituting these elements in the recipe.
 

Alloy Surcharge
The addition to the producer's selling price included in order to offset raw material cost increases caused by higher alloy prices.
 

American Petroleum Institute (API)
Oil trade organization (founded in 1920) that is the leading standardizing organization for oilfield drilling and producing equipment.
 

Annealing
A heat or thermal treatment process by which a previously cold-rolled steel coil is made more suitable for forming and bending. The steel sheet is heated to a designated temperature for a sufficient amount of time and then cooled.

The bonds between the grains of the metal are stretched when a coil is cold rolled, leaving the steel brittle and breakable. Annealing "recrystallizes" the grain structure of steel by allowing for new bonds to be formed at the high temperature.

There are two ways to anneal cold-rolled steel coils; batch and continuous.

1) Batch (Box). Three to four coils are stacked on top of each other, and a cover is placed on top. For up to three days, the steel is heated in a non-oxygen atmosphere (so it will not rust) and slowly cooled.

(2) Continuous. Normally part of a coating line, the steel is uncoiled and run through a series of vertical loops within a heater: The temperature and cooling rates are controlled to obtain the desired mechanical properties for the steel.
 

API-certified
Said of a tool that meets the American Petroleum Institute's minimum standards.
 

Automatic Gauge Control
Using hydraulic roll force systems, steelmakers have the ability to control precisely their steel sheet's gauge (thickness) while it is traveling at more than 50 miles per hour through the cold mill. Using feedback or feed-forward systems, a computer's gap sensor adjusts the distance between the reduction rolls of the mill 50-60 times per second. These adjustments prevent the processing of any off-gauge steel sheet.
 

B
Basic Oxygen Furnace (BOF)
A pear-shaped furnace, lined with refractory bricks, that refines molten iron from the blast furnace and scrap into steel. Up to 30% of the charge into the BOF can be scrap, with hot metal accounting for the rest.

BOFs, which can refine a heat (batch) of steel in less than 45 minutes, replaced open-hearth furnaces in the 1950s; the latter required five to six hours to process the metal. The BOF's rapid operation, lower cost and ease of control give it a distinct advantage over previous methods.

Scrap is dumped into the furnace vessel, followed by the hot metal from the blast furnace. A lance is lowered from above, through which blows a high-pressure stream of oxygen to cause chemical reactions that separate impurities as fumes or slag. Once refined, the liquid steel and slag are poured into separate containers.
 

Bars
Long steel products that are rolled from billets. Merchant bar and reinforcing bar (rebar) are two common categories of bars, where merchants include rounds, flats, angles, squares, and channels that are used by fabricators to manufacture a wide variety of products such as furniture, stair railings, and farm equipment. Rebar is used to strengthen concrete in highways, bridges and buildings (see Sheet Steel).
 

Billet
A solid steel cylinder used to produce seamless tubular products. The billet is pierced lengthwise to form a hollow tube that is shaped and sized to produce the tubular product.
 

Black Plate
Cold-reduced sheet steel, 12-32 inches wide, that serves as the substrate (raw material) to be coated in the tin mill.
  

Blast Furnace
A towering cylinder lined with heat-resistant (refractory) bricks, used by integrated steel mills to smelt iron from its ore. Its name comes from the "blast" of hot air and gases forced up through the iron ore, coke and limestone that load the furnace.
 

Blanking
An early step in preparing flat-rolled steel for use by an end user. A blank is a section of sheet that has the same outer dimensions as a specified part (such as a car door or hood) but that has not yet been stamped. Steel processors may offer blanking for their customers to reduce their labor and transportation costs; excess steel can be trimmed prior to shipment.
 

Bloom
A semi-finished steel form whose rectangular cross-section is more than eight inches. This large cast steel shape is broken down in the mill to produce the familiar I-beams, H-beams and sheet piling. Blooms are also part of the high-quality bar manufacturing process: Reduction of a bloom to a much smaller cross-section can improve the quality of the metal.
 

Breakout
An accident caused by the failure of the walls of the hearth of the blast furnace, resulting in liquid iron or slag (or both) flowing uncontrolled out of the blast furnace.
 

Burr
The very subtle ridge on the edge of strip steel left by cutting operations such as slitting, trimming, shearing, or blanking. For example, as a steel processor trims the sides of the sheet steel parallel or cuts a sheet of steel into strips, its edges will bend with the direction of the cut (see Edge Rolling).
 

Busheling
Steel scrap consisting of sheet clips and stampings from metal production. This term arose from the practice of collecting the material in bushel baskets through World War II.
 

Butt-Weld Pipe
The standard pipe used in plumbing. Heated skelp is passed continuously through welding rolls, which form the tube and squeeze the hot edges together to make a solid weld.
 

C
Capacity

Normal ability to produce steel in a given time period. This rating should include maintenance requirements, but because such service is scheduled to match the needs of the machinery (not those of the calendar), a mill might run at more than 100% of capacity one month and then fall well below rated capacity as maintenance is performed.

Engineered Capacity - The theoretical volume of a mill, given its constraints of raw material supply and normal working speed.

True Capacity - Volume at full utilization, allowing for the maintenance of equipment and reflecting current material constraints. (Bottlenecks of supply and distribution can change over time and capacity will expand or reduce.)
 

Carbon Steel
Steel that has properties made up mostly of the element carbon and which relies on the carbon content for structure. Most of the steel produced in the world is carbon steel.
 

