Salamander
When a blast furnace has been in operation for an extended period of time, the portion near the center of the hearth that cannot be cooled adequately gradually erodes away, leaving a dish-shaped cavity in the hearth blocks that may be as much as 2 to 3 metres deep. This cavity fills with liquid metal which remains in the furnace hearh during tapping because its elevatyion is well below that of the iron notch. This metal is known as salamander (or ‘bear’). The hot metal accumulated therein is drained-out immediately after the last cast, to prevent solidification of 400-600 tonnes of hot metal into a huge chunk that would have to be blasted-out during relining.

Salt Spray Test
A test to determine the life of coated steel when exposed to corrosive saltwater solution (generally 5% NaCl).

Saturated Gas
A gas which contains the maximum amount of water vapour it can hold without any condensation of water taking place.

Sand Marksb
Patches of furnace refractory material embedded on the surface of hot steel and rolled subsequently.

Scab
Irregular shaped patches of metal on ingot surface arising from cavities in mould walls or caused by loosely adhering layers of metal.

Scaffolding
The term used when accretions or scabs build up on the blast furnace walls and cause a decrease in the cross-sectional area of the furnace stack.

Scale Breaking
Breaking up of scale layer on slabs, blooms or billets during rolling by the application of water jets under pressure. Breaking the scale by repeated reverse bends by passing the hot steel through a suitable machine, a procedure which helps to minimise the kinks during subsequent processing, is also practised.

Scarfing (Deseaming)
1. Cutting the surface of slabs, ordinarily by using a gas torch, to remove surface defects prior to rolling at the Hot Mill.
2. Making a chamfered end for hammer welding two bars together.

Scleroscope Hardness Test
A dynamic indentation hardness test using a calibrated instrument that drops a diamond-tipped hammer from a fixed height onto the surface of the material being tested. The height of rebound of the hammer is a measure of the hardness of the material.

Scoring
In tribology, a severe form of wear characterized by the formation of extensive grooves and scratches in the direction of sliding.

Scrap (Ferrous)
Ferrous (iron-containing) material that generally is re-melted 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 (Revert) Scrap Waste steel that is generated from within the steel mill, through edge trimming, rejects and metallic losses in slag. 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 (Reclaimed) Scrap Iron-bearing trash. Automobile hulks, worn-out refrigerators and useless storage tanks, for example, can be recovered from the junkyard and re-melted. The residual impurity of such scrap normally relegates obsolete scrap to the mini-mills (see No. 1 Heavy Melt).

Scraped Edge
An edge with abrasion markings due to incorrect setting of guides.

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.

Scratch or Gouge
This type of defect can be recognized, in most cases, as to its source. If the scratch or gouge occurs in the hot strip mill there will be an oxide which has formed at the base of it. Scratches or gouges occurring at the finishing end can be recognized by the bright appearance at the base of the defect which is indicative of oxide removal after the steel has cooled.

Scratching
In tribology, the mechanical removal or displacement, or both, of material from a surface by the action of abrasive particles or protuberances sliding across the surface. See also plowing.

Screw Down Mechanism
Used on mills to position the top roll for each pass through the mill, except on continuous and three-high mills where fixed passes are used. The top roll is adjusted by screws which extend through the top of each housing.

Screw Stock
Free cutting steel bars suitable for the manufacture of bolts and screws.

Scuffling
A form of adhesive wear that produces superficial scratches or a high polish on the rubbing surfaces. It is observed most often in inadequately lubricated parts.

Seam
Long, shallow grooves or striations formed during working by the elongation of oxidised surface or subsurface blow-holes. Seams may also be caused by rippled surfaces or by recurrent teeming laps.

Seamless Pipe
A pipe without a longitudinal joint or weld, 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 Cooling
During slab casting operation, the secondary cooling system starts from the bottom of the mould through complete solidification of the strand to the cut-off operations. The system, conventionally, consists of water sprays which are directed at the strand surface through openings between the containment rolls. Recently, air-water mist sprays have been employed which provide more uniform cooling.

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.

Secondary Steel Making
The purpose of secondary steel making (also referred to as ladle metallurgy) is to produce ‘clean’ steel, steel which satisfies stringent requirements of surface, internal and micro-cleanliness quality and of mechanical properties. Ladle metallurgy is a secondary step of the steel making process often performed in a ladle after the initial refining process in a primary furnace is completed.

