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 Marks
Patches of furnace refractory material embedded on the surface of hot steel
and rolled subsequently.
Irregular shaped patches of metal on ingot surface arising from cavities in
mould walls or caused by loosely adhering layers of metal.
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.
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.
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
Screw Stock
Free cutting steel bars suitable for the manufacture of bolts and screws.
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.
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.
A hot rolled product widely used for structural purposes, with a
cross-section of special contour. The common types are equal and unequal
angles, bulb plate and angle, channel, round, square, flat, beam, tee bar,
zed bar etc.
Section Tubes
Tube with a cross section other than circular.
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.
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
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
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).
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.
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 and Sheet Mill, majority is cold reduced at Tandem
4. Electro-galvanized : Zinc coated, normally lighter gauge than
galvanized, processed through Strip Steel and Tin Mill, mostly single
reduced. (Tandem)
Sheet Slab
A slab of suitable size for rolling into sheet.
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.
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
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.
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.
Silicon dioxide (SiO2) occurring in nature as sand and ganister, with
varying amounts of other impurities. It is used as an acid refractory.
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
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.
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
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).
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.
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.
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.
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
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.
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.
1. Area on the Pickler where the strip is side-trimmed (slit) to its proper
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.
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 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.
A link which has been drawn tight in a wire.
When hairline cracks are exposed by fracturing, they appear as bright
crystalline areas of almost circular form, sometimes known as snowflakes.
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
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.
The cracking and flaking of metal particles out of a surface.
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
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.
The chemical composition and dimensions of products made by the plant. The
specifications include all processes required to achieve the finished
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.
Straightening by feeding through rotating rollers or dies. The bar or wire
does not rotate.
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
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
A defect on the plate causing a discoloration of the plate.
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
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.
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
Steel Insert
Small corrugated insert used to keep coils from collapsing before
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
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 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
The joining up of two adjacent surfaces, due to partial welding of
pack-rolled or batch-annealed sheets.
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.
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
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
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.
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
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.
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.
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
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.
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.
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.
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 and 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.
Making a forging of circular section between specially shaped concave
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
A rotating device on which the coils of wire are placed for unwinding.
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