Casing
Casing is the structural retainer for the walls of oil and gas wells, and accounts for 75% (by weight) of OCTG shipments. Casing is used to prevent contamination of both the surrounding water table and the well itself. Casing lasts the life of a well and is not usually removed when a well is closed.
 

Charge
The act of loading material into a vessel. For example, iron ore, coke and limestone are charged into a Blast Furnace; a Basic Oxygen Furnace is charged with scrap and hot metal.
 

Circored®
A gas-based process developed by Lurgi Metallurgie in Germany to produce Direct Reduced Iron or Hot Briquetted Iron.

The two-stage method yields fines with a 93% iron content. Iron ore fines pass first through a circulating fluidized-bed reactor, and subsequently through a bubbling fluidized-bed reactor.
 

Cladding
Method of applying a stainless steel coating to carbon steel or lower-alloy steel (i.e., steel with alloying element content below 5%).

Why: To increase corrosion resistance at lower initial cost than exclusive use of stainless steel.

How: By (1) welding stainless steel onto carbon steel, (2) pouring melted stainless steel around a solid carbon steel slab in a mold, or (3) placing a slab of carbon steel between two plates of stainless steel and bonding them by rolling at high temperature on a plate mill.
 

Coils
Steel sheet that has been wound. A slab, once rolled in a hot-strip mill, is more than one-quarter mile long; coils are the most efficient way to store and transport sheet steel.
 

Coke
The basic fuel consumed in blast furnaces in the smelting of iron. Coke is a processed form of coal. About 1,000 pounds of coke are needed to process a ton of pig iron, an amount which represents more than 50% of an integrated steel mill's total energy use.

Why: Metallurgical coal burns sporadically and reduces into a sticky mass. Processed coke, however, burns steadily inside and out, and is not crushed by the weight of the iron ore in the blast furnace.

How: Inside the narrow confines of the coke oven, coal is heated without oxygen for 18 hours to drive off gases and impurities.
 

Cold Reduction
Finishing mills roll cold coils of pickled hot-rolled sheet to make the steel thinner, smoother, and stronger, by applying pressure, rather heat. Stands of rolls in a cold-reduction mill are set very close together and press a sheet of steel from one-quarter inch thick into less than an eighth of an inch, while more than doubling its length.
 

Cold-Rolled Strip (Sheet)
Sheet steel that has been pickled and run through a cold-reduction mill. Strip has a final product width of approximately 12 inches, while sheet may be more than 80 inches wide. Cold-rolled sheet is considerably thinner and stronger than hot-rolled sheet, so it will sell for a premium (see Sheet Steel).
 

Cold Working (Rolling)
Changes in the structure and shape of steel achieved through rolling, hammering, or stretching the steel at a low temperature (often room temperature).

Why: To create a permanent increase in the hardness and strength of the steel.

How: The application of forces to the steel causes changes in the composition that enhance certain properties. In order for these improvements to be sustained, the temperature must be below a certain range, because the structural changes are eliminated by higher temperatures.
 

Consumption
Measures the physical use of steel by end users. Steel consumption estimates, unlike steel demand figures, account for changes in inventories.

Apparent Supply: Derived demand for steel using AISI reported steel mill shipments plus Census Bureau reported imports, less Census Bureau reported exports. Domestic market share percentages are based on this figure, which does not take into account any changes in inventory.
 

Continuous casting
A method of pouring steel directly from the furnace into a billet, bloom, or slab directly from its molten form.

Why: Continuous casting avoids the need for large, expensive mills for rolling ingots into slabs. Continuous cast slabs also solidify in a few minutes versus several hours for an ingot. Because of this, the chemical composition and mechanical properties are more uniform.

How: Steel from the BOF or electric furnace is poured into a tundish (a shallow vessel that looks like a bathtub) atop the continuous caster. As steel carefully flows from the tundish down into the water-cooled copper mold of the caster, it solidifies into a ribbon of red-hot steel. At the bottom of the caster, torches cut the continuously flowing steel to form slabs or blooms.
 

Contract Sales
Steel products committed to customers through price agreements extending 3-12 months. About one-half of all flat-rolled steel is sold on this basis, primarily because the auto companies sign agreements to cover at least one year's model. Price increases that the steel mills might announce during the year do not generally affect the revenues from the contract side of the business.
 

Conversion Cost
Resources spent to process material in a single stage, from one type to another. The costs of converting iron ore to hot metal or pickling hot-rolled coil can be isolated for analysis.
 

Converter/Processor
Demand from steel customers such as rerollers and tube makers, which process steel into a more finished state, such as pipe, tubing and cold-rolled strip, before selling it to end users. Such steel generally is not sold on contract, making the converter segment of the mills' revenues more price sensitive than their supply contracts to the auto manufacturers.
 

COREX®
COREX is a coal-based smelting process that yields hot metal or pig iron. The output can be used by integrated mills or EAF mills. The process gasifies non-coking coal in a smelting reactor, which also produces liquid iron. The gasified coal is fed into a shaft furnace, where it removes oxygen from iron ore lumps, pellets or sinter; the reduced iron is then fed to the smelting reactor.
 

Corrosion
The gradual degradation or alteration of steel caused by atmosphere, moisture, or other agents.
 

Coupling
In piping, a metal collar with internal threads used to join two sections of threaded pipe.
 

Culvert Pipe
Heavy gauge, galvanized steel that is spiral-formed or riveted into corrugated pipe, which is used for highway drainage applications.
 

Cut-to-Length
Process to uncoil sections of flat-rolled steel and cut them into a desired length. Product that is cut to length is normally shipped flat-stacked.
 