Section
A hot rolled product widely used for structural purposes, with a cross-section of special contour. The common types are equal & unequal angles, bulb plate & angle, channel, round, square, flat, beam, tee bar, zed bar etc.

Section Tubes
Tube with a cross section other than circular.

Seediness
Coating defects consisting of the randomly spaced undissolved particles, usually resin particles, which are immersed in the coating. They are raised up in the coating and appear somewhat like fine sand sprinkled throughout the film.

Segregation
A non-uniform distribution of some constituents and / or impurities in a cast product characterised by the mode of solidification of alloys. Segregation usually persists through subsequent hot and cold working. Generally the concentration of low melting constituents tends to be higher in the centre than the surface. Sometimes, the reverse of this phenomenon takes place and is known as inverse segregation.

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

Sendzimir Mill (Z-mill)
What Compact mill used for rolling cold coils of stainless steel in order to make the steel thinner, smoother, and stronger.
Why To control the thickness of steel better at lower capital cost, and to roll thinner sheets and strips.
How Stainless steel sheet or strip passes between a matching pair of small work rolls with extremely smooth surfaces, heavily reinforced by clusters of back-up rolls. The rolls reduce the steel to the desired thickness.

Sequence Casting
Casting machine set-up, after the completion of a cast, is time consuming since it involves feeding the dummy bar through the entire length of the casting machine into the mould cavity and packing the dummy bar head to prevent leakage between the mould wall and head. Sequence casting was developed to reduce the frequency of setting the dummy bar by casting a series of heats in succession without interrupting the casting process.

Service Center
A catchall name for an operation that buys steel, often processes it in some way and then sells it in a slightly different form. A service center is distinguished from an end-user by the fact that, unlike an end-user, a service center sells steel, not a fabricated product. Service centers are manufacturers to the extent that they add labor to steel by providing a service.

Shafting (Lathe Turned)
Bright material usually produced by lathe turning, polishing and hand setting to given limits of dimensions and straightness.

Shape Control
Ability to produce material to a given geometric flatness standard. (See Flatness)

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.

Shape Defect
Geometric non-uniformity of a strip, such as bent strip, coil set, center buckle, wavy edge, etc.

Sheared Edges
Edges detached by shearing (and at times by slitting wheel).

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.

Shear Distortion
A mashed or deformed end on a bar caused by defective or improperly adjusted shearing equipment.

Sheet
A hot or cold-rolled flat product, rolled in rectangular sections of thickness below 5 mm and supplied in straight lengths. The width is at least 100 times the thickness and the edges can be mill trimmed, sheared or flame cut. A sheet can also be obtained by cutting of strips.

Sheet Bar (Slab Bar)
Semi-finished product of rectangular section, of thickness not less than 6mm and width not less than 150mm, and of such dimensions that the thickness does not exceed one-fourth of the width. This term also includes tin plate bars.

Sheet Products
1. Hot Rolled : Uncoated, heavy gauge, fully processed in Strip Steel, never cold reduced at Tandem Mill.
2. Cold Rolled : Uncoated, heavy gauge, primarily processed in Strip Steel, although some goes to the Tin Mill, always cold reduced at Tandem Mill.
3. Galvanized : "Bath" coated with zinc, heavy gauge, primarily processed through Strip Steel & Sheet Mill, majority is cold reduced at Tandem Mill.
4. Electro-galvanized : Zinc coated, normally lighter gauge than galvanized, processed through Strip Steel & Tin Mill, mostly single reduced. (Tandem)

Sheet Slab
A slab of suitable size for rolling into sheet.

Sheet Steel
Thin, flat-rolled steel. Coiled sheet 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).

Product Classification by Size

Specified Thickness in Inches Specified Width in Inches
Up to 6 Over 6 to 8 Over 8 to 12 Over 12 to 48 Over 48
0.2300 + Bar Bar Plate Plate Plate
0.2299 - 0.2040 Bar Bar Plate Plate Plate
0.2039 - 0.1800 Strip Strip Strip Sheet Plate
0.1799 - 0.0449 Strip Strip Strip SheetSheet

Shell (Scab, Sliver, Spill)
A relatively thin film or torque of metal imperfectly attached to the surface of steel. The defect on the sides of the ingot caused by metal splashes during teeming, having solidified and stuck to the mould wall is also called shell or splash.