D
Desulfurization
Operation that injects a chemical mixture into a ladle full of hot metal to remove sulfur prior to its charging into the Basic Oxygen Furnace. Sulfur enters the steel from the coke in the blast furnace smelting operation, and there is little the steelmaker can do to reduce its presence. Because excess sulfur in the steel impedes its welding and forming characteristics, the mill must add this step to the steelmaking process.
 

Direct Reduced Iron (DRI)
Processed iron ore that is iron-rich enough to be used as a scrap substitute in electric furnace steelmaking.

Why: As mini-mills expand their product abilities to sheet steel, they require much higher grades of scrap to approach integrated mill quality. Enabling the mini-mills to use iron ore without the blast furnace, DRI can serve as a low residual raw material and alleviate the mini-mills' dependence on cleaner, higher-priced scrap.

How: The impurities in the crushed iron ore are driven off through the use of massive amounts of natural gas. While the result is 97% pure iron (compared with blast furnace hot metal, which, because it is saturated with carbon, is only 93% iron), DRI is only economically feasible in regions where natural gas is attractively priced.
 

Drawn-Over-Mandrel
A procedure for producing specialty tubing using a drawbench to pull tubing through a die and over a mandrel, giving excellent control over the inside diameter and wall thickness. Advantages of this technique are its inside and outside surface quality and gauge tolerance. Major markets include automotive applications and hydraulic cylinders.
 

Drill Pipe
Pipe used in the drilling of an oil or gas well. Drill pipe is the conduit between the wellhead motor and the drill bit. Drilling mud is pumped down the center of the pipe during drilling, to lubricate the drill bit and transmit the drilled core to the surface. Because of the high stress, torque and temperature associated with well drilling, drill pipe is a seamless product.
 

Ductility
Ability of steel to undergo permanent changes in shape without fracture at room temperature.
 

Dumping
Dumping occurs when imported merchandise is sold in, or for export to, the domestic market at less than the normal value of the merchandise, i.e., a price which is less than the price at which identical or similar merchandise is sold in the comparison market, the home market (market of exporting country) or third-country market (market used as proxy for home market in cases where home market cannot be used). The normal value of the merchandise cannot be below the cost of production.
 

Dumping Margin
The amount by which the normal value exceeds the export price or constructed export price of the subject merchandise.
 

E
Edge Rolling (Edge Conditioning)
Rolling a strip of steel to smooth the edges. By removing the burr off the coil, it is safer for customers to manipulate.
 

Electric Arc Furnace (EAF)
Steelmaking furnace where scrap is generally 100% of the charge. Heat is supplied from electricity that arcs from the graphite electrodes to the metal bath. Furnaces may be either an alternating current (AC) or direct current (DC). DC units consume less energy and fewer electrodes, but they are more expensive.
 

Electric Resistance Welded (ERW) Pipe
Pipe made from strips of hot-rolled steel which are passed through forming rolls and welded. While seamless pipe is traditionally stronger and more expensive than comparable ERW pipe, ERW technology is improving.
 

Electrical Steel
(See Silicon Electrical Steel)

F
Fabricator
A producer of intermediate products that does not also produce primary metal. For example, a rebar (see Reinforcing Bar) fabricator purchases rebar and processes the material to the specifications of a particular construction project.
 

Fastmet
A process to directly reduce iron ore to metallic iron pellets that can be fed into an electric arc furnace with an equal amount of scrap. This process is designed to bypass the coke oven-blast furnace route to produce hot metal from iron ore. It is also one of several methods that mini-mills might use to reduce their dependence on high-quality scrap inputs (see Direct Reduced Iron and Hot Briquetted Iron).
 

Feedstock
Any raw material.
 

Ferroalloy
A metal product commonly used as a raw material feed in steelmaking, usually containing iron and other metals, to aid various stages of the steelmaking process such as deoxidation, desulfurization, and adding strength. Examples: ferrochrome, ferromanganese, and ferrosilicon.
 

Ferrous
Metals that consist primarily of iron.
 

Ferrous Alloy
(See Alloy Steel)
 

Finmet
The process reduces iron ore fines with gas in a descending series of fluidized bed reactors. The reduced iron is hot briquetted.
 

Finish
The surface appearance of steel after final treatment.
 

Finishing Facilities
The portion of the steelmaking complex that processes semi-finished steel (slabs or billets) into forms that can be used by others. Finishing operations can include rolling mills, pickle lines, tandem mills, annealing facilities, and temper mills.
 

Flat-Rolled Steel
Category of steel that includes Sheet, Strip, and Tin Plate, among others.
 

Flux
An iron cleaning agent. Limestone and lime react with impurities within the metallic pool to form a slag that floats to the top of the relatively heavier (and now more pure) liquid iron.
 

FOB (Freight On Board) Pricing
Phrase that explains whether the transportation costs of the steel are included. "FOB Mill" is the price of steel at the mill, not including shipping.
 

Freight Equalization
A common industry practice when a mill sells steel outside its geographic area; it will assume any extra shipping costs (relative to the competition) to quote the customer an equivalent price to get the business.
 

G
Galvanized Steel
Steel coated with a thin layer of zinc to provide corrosion resistance in underbody auto parts, garbage cans, storage tanks, or fencing wire. Sheet steel normally must be cold-rolled prior to the galvanizing stage.

Hot-Dipped: Steel is run through a molten zinc coating bath, followed by an air stream "wipe" that controls the thickness of the zinc finish.

Electrogal Vanized: Zinc plating process whereby the molecules on the positively charged zinc anode attach to the negatively charged sheet steel. The thickness of the zinc coating is readily controlled. By increasing the electric charge or slowing the speed of the steel through the plating area, the coating will thicken.

Differences: Electrogalvanizing equipment is more expensive to build and to operate than hot dipped, but it gives the steelmaker more precise control over the weight of the zinc coating. The automotive manufacturers, because they need the superior welding, forming and painting ability of electrogalvanized steel, purchase 90% of all tonnage produced.
 

Galvalume®
Steel sheet with a unique coating of 55% aluminum and 45% zinc that resists corrosion. The coating is applied in a continuous hot-dipped process, which improves the steel's weather resistance. Galvalume is a trademark of BHP Steel, and the product is popular in the metal building market.
 

Gathering Line
A pipeline, usually of small diameter, used to move crude oil or gas from the field to a main pipeline.
 

Gauge
The thickness of sheet steel. Better-quality steel has a consistent gauge to prevent weak spots or deformation.
 

Grades
In addition to the designations of carbon and alloy, steels are frequently specified by a grade which indicates a chemical composition.
 

Greenfield Steel Mill
New mill that is built "from scratch," presumably on a green field.

H

Hardening
Process that increases the hardness of steel, i.e., the degree to which steel will resist cutting, abrasion, penetration, bending, and stretching. The increased endurance provided by hardening makes steel suitable for additional applications.

Hardening can be achieved through various methods, including (1) heat treatment, where the properties of steel are altered by subjecting the steel to a series of temperature changes; and (2) cold working, in which changes in the structure and shape of steel are achieved through rolling, hammering, or stretching the steel at a relatively low temperature.
 

Heat (of steel)
A batch of refined steel. A basic oxygen or electric furnace full of steel. One heat of steel will be used to cast several slabs, blooms or billets.
 

Heat Treatment
Altering the properties of steel by subjecting it to a series of temperature changes.

Why: To increase the hardness, strength, or ductility of steel so that it is suitable for additional applications.

How: The steel is heated and then cooled as necessary to provide changes in the structural form that will impart the desired characteristics. The time spent at each temperature and the rates of cooling have significant impact on the effect of the treatment.
 

Heavy Structural Shapes
A general term given to rolled flanged sections that have at least one dimension of their cross sections three inches or greater. The category includes beams, channels, tees and zees if the depth dimension is three inches or greater, and angles if the length of the leg is three inches or greater.
 

High-Carbon Steel
Steel with more than 0.3% carbon. The more carbon that is dissolved in the iron, the less formable and the tougher the steel becomes. High-carbon steel's hardness makes it suitable for plow blades, shovels, bedsprings, cutting edges, or other high-wear applications.
 

Hot Band (Hot-Rolled Steel)
A coil of steel rolled on a hot-strip mill (hot-rolled steel). It can be sold in this form to customers or further processed into other finished products.
 

Hot Briquetted Iron (HBI)
Direct reduced iron that has been processed into briquettes. Instead of using a blast furnace, the oxygen is removed from the ore using natural gas and results in a substance that is 90%-92% iron. Because DRI may spontaneously combust during transportation, HBI is preferred when the metallic material must be stored or moved.
 

Hot End
The section of a steelmaking complex from the furnace up to, but not including, the hot-strip mill.
 

Hot Metal
The name for the molten iron produced in a blast furnace. It proceeds to the basic oxygen furnace in molten form or is cast as pig iron.
 

Hot-Strip Mill
A rolling mill of several stands of rolls that converts slabs into hot-rolled coils. The hot-strip mill squeezes slabs, which can range in thickness from 2-10 inches, depending on the type of continuous caster, between horizontal rolls with a progressively smaller space between them (while vertical rolls govern the width) to produce a coil of flat-rolled steel about a quarter-inch in thickness and a quarter mile in length.
 

HYL I, HYL III
Processes for producing DRI and HBI developed by Hylsa. The processes reduce iron ore lump or pellets with reformed natural gas in a vertical shaft furnace. The HYL I process uses four fixed-bed reactors; HYL III uses a single-shaft furnace.
 

Hydroforming
A forming process in which a tube is placed into a forming die. The tube is then formed to the shape of the die through the application of internal water pressure.

The hydroforming process allows for severe shape deformation, making it ideal for automotive structural parts such as engine cradles, radiator supports and body rails. Various shaped and sized holes can be punched in the tube almost anywhere during the process.
 

I
I-Beams
Structural sections on which the flanges are tapered and are typically not as long as the flanges on wide-flange beams. The flanges are thicker at the cross sections and thinner at the toes of the flanges. They are produced with depths of 3-24 inches.
 

Ingot
A form of semi-finished steel. Liquid steel is teemed (poured) into molds, where it slowly solidifies. Once the steel is solid, the mold is stripped, and the 25- to 30-ton ingots are then ready for subsequent rolling or forging.
 

Inmetco
Inmetco is a coal-based process similar to Fastmet that uses iron oxide fines and pulverized coal to produce a scrap substitute. Mill scale and flue dust, inexpensive byproducts of steelmaking, can be mixed with the iron oxide fines. Inmetco, unlike other direct reduction products, is intended to be hot charged into an EAF, with attendant energy savings.

The process includes three steps. First, iron oxide fines, pulverized coal and a binder are formed into pellets. Second, the pellets, two to three layers deep, are heated in a gas-fired rotary hearth furnace for 15-20 minutes to produce sponge iron. Subsequently, the iron must be desulfurized. The coal in the pellets provides much of the energy required in the second phase.
 