Short (Cut Bar)
The portion left out after specified lengths are cut out or sheared from a long length in hot-rolled product.

Shortness
A form of brittleness in metal. It is designated a ‘cold’, ‘hot’, and ‘red’ to indicate the temperature range in which the brittleness occurs.

Shot Blast Roll Finish
The surface finish (with a grit micro-finish) on the rolls in the last stand of tandem mill or temper mill; determines the surface finish of the product where a grit finish produced to a specified micro-inch reading is desired.

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.

Siderite
Chemical composition FeCO3, corresponding to 48.20% of iron, 37.99% of CO2 and 13.81% of oxygen; specific gravity 3.83 to 3.88. The siderite ores are sometimes termed ‘spathic iron ore’ or ‘black-band ore’. Carbonate ores are commonly calcined before they are charged into the blast furnace. They frequently contain enough lime and magnesite to be self-fluxing.

Side Trimming
Removing continuously the desired amount from both edges of the strip, thereby establishing accurate and uniform width and producing parallel and reasonably smooth edges. These trimmers employ mating circular knives which are mounted on arbors.

Silica
Silicon dioxide (SiO2) occurring in nature as sand and ganister, with varying amounts of other impurities. It is used as an acid refractory.

Silicate
A compound of silica and a metallic oxide.

Silicon Electrical Steel
A type of specialty steel created by introducing silicon during the steel-making process. Electrical steel exhibits certain magnetic properties (such as greatly increased electrical resistivity, high permeability and greatly reduced core losses), which make it optimum for use in transformers, power generators and electric motors. They are of two types :
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-Grain-Oriented Because there is no preferential direction for magnetization, non-grain-oriented steel is best used in rotating apparatus such as electric motors.

Silky Fracture
A metal fracture in which the broken metal surface has a fine texture, usually dull in appearance. Characteristic of tough and strong metals.

Single Reduced
Refers to temper rolling in the tin mill. No gauge reduction occurs here. Steel sheet that is rolled in multiple-strand reduction mills while cold, then annealed and temper rolled to produce thin gauges for can making. Besides reducing gauge and permitting fabrication of lighter weight cans, cold rolling also improves the steel’s surface and metallurgical properties.

Single Shear Steel (Faggot)
A cutlery steel obtained by forging (and welding) a pile of converted bars (teemed as a faggot). At times, the forged product is piled by cutting it into pieces and reforged, the resulting product being termed as a double-shear steel.

Single Spot Test
A test of galvanized (or any other metallic) coating weights administered by sampling the coated steel across the width at two inches from each edge and dead center. See Triple Spot Test.

Sinter
One form of agglomeration of fines (iron ore fines, coke, flue dust, mill scale, limestone and dolomite fines) roasted into lumps by heating at lower temperature till clinker like aggregate is formed which is well-suited for use as a blast furnace feed.

Sinter Coolers
Rotary-type and shaft-type coolers used in conjunction with a water quench. The most recent developments in sinter cooling have been directed towards on-strand cooling. This improves heat recuperation, sinter quality, and dust collection.

Sinter Cooling
Cooling of the sinter below 150o so that it can be handled on conveyor belts.

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.

Skid Marks
Visibly colder "stripes" on slabs caused by contact with water-cooled skids in a pusher-type reheat furnace. Walking beam reheat furnaces eliminate skid marks.
Skimmer Block
A refractory block in the blast furnace cast house which holds back the slag and diverts it into the slag runners.

Skin Holes
Holes visible on ingot surface.

Skin Passing (Killing / Pinch Passing)
Passing hot-rolled, annealed or normalized sheets in cold state through rolls for removing kinks, stretcher strains or similar surface conditions, develop mechanical properties, and/or reduce the tendency of stretcher strain or fluting during forming. the cold deformation being very light. Usually reduction is less than 5 percent.

Skin Roll
A product that has been processed at the Skin Mill.

Skull
Solidified metal with some amount of slag and refractories remaining in furnace or ladle after the molten metal is poured out. It may also refer to the film formed inside a mould after casting. If detached, it may get entrapped and lead to skull patches.

Skull Patch
Thin layer of solid metal deposited in the inner mould wall and trapped during teeming.

Slab
The most common type of semi-finished steel - rolled, forged or continuously cast. The thickness does not exceed one third of the width. 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.

Slab Slitting
Rather than interrupting a string of heats to change the mould size, a practice has evolved in which a small number of master slab sizes are cast with the slab product being slit longitudinally in a separate operation using mechanized oxy-natural gas torches.

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. Slags act as a carrier of oxygen to the molten bath for the oxidation and removal of various elements (such as carbon, silicon, phosphorus, etc.) from the molten charge. Usually slags consist of combinations of acid oxides with basic oxides and neutral oxides are added to aid fusibility. Because slag is lighter than iron, it will float on top of the pool where it can be skimmed.

Slagging
Taking out molten slag from the furnace.

Slag Foaming
Whenever gas passes through a liquid, the liquid expands due to the presence of the gas. During steel-making, oxygen lancing causes formation of stable slag foam bubbles on top of the molten hot metal. While some foam is desirable to help capture the energy from post combustion, excessive foaming can lead to slopping in oxygen steel-making. On the other hand, controlled foaming in the electric arc furnace is desirable to protect the refractories from the electric arc radiation.

Slag Patch (Slag Inclusion)
Slag trapped in the steel during solidification.
Slag Pots (Slag Ladles, Cinder Pots, Slag Pans)
Cast or fabricated receptacles used for slag disposal.

Slag Notch
3 to 5 feet above the iron notch level is the cinder notch or slag notch. This originally was used to withdraw slag from the blast furnace between iron casts. Formerly, before burdens were beneficiated, slag volumes were quite large and it was a great advantage to remove slag, which is lighter than iron and floats on top of it, before casting to decrease the undesirable high liquid level in the hearth and to avoid having to remove a large volume of slag through the tapping hole. Because liquid slag does not dissolve copper as liquid iron does, the slag is now withdrawn through a water-cooled copper member called a monkey.

Slag Splashing and Coating
Slag splashing (and coating) is a technology which uses high pressure nitrogen through the oxygen lance after tapping the heat to coat the refractory lining on the walls and cone of the converter with remaining slag. The slag coating thus formed cools and solidifies on the existing refractory, and serves a the consumable refractory coating in the next heat. Slag splashing requires only a minute or two to perform and is done when the vessel is in vertical position after the heat is tapped. The process has greatly reduced the need for gunning of the lining by more than half and has contributed substantially to maintaining furnace lining profiles for safety and performance. Slag coating is an art form that requires considerable attention if it is to be done most effectively. Actions that make coating practices successful include : selecting the right slag, making the right and proper amount of additions, rocking the vessels correctly, disposing of the slag when necessary, and coating when it is the best time.

Sliding Gate
Flow of liquid steel from the ladle to the mould may be controlled by stopper rods or sliding gates. More recently, more ladles have been equipped with a sliding gate system when the extended holding times or other factors associated with continuous casting or in ladle processing have required external flow-control systems.

Slips
Caused initially by hanging or bridging of the burden material in the stack of the furnace. When this occurs, the material below the ‘hang’ continues to move downward, forming a space that is void of solid material but filled with hot gas at very high pressure. This space continues to grow until the hang finally collapses. In severe cases, the sudden downward thrust of the hanging material (called ‘slip’) forces the hot gas upward with the force of an explosion. This sudden rush of gas opens the explosion bleeders and sometimes is so great that is causes severe damage to the furnace-top gear.

Slit Edge
The relatively smooth edge produced from side trimming or slitting. See Mill Edge.

Slitter
1. Area on the Pickler where the strip is side-trimmed (slit) to its proper width. 2. Side-trims the edges of the strip to certain width in the customer’s specifications, or the vertical cutting of coil material to form narrow strip product.

Slitting
Cutting a sheet of steel into a number of narrower strips by means of rotary cutters, 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.