Integrated Mills
These facilities make steel by processing iron ore and other raw materials in blast furnaces. Technically, only the hot end differentiates integrated mills from mini-mills. However, the differing technological approaches to molten steel imply different scale efficiencies and, therefore, separate management styles, labor relations and product markets. Nearly all domestic integrated mills specialize in flat-rolled steel or plate.
 

Iron Carbide
One of several substitutes for high-quality, low-residual scrap for use in electric furnace steelmaking. Iron carbide producers use natural gas to reduce iron ore to iron carbide.
 

Iron Ore
Mineral containing enough iron to be a commercially viable source of the element for use in steelmaking. Except for fragments of meteorites found on Earth, iron is not a free element; instead, it is trapped in the earth's crust in its oxidized form.
 



L
Ladle Metallurgy Furnace (LMF)
An intermediate steel processing unit that further refines the chemistry and temperature of molten steel while it is still in the ladle. The ladle metallurgy step comes after the steel is melted and refined in the electric arc or basic oxygen furnace, but before the steel is sent to the continuous caster.
 

Leveling Line
A process to flatten any shape deficiencies (wavy edges and buckles) in the sheet, prior to final shipment. Most cold-rolled sheet initially has a crowned cross-section that, if such a shape is undesirable to the customer, must be flattened in the leveling line.
 

Light-Gauge Steel
Very thin steel sheet that has been temper-rolled or passed through a cold-reduction mill. Light gauge steel normally is plated with tin or chrome for use in food containers.
 

Line Pipe
Pipe used in the surface transmission of oil, natural gas and other fluids.
 

Long Products
Classification of steel products that includes bar, rod and structural products, that are "long", rather than "flat".
 

Low-Carbon Steel
Steel with less than 0.005% carbon is more ductile (malleable): It is capable of being drawn out or rolled thin for use in automotive body applications. Carbon is removed from the steel bath through vacuum degassing.
 

M
M sections (Bantam BeamsTM , Junior BeamsTM)
Light footweight beams primarily used in the construction of pre-engineered housing. These beams are produced in lighter footweights, usually six to 10 pounds per foot, than traditional structural products.
 

Man-Hours Per Ton
This is a measure of labor efficiency. The ratio of total hours worked by steel employees to the tons shipped for a given period of time. Changes in the inventory level and work that is contracted out will affect the reported measurement.
 

Merchant Bar
A group of commodity steel shapes that consist of rounds, squares, flats, strips, angles, and channels, which fabricators, steel service centers and manufacturers cut, bend and shape into products. Merchant products require more specialized processing than reinforcing bar.
 

Mini-Mills
Normally defined as steel mills that melt scrap metal to produce commodity products. Although the mini-mills are subject to the same steel processing requirements after the caster as the integrated steel companies, they differ greatly in regard to their minimum efficient size, labor relations, product markets, and management style.
 

N
No. 1 Heavy Melt
Obsolete steel scrap grade, at least one-quarter inch in thickness and in sections no larger than five feet by two feet. Much of the metal comes from demolished buildings, truck frames and heavy duty springs. Mini-mills are primary consumers of No. 1 heavy scrap.
 

Normalizing
Consists of heating above the upper critical temperature followed by cooling in air. Compatible hardness or tensile properties can be specified.
 

O
Oil Country Tubular Goods (OCTG)
Label applied to the pipe products used by petroleum exploration customers. OCTG includes casing, drill pipe and oil well tubing, which, depending on their use, may be formed through welded or seamless processes.
 

Open Hearth Furnace
A broad, shallow hearth to refine pig iron and scrap into steel. Heat is supplied from a large, luminous flame over the surface, and the refining takes seven to nine hours. Open Hearths, at one time the most abundant steelmaking furnaces among integrated companies, have been replaced by the basic oxygen furnace.
 

Operating Rates
The ratio of raw steel production to the mill's stated capacity. Each December, steel companies report to the AISI their estimated capacity (if they could sell all steel they produced) for the following year, adjusted for any facility downtime.
 

Order Rate
The ratio of new orders recorded to the mill's capacity to produce the steel to fill the orders. Many analysts view trends in the order rate as harbingers of future production levels.
 

Oscillating
A method of winding narrow strip steel over a much wider roll. Customers want to have as much steel on a coil as will fit in their machines, so they can spend less time moving the material and more time using it. By coiling the strip like fishing line (or thread) over a spool, a much longer strip can fit onto a coil of proper diameter. Oscillate-wound coils allow the customer to enjoy longer processing runs.
 

P
Pellets
(See Agglomerating Processes)
 

Pickling
Process that cleans a steel coil of its rust, dirt and oil so that further work can be done to the metal.

Why: When hot-rolled coils cool, rust forms on the unprotected metal; often coils are stored or transported while exposed to outside air and water.

How: Through a continuous process, the steel is uncoiled and sent through a series of hydrochloric acid baths that remove the oxides (rust). The steel sheet is then rinsed and dried.
 

Pig Iron
The name for the melted iron produced in a blast furnace, containing a large quantity of carbon (above 1.5%). Named long ago when molten iron was poured through a trench in the ground to flow into shallow earthen holes, the arrangement looked like newborn pigs suckling. The central channel became known as the "sow," and the molds were "pigs."
 

Piling (Sheet Piling)
A structural steel product with edges designed to interlock; used in the construction of cofferdams or riverbank reinforcement.
 

Pipe
Technically a tube used to transport fluids or gases. However, pipe and tube are often used interchangeably in steel lexicon, with a given label applied primarily as a matter of historical use.
 