Slivers
Slivers are due to defective teeming of the molten metal and to a tearing of corners of the steel in blooming, roughing, or finishing. Tearing is attributed to many things, such as over-oxidation in the open hearth, or burning during re-heating or soaking.

Snarl
A link which has been drawn tight in a wire.

Snowflakes
When hairline cracks are exposed by fracturing, they appear as bright crystalline areas of almost circular form, sometimes known as snowflakes.

Soaking
Holding the material in a furnace after the outside has reached the desired temperature until uniformity of that temperature has been reached throughout its mass and any desired metallurgical changes have been completed.

Soldering
Joining metals by fusion of alloys that have relatively low melting points – most commonly, lead-base or tin-base alloys, which are the soft solders. Hard solders are alloys that have silver, copper, or nickel bases and use of these alloys with melting points higher than 800o F is generally termed brazing.

Spalling
The cracking and flaking of metal particles out of a surface.

Spangle
Finish achieved when zinc is allowed to "freeze" naturally on the sheet during galvanizing. Achieved by adding antimony to the hot dip bath.

Spangle Free
A galvanized product in which the spangle formation has been suppressed; accomplished by eliminating antimony and lead in the molten zinc bath during the production of Hot Dipped Galvanized. Galvannealed is always spangle free.

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.

Special Killed
1. Low carbon aluminum killed steels used mainly for extra deep drawing varieties of sheet and strip. 2. Steel deoxidized by silicon or aluminum or in combination to reduce the oxygen content to a minimum so that no reaction occurs during solidification of the metal.

Special Steel
Steel in the production of which special care has to be taken so as to attain the desired cleanliness, surface quality and mechanical properties.

Special Treatment
A treatment applied to electro-galvanized product to enhance corrosion resistance.

Specialty Steel
Category of steel that includes electrical (see Silicon Electrical Steel), alloy (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.

Specifications
The chemical composition and dimensions of products made by the plant. The specifications include all processes required to achieve the finished product.

Spheroidization Annealing
It is a type of annealing which causes practical all carbides in the steel to agglomerate in the form of small globules or spheroids. Spheroidizing may be accomplished by heating to a temperature just below the lower critical and holding for a sufficient period of time.

Spinning
Straightening by feeding through rotating rollers or dies. The bar or wire does not rotate.

Splash
A layer of steel with uneven and rough surface formed over the bottom portion of an ingot and arises from the solidification of the spray of liquid steel reaching the mould wall due to rebound after impact on the bottom plate during early stages of teeming.

Sponge Iron
Iron obtained by solid state reaction. In this process, iron is not melted. For many centuries before blast furnace was developed around 1300 AD, sponge iron provided the main source of iron and steel. It was produced in relatively shallow hearths or in shaft-furnaces, both of which used charcoal as fuel. The product of these early smelting processes was a spongy mass of coalesced granules of nearly pure iron intermixed with considerable slag. Usable articles of wrought iron were produced by hammering the spongy mass, while still hot from the smelting operation, to expel most of the slag and compact the mass. By repeated heating and hammering, the iron was further freed of slag and forged into the desired shape.

Spooled Coil
A coil having edges that are turned up (like a spool of thread).

SR Plate
Single Reduced Plate. This product comes from the Temper Mills and goes to the Tin Mill for processing but does not get any further cold reduction.

Stability Index
A property of metallurgical coke to withstand breakage. It is expressed as the percentage of coke remaining on 1-inch screen when the coke of selected size is screened after it has been tumbled in a standard drum which is rotated for a specific time at a specific rate.

Stack Test
A full width sample of chemically treated steel saved for metallurgical testing.

Stain
A defect on the plate causing a discoloration of the plate.

Staining
Precipitation etching that causes contrast by distinctive staining of micro-constituents; different interference colors originate from surface layers of varying thickness.