Plate
Sheet steel with a width of more than eight inches, with a thickness ranging from one quarter of an inch to more than one foot (see Sheet Steel).
 

Powder Metals
Fabrication technology in which fine metallic powder is compacted under high pressure and then heated at a temperature slightly below the melting point to solidify the material. Primary users of powder metal parts are auto, electronics and aerospace industries.
 

Production Casing
The last string of casing set in a well, inside of which is usually suspended a tubing string.
 

Production Tubing
Tubing of smaller diameter through which oil or gas flows to the surface.
 

Pulverized Coal Injection System (PCI)
A blast furnace enhancement to reduce an integrated mill's reliance on coke (because of environmental problems with its production). Up to 30% of the coke charged into the blast furnace can be replaced by this talcum-like coal powder, which is injected through nozzles at the bottom of the furnace.
 

Q
Q-BOP
Modified Basic Oxygen Furnace in which the oxygen and other gases are blown in from the bottom, rather than from the   . While the Q-BOP stirs the metal bath more vigorously, allowing for faster processing, the design produces essentially the same steel grades as the top-blowing basic oxygen furnace. Today's state-of-the-art furnace design combines the previous technologies: 60% of the oxygen is blown from above, with the rest blown through the bottom of the vessel.
 

Qualification Trials
The testing required for a new process adopted to make certain grades of steel with exacting end uses. In order for the process to become qualified, the steel made by the process must be tested.
  

R
Reducing Agent
Either natural gas or coal can be used to remove the oxygen from iron ore in order to produce a scrap substitute. In gas-based processes, the iron ore is heated in a vessel as reformed natural gas passes through. In coal-based processes, iron ore is combined with gasified or ground coal and heated. The oxygen in the ore combines with carbon and hydrogen in the gas or coal, producing reduced, or metallic, iron.
 

Refractory Brick
Heat-resistant brick. Because its melting point is well above the operating temperatures of the process, refractory bricks line most steelmaking vessels that come in contact with molten metal, like the walls of the blast furnace, sides of the ladles, and inside of the BOF.
 

Reinforcing Bar (Rebar)
A commodity-grade steel used to strengthen concrete in highway and building construction.
 

Reline
The process of replacing the refractory lining of a liquid steel vessel. Once it wears out, the brick lining of a furnace must be cooled, stripped and replaced. 
 


Residuals
The impurities in mini-mill steel as the result of the mix of metals entering the process dissolved in obsolete scrap. Residuals are key concerns regarding the mini-mills' recent entry into the flat-rolled market, where high residuals can leave sheet steel too brittle for customer use.
 

Reversing Mill
The stand of rolls used to reduce steel sheet or plate by passing the steel back and forth between the rolls; the gap between the rolls is reduced after each pass.
 

Rig
The derrick or mast, draw-works, and attendant surface equipment of a drilling or work-over unit.
 

Rod
Round, thin semi-finished steel length that is rolled from a billet and coiled for further processing. Rod is commonly drawn into wire products or used to make bolts and nails. Rod trains (rolling facilities) can run as fast as 20,000 feet per minute; more than 200 miles an hour.
 

Roll Force Systems
Mill stands place considerable pressure on slabs, blooms and coils to further process the material. There are two general ways of applying the force to the steel; screw and hydraulic systems.

Screw (Incline Plane) This older method used the basic principle of the screw to adjust the space between the mill rolls. Because metal touches metal, these configurations will wear down over time and can cause quality problems.

Hydraulic (Pancake Cylinder) This modern system uses fluid pressure to rapidly adjust the roll spacing several times per second. These minute, instantaneous adjustments allow for superior gauge tracking and higher-quality products.
 

S
Scale
The oxide of iron that forms on the surface of steel after heating.
 

Scrap (Ferrous)
Ferrous (iron-containing) material that generally is remelted and recast into new steel. Integrated steel mills use scrap for up to 25% of their basic oxygen furnace charge; 100% of the mini-mills' raw material for their electric furnaces generally is scrap.

Home Scrap: Waste steel that is generated from within the steel mill, through edge trimming and rejects. It normally is sent directly back to the furnace.

Prompt (Industrial) Scrap: Excess steel that is trimmed by the auto and appliance stampers and auctioned to scrap buyers as factory bundles. This is a high-quality scrap as the result of its low-residual content and consistent chemistry.

Obsolete Scrap: Iron-bearing trash. Automobile hulks, worn-out refrigerators and useless storage tanks, for example, can be recovered from the junkyard and remelted. The residual impurity of such scrap normally relegates obsolete scrap to the mini-mills (see No. 1 Heavy Melt).
 

Scrap Substitute
Raw material that can be charged in place of scrap in electric arc furnaces and basic oxygen furnaces. Scrap substitutes include, among others, DRI, HBI, iron carbide, and pig iron.
 

Seamless Pipe
Pipe made from a solid billet, which is heated, then rotated under extreme pressure. This rotational pressure creates an opening in the center of the billet, which is then shaped by a mandrel to form pipe.
 

Secondary Steel
Steel that does not meet the original customer's specifications because of a defect in its chemistry, gauge or surface quality. Mills must search to find another customer (that can accept the lower quality) to take the off-spec steel at a discount. While secondary will not affect the reported yield, margins will suffer.
 

Semi-finished Steel
Steel shapes—for example, blooms, billets or slabs—that later are rolled into finished products such as beams, bars or sheet.
 

Shape Correcting
Rolling, heating and quenching steel sheets often affect the dimensions of the steel. Levelers, temper mills and edge trimmers rework the processed steel to match customer specifications.
 