Stainless Steel
The term for grades of steel that contain higher (more than 10%) chromium, with or without other alloying elements. By AISI definition, a steel is called "Stainless" when it contains 4% or more 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. The most common grades of stainless steel are:
Type 304 The most commonly specified austenitic (chromium-nickel stainless class) stainless steel, accounting for more than half of the stainless steel produced in the world. This grade withstands ordinary corrosion in architecture, is durable in typical food processing environments, and resists most chemicals. Type 304 is available in virtually all product forms and finishes.
Type 316 Austenitic (chromium-nickel stainless class) stainless steel containing 2%-3% molybdenum (whereas 304 has none). The inclusion of molybdenum gives 316 greater resistance to various forms of deterioration.
Type 409 Ferritic (plain chromium stainless category) stainless steel suitable for high temperatures. This grade has the lowest chromium content of all stainless steels and thus is the least expensive.
Type 410 The most widely used martensitic (plain chromium stainless class with exceptional strength) stainless steel, featuring the high level of strength conferred by the martensitics. It is a low-cost, heat-treatable grade suitable for non-severe corrosion applications.
Type 430 The most widely used ferritic (plain chromium stainless category) stainless steel, offering general-purpose corrosion resistance, often in decorative applications.

Stamp Charging
A process where the entire coal charge to the coke oven is stamped, or compressed, and then pushed into the oven for coking. The main advantages are : increase in bulk density of the charge, enhancement of coking properties, usage of poorer quality coking coals, production of more abrasion-resistant coke, higher yield of blast furnace-size coke and higher throughput from the ovens.

Statistical Process Control (SPC)
A technique used to predict when a steel-making 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.

Steam Blowing Process
A process that puts water droplets on steel leaving the galvanizing pot to suppress spangle formation. See Minimized Spangle and Spangle Free.

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 re-heating the steel prior to each pass, the rolls can squeeze the steel thinner per pass and impart a better surface finish.

Steel
For the purpose of classification, steel is an iron base alloy generally suitable for working to the required shape in the solid state having a carbon content generally less than 1.5 percent and containing varying amounts of other elements. A limited number of high alloyed steels may have more than 2 percent carbon but 2 percent is the usual dividing into between steel and cast iron.

Steel Drum
Center insert that keeps a coil from collapsing. Used on Double Reduced material.
Steel Insert
Small corrugated insert used to keep coils from collapsing before rewinding.

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.

Step Aging
Aging at two or more temperatures by steps, without cooling to room temperature after each step. Compare with interrupted aging and progressive aging.

Sticking
The joining up of two adjacent surfaces, due to partial welding of pack-rolled or batch-annealed sheets.

Stiffness
1. The ability of a metal or shape to resist elastic deflection.
2. The rate of stress with respect to strain; the greater the stress required to produce a given strain, the stiffer the material is said to be.

Stopper Rods
An arrangement in the ladle which controls the flow of liquid steel to the mould through the nozzle, and consists of a steel rod protected by thick cylindrical refractory sheaths.

Stoves
The regenerative stoves in which the blast air is preheated before it is delivered to the blast furnace. This decreases the amount of fuel that has to be burned in the blast furnace for each unit of hot metal and thus improves the efficiency of the process and increases the hot-metal production.

Strain
The amount of elongation or compression that occurs in a metal at a given stress or load. Generally in terms of inches elongation per inch of material.

Strain Aging
Strain aging is a type of artificial or accelerated aging which causes a change in the properties of steel that occurs gradually with time at moderately elevated temperatures after a cold working operation. Strain aging differs from quench aging in that plastic deformation is necessary before the aging process can begin. Also, unlike quench aging, a supersaturated solution of carbon or hydrogen in ferrite is not essential for strain aging. Most of the manifestations of strain aging are similar to those of quench aging - increased hardness, yield and tensile strength, reduced ductility and increased notch-impact transition temperature. In addition, strain aging has another troublesome characteristic. Low-carbon sheet steel often is temper rolled to eliminate the abrupt yield point elongation characteristic of this material. After temper rolling, the sheet can be formed with uniform yielding and related smooth contours. If aging takes place after temper rolling, the abrupt yield point returns, and the sheet is then susceptible to discontinuous yielding, fluting, and stretcher strains on subsequent deformation. Flexing the sheet by effective roller leveling just prior to forming will minimize this susceptibility.

Strain Hardening
As plastic deformation proceeds beyond yielding, new imperfections are formed and odd ones may be annihilated. At low temperatures, the overall effect is the creation of more imperfections, raising the stress required to cause further deformation. This phenomenon is known as strain hardening (or work hardening) and is typical of cold working.

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.