Shearing
If the edges of sheet and strip are not controlled during reduction, they must be trimmed parallel by shears. This process may be performed by either the steel mill or steel processor to match customer needs.
 

Sheet Steel
Thin, flat-rolled steel. Coiled sheet steel accounts for nearly one-half of all steel shipped domestically and is created in a hot-strip mill by rolling a cast slab flat while maintaining the side dimensions. The malleable steel lengthens to several hundred feet as it is squeezed by the rolling mill. The most common differences among steel bars, strip, plate, and sheet are merely their physical dimensions of width and gauge (thickness).
 

Shredded Scrap
Fist-sized, homogenous pieces of old automobile hulks. After cars are sent through a shredder, the recyclable steel is separated by magnets. Mini-mills consume shredded scrap in their electric arc furnace operations.
 

Silicon Electrical Steel
A type of specialty steel created by introducing silicon during the steelmaking process. Electrical steel exhibits certain magnetic properties, which make it optimum for use in transformers, power generators and electric motors.

Grain-Oriented: The metal's grain runs parallel within the steel, permitting easy magnetization along the length of the steel. Although grain-oriented steel may be twice as expensive to produce, its magnetic directional characteristics enable power transformers, made from this metal, to absorb less energy during operation.

Non-Gran-Oriented: Because there is no preferential direction for magnetization, non-grain-oriented steel is best used in rotating apparatus such as electric motors.
 

Sintering
A process that combines iron-bearing particles, once recovered from environmental control filters, into small pellets. Previously, these materials were too fine to withstand the air currents of the smelting process and were thrown away. The iron is now conserved because the chunks can be charged into the blast furnace (see Agglomerating Processes).
 

Skelp
Steel that is the entry material to a pipe mill. It resembles hot-rolled strip, but its properties allow for the severe forming and welding operations required for pipe production.
 

Slab
The most common type of semi-finished steel. Traditional slabs measure 10 inches thick and 30-85 inches wide (and average about 20 feet long), while the output of the recently developed "thin slab" casters is approximately two inches thick. Subsequent to casting, slabs are sent to the hot-strip mill to be rolled into coiled sheet and plate products.
 

Slag
The impurities in a molten pool of iron. Flux such as limestone may be added to foster the congregation of undesired elements into a slag. Because slag is lighter than iron, it will float on top of the pool, where it can be skimmed.
 

Slitting
Cutting a sheet of steel into narrower strips to match customer needs. Because steel mills have limited flexibility as to the widths of the sheet that they produce, service centers normally will cut the sheet for the customer.
 

Special Bar Quality (SBQ)
SBQ represents a wide variety of higher-quality carbon and alloy bars that are used in the forging, machining and cold-drawing industries for the production of automotive parts, hand tools, electric motor shafts and valves. SBQ generally contains more alloys than merchant quality and commodity grades of steel bars, and is produced with more precise dimensions and chemistry.

Specialty Steel
Category of steel that includes electrical (see Silicon Electrical Steel), alloy (see Alloy Steel), stainless (see Stainless Steel) and tool (see Tool Steels) steels.
 

Specialty Tube
Refers to a wide variety of high-quality custom-made tubular products requiring critical tolerances, precise dimensional control and special metallurgical properties. Specialty tubing is used in the manufacture of automotive, construction and agricultural equipment, and in industrial applications such as hydraulic cylinders, machine parts and printing rollers. Because of the range of industrial applications, the market typically follows general economic conditions.
 

Spot Market
Sales for delivery in less than three months.
 

Stainless Steel
The term for grades of steel that contain more than 10% chromium, with or without other alloying elements. 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.
 

Statistical Process Control(SPC)
A technique used to predict when a steelmaking function's quality may deteriorate. By tightly monitoring the product's variance from specifications, the operator can determine when to apply preventative maintenance to a machine before any low-quality (secondary) steel is produced.
 

Steckel Mill
A reversing steel sheet reduction mill with heated coil boxes at each end. Steel sheet or plate is sent through the rolls of the reversing mill and coiled at the end of the mill, reheated in the coil box, and sent back through the Steckel stands and recoiled. By reheating the steel prior to each pass, the rolls can squeeze the steel thinner per pass and impart a better surface finish.
 

Steel Intensity
The amount of steel used per unit of gross domestic product. Intensity reflects the secular demand for steel, as opposed to cyclical demand. The amount of steel used in vehicles and the popularity of alternative materials affect the intensity, or how much steel is needed per unit produced. The state of the economy, however, determines the number of units.
 

Steel-Intensive Products
Consumer products such as automobiles and appliances that, because so much of their weight is from steel, exhibit a high demand correlation with steel.
 

Steel Strapping
Banding and packaging material that is used to close and reinforce shipping units, such as bales, boxes, cartons, coils, crates, and skids.
 

Strength
Properties related to the ability of steel to oppose applied forces. Forms of strength include withstanding imposed loads without a permanent change in shape or structure and resistance to stretching.
 

Strip
Thin, flat steel that resembles hot-rolled sheet, but it is normally narrower (up to 12 inches wide) and produced to more closely controlled thicknesses. Strip also may be cut from steel sheet by a slitting machine (see Sheet Steel).
 

Structurals
Steel product group that includes I-beams, H-beams, wide-flange beams and sheet piling. These products are used in the construction of multi-story buildings, industrial buildings, bridge trusses, vertical highway supports, and riverbank reinforcement.
 

Substrate
Raw material used as an input for steel processing: For example, hot-rolled steel is the substrate for cold-rolling operations.
 