Stress Corrosion Cracking (SCC)
Slow growth of cracks in stainless steel caused by the combined effect of mechanical stress and exposure to a corrosive environment.

Stress Relieving
Heating to a suitable temperature, holding long enough to reduce residual stresses, then cooling slowly enough to minimize development of new stresses.

Stretcher Strains (Luder Lines)
The roughening and somewhat furrowed appearance on the surface of low carbon sheets or strips as a result of uneven spreading in the initial stages of cold-deformation after annealing, normalizing or after hot-rolling, though being not so marked in the last two cases. See Fluting.

Stretch Levelling (Patent Flattening, Stretcher Flattening)
Flattening of sheets and thereby taking away buckles, warpage, kinks, etc., by applying uniform tension at the ends gripped along the entire edge in a stretching machine.

Striation
A coating defect consisting of a series of near parallel lines or channels in the cured coating. Striation is a type of flow mark, which is caused by some contaminant, such a silicone flow-out. Striation is similar to ribbing, but striation is usually smaller in size and not always parallel.

Strip
1. 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). 2. Another name for the steel that travels through the line.

Stripping (Stripper)
The removal of an ingot from a mould after the steel has solidified. The machine used for this purpose is called a stripper.

Strip Steel
Facility which produces hot rolled bands, hot rolled and pickled bands, cold rolled steels and cold rolled bands for further processing in Sheet Mill and Tin Mill.

Structural Quality
Material applicable to the various classes of structures, indicated by the standard specifications, which is suitable for the different mechanical operations employed for the fabrication of such structures. Structural quality (the characteristics of which are defined in the standard specifications of the American Society for Testing Materials) represents the quality of steel produced under regular or normal manufacturing conditions.

Structural
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.

Sub-critical (or Process) Annealing
This consists of heating the steel to a temperature just under lower critical and holding at this temperature for the proper time (usually 2 to 4 hours) followed by air cooling.

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

Sulfide Staining
A coating defect consisting of a dark grey-black colored residue on tinplate which occurs when a break in the coating permits a high sulfur food to contact the tinplate.

Sulfurized Pickle Oil
An oiled applied at the Pickle Line (on cold reduced product only) which contains a sulfur based emulsifier which enhances lubricity in cold reduction and burn off of oil in annealing.

Sulling (Rusting)
Formation of a thin coating of hydrated oxide of iron on a coil of wire or rod obtained by keeping the coil of wire or rod obtained by keeping the coil wet by spraying water in the fine jets after pickling.

Supercooling
Cooling to a temperature below that of an equilibrium phase transformation without the transformation taking place. Also termed undercooling.

Superheater Tubes
Tubes through which the steam generated in a boiler is passed in order to raise its temperature, that is, tubes used for the conversion of saturated steam into superheated steam.

Superheating
1. Heating to a temperature above that of a phase transformation without the transformation taking place.
2. Heating molten metal to a temperature above the normal casting temperature to obtain more complete refining or greater fluidity.

Surface Finish (Tin Mill Products)
The ground roll finishes are : 7B, a smooth finish, normally for melted coatings intended for special applications; 7C, the standard mill finish, for either melted or unmelted coatings is the finish used for most applications. The blasted roll finishes are 5B, a shot blast finish (SBF) with a melted tin coating; 5C, a shot blast finish with an unmelted tin coating, principally for crowns and closures; 5D, a shot blast finish with and unmelted tin coating primarily for drawn & ironed cans.

Surface Imperfections
A superficial defect that mars the surface of steel and is detrimental to the end use; examples include blisters and roll mark defects.

Surface Inclusion
An inclusion or non-metallic particles that shows through at the surface of the steel. (See also Inclusion)

Surface Oil
Oil which is applied for corrosion protection or other special purposes.

Surface Roughness
The texture or "pattern" of a steel surface determined by the grit on the roll or the grind on a brite roll.

Swaging
Making a forging of circular section between specially shaped concave tools.

Sweep
Controlled deviation in dimensions in any particular region or place with respect to the remainder of the material. In rolls, sweep refers to the camber at the middle. In sheets, sweep refers to controlled dishing of a load of sheets for annealing to ensure flatness in the finally processed sheets.

Swift
A rotating device on which the coils of wire are placed for unwinding.