Surface Casing
The first string of casing that is set in a well.
 

T
Taconite
Natural mineral containing less than 30% iron. It is the primary ore used in blast furnaces. Domestic supplies of iron-rich ores (greater than 50% iron) were largely depleted in the 1940s, so integrated steel companies now process the lower-grade taconite to make it useful.
 

Tailored Blanks
A section of sheet or strip that is cut-to-length and trimmed to match specifications for the manufacturer's stamping design for a particular part. Because excess steel is cut away (to save shipping costs), all that remains for the stamper is to impart the three-dimensional shape with a die press (see Blanking).
 

Tandem Mill
A type of cold-rolling mill, the tandem mill imparts greater strength, a uniform and smoother surface, and reduced thickness to the steel sheet. Unlike the original single-stand mills, a tandem mill rolls steel through a series of rolls (generally three to five in a row) to achieve a desired thickness and surface quality.
 

Teeming
Pouring; ingot molds are filled (teemed) by iron-bearing ladles.
 

Temper Mill
A type of cold-rolling mill, usually with only one or two stands, that finishes cold-rolled, annealed sheet steel by improving the finish or texture to develop the required final mechanical properties. By changing the rolls of the temper mill, steel can be shipped with a shiny, dull or grooved surface.
 

Terne
Sheet steel coated with a mixture of lead and tin. Terne principally is used in the manufacture of gasoline tanks, although it also can be found in chemical containers, oil filters and television chassis.
 

Thread
A continuous spiral rib, as on a screw or pipe.
 

Threaded Coupling
A type of connector that has threads on each end, making it possible to screw two pieces of pipe together.
 

Thread Protector
A metal or plastic device that is screwed onto or into pipe threads to protect them from damage when the pipe is not in use.
 

Tin Mill
Continuous tin-plating facility to produce tin mill steel sheet to be used in food and beverage cans and other containers.
 

Tin/Chrome Plating
A plating process whereby the molecules from the positively charged tin or chromium anode attach to the negatively charged sheet steel. The thickness of the coating is readily controlled through regulation of the voltage and speed of the sheet through the plating area.
 

Tin-Free Steel
Chromium-coated steel. Because it is used in food cans just like tin plate, it ironically is classified as a tin mill product.
 

Tin Plate
Thin sheet steel with a very thin coating of metallic tin. Tin plate is used primarily in canmaking.
 

Tolerances
A customer's specifications can refer to dimensions or to the chemical properties of steel ordered. The tolerance measures the allowable difference in product specifications between what a customer orders and what the steel company delivers. There is no standard tolerance because each customer maintains its own variance objective. Tolerances are given as the specification, plus or minus an error factor; the smaller the range, the higher the cost.
 

Toll Processing
The act of processing steel for a fee ("toll"). Owners of the steel sheet may not possess the facilities to perform needed operations on the material (or may not have the open capacity). Therefore, another steel mill or service center will slit, roll, coat, anneal, or plate the metal for a fee.
 

Tool Steels
Steels that are hardened for the use in the manufacture of tools and dies.
 

Ton
Unit of measure for steel scrap and iron ore.
Gross Ton - 2,240 pounds.
Long (Net) Ton - 2,240 pounds.
Short (Net) Ton - 2,000 pounds. Normal unit of statistical raw material input and steel output in the United States.
Metric Ton - 1,000 kilograms. 2,204.6 pounds or 1.102 short tons.
 

Trade Case
A type of lawsuit filed by United States companies against their foreign counterparts in response to imports at prices lower than those in the U.S. market. Sanctions can be imposed by the International Trade Commission and the Commerce Department on foreign producers involved in dumping and government subsidization, if domestic manufacturers can prove material damage to their results.
 

Transmission Line
A pipeline used to transmit natural gas or other fluids.
 

Tubing
When referring to OCTG, tubing is a separate pipe used within the casing to conduct the oil or gas to the surface. Depending on conditions and well life, tubing may have to be replaced during the operational life of a well.
 

Tundish
The shallow refractory-lined basin on top of the continuous caster. It receives the liquid steel from the ladle, prior to the cast, allowing the operator to precisely regulate the flow of metal into the mold.
 

Tunnel Furnace
Type of furnace whereby stock to be heated is placed upon cars which are then pushed or pulled slowly through the furnace.
 

V
Vacuum Degassing
An advanced steel refining facility that removes oxygen, hydrogen and nitrogen under low pressures (in a vacuum) to produce ultra-low-carbon steel for demanding electrical and automotive applications. Normally performed in the ladle, the removal of dissolved gases results in cleaner, higher-quality, more pure steel (see Ladle Metallurgy Furnace).
 

W
Walking Beam Furnace
A type of continuous reheat furnace in which the billet or slab moves through distinct heating zones within the furnace: By controlling the speed through the zones, steelmakers can achieve precise rolling temperatures and consume less fuel during operation.
 

Wide-Flange Beam
A structural steel section on which the flanges are not tapered, but have equal thickness from the tip to the web and are at right angles to the web. Wide-flange beams are differentiated by the width of the web, which can range from 3 inches to more than 40 inches, and by the weight of the beam, measured in pounds per foot.
 

Widths
The lateral dimension of rolled steel, as opposed to the length or the gauge (thickness). If width of the steel strip is not controlled during rolling, the edges must be trimmed.
 

Y
Yield
The ratio of the quantity of finished shipments to the total raw steel produced, adjusted for changes in inventory and any slabs that are purchased from outside.



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یکشنبه 26 دی 1395 07:58 ب.ظ
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