S
SAE
Abbreviation for Society of Automotive
Engineers. This organization has specified common and alloy steels and copper
base alloys in accordance with a numerical index system allowing approximation
of the composition of the metal. The last two digits always indicate the carbon
content, usually within 0.05%.
Salt Spray Test
An accelerated corrosion test in which the metal specimens are exposed to a fine mist of salt water solution either continuously or intermittently.
Scab
(Scabby)
A blemish caused on a casting by eruption of gas from the mold face or by uneven mold surface or occurring where the skin from a blowhole has partly burned away and is not welded.
Scale
The oxide of iron that forms on the surface of steel after heating.
Scaleless Blue
(See Black Oil Tempered Spring
Steel)
Scallop
(See Earing)
Scalping
Machining the surface layers from ingots,
billets and slabs before fabrication.
Scarf Joint
A butt joint in which the plane of the joint
is inclined with respect to the main axes of the members.
Scarfing
Cutting surface areas of metal objects,
ordinarily by using a gas torch. The operation permits surface defects to be cut
from ingots, billets, or the edges of plate that is to be beveled for butt
welding.
Scleroscope Hardness
(Test)
A method for measuring the hardness of
metals; a diamond-pointed hammer drops from a fixed distance through a tube onto
the smoothed metal surface and the rebound measured. The scleroscope hardness
value is empirically taken from the rebound distance, with specified high-carbon
steel as 100.
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 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 re-melted. The residual impurity of such scrap
normally relegates obsolete scrap to the mini-mills ( 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.
Scratch Brushed Finish
Finish obtained by mechanically brushing the
surface with wire bristle brushes, by buffing with greaseless compound or by
cold rolling with wire bristled rolls on scratch etched finish.
Seal weld
A weld, not being a strength weld, used to make a (sealing weld)
Sealing run
The final run deposited on the root side of a fusion (backing run)
Seam (defect)
On the surface of metal a crack that has been
closed but not welded; usually produced by some defect either in casting or in
working, such as blowholes that have become oxidized or folds and laps that have
been formed during working. Similar to cold shut and laminations.
Seam Annealing
The process of heating the seam weld at a Pipe Mill to
improve strength.
Seam Welding
An electric-resistance type of welding
process, in which the lapped sheet is passed between electrodes of the roller
type while a series of overlapping spot welds is made by the intermittent
application of electric current.
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 Hardening
Tempering certain alloy steels at certain
temperatures so that the resulting hardness is greater than that obtained by
tempering the same steel at some lower temperature for the same time.
Secondary Metal Scrap metal that has been recycled.
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.
Seconds
The designation given to sheet or strip that
has imperfections in moderate degree or extent, which may be classified in two
general groups -- imperfections in the base material, or other manufacturing
defects. This term not used in connection with non-ferrous alloys.
Segment Steel
Used for laminated piston rings. Carbon
content about .60%. Hardened and blue tempered with round edges. Hardness
usually Rockwell 30 N 68 to 71, widths vary from .058 to .163 and thicknesses
are .020, .024 and .030.
Segregation
Non-uniform distribution of alloying elements,
impurities or phases.
In an alloy, concentration of alloying
elements at specific regions, usually as a result of the primary crystallization
of one phase with the subsequent concentration of other elements in the
remaining liquid.
Segregation Banding
In homogeneous distribution of alloying
elements aligned on filaments or plates parallel to the direction of working.
Self Diffusion
The spontaneous movement of an atom to a new
site in a crystal of its own species.
Self-Hardening Steel
A steel containing sufficient carbon or
alloying element, or both, of form martensite either through air hardening or,
as in welding and induction hardening, through rapid removal of heat from a
locally heated portion by conduction into the surrounding cold metal.
Semi-finished Steel
Steel shapes—for example, blooms, billets or slabs—that later are rolled
into finished products such as beams, bars or sheet.
Semis Semi-fabricated products.
Sendzimir Mill
- WHAT
A mill having two work rolls of 1 to 2 1/2-in
diameter. each, backed up by two rolls twice that diameter and each of these backed
up by bearings on a shaft mounted eccentrically so that rotating it increases
the pressure between bearings and backup rolls.
-
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. 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.
Semikilled Steel
Steel that is incompletely deoxidized and
contains sufficient dissolved oxygen to react with the carbon to form carbon
monoxide and thus offset solidification shrinkage.
Semi-Steel
Cast iron (not steel) of high quality,
obtained by using a large percentage of steel scrap with the pig iron.
Settlement Price The official cash sellers price (offer) announced each day by the LME, which the London Clearing House uses to settle contracts.
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.
Shear Bands (deformation)
Bands in which deformation has been
concentrated in homogeneously in sheets that extend across regional groups of
grains. Usually only one system is present in each regional group of grains,
different systems being present in adjoining groups. The bands are
non-crystallographic and form on planes of maximum shear stress (55(degrees) to
the compression direction). They carry most of the deformation at large strains.
Compare microbands.
Shear
A type of cutting operation in which the metal object is cut by means of a moving blade and fixed edge or by a pair of moving blades that may be either flat or curved.
Shear Crack
A diagonal, transgranular crack caused by
shear stresses.
Shear Steel
Steel produced by forge welding together
several bars of blister steel, providing a more homogeneous product.
Shear Strength
The stress required to produce fracture in
the plane of cross section, the conditions of loading being such that the
directions of force and of resistance are parallel and opposite although their
paths are offset a specified minimum amount.
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).
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
|
Sheet
|
Sheet
|
Source: Smith Barney Inc./Salomon Brothers Inc.
Shell Molding
Forming a mold from thermosetting
resin-bonded sand mixtures brought in contact with preheated (300 to 500
(degrees) F) metal patterns, resulting in a firm shell with a cavity
corresponding to the outline of the pattern. Also called Croning process.
Shielded-Arc Welding
Arc welding in which the arc and the weld
metal are protected by a gaseous atmosphere, the products of decomposition of
the electrode covering, or a blanket of fusible flux.
Shim
A thin flat hard metal strip produced to
close tolerances; used primarily for tool, die and machine alignment purposes.
In steel there are four general types: (1) Low Carbon Rockwell B 80/100; (2)
Hard Rolled High Carbon Rockwell C 28/33. (3) Hardened and Tempered Spring Steel
Rockwell C 44/51; (4) Austenitic Stainless Steel Rockwell C 35/45. Brass shim of
commercial quality is also used and most generally specified is 2 Nos. Hard but
may be 4 Nos. Hard.
Shore Hardness (Test)
(See Scleroscope Hardness)
Short An open position for the sale of metal.
Short
Brittle.
Short Terne
A term applying to terne coated (Lead and
Tin) sheets with reference to Base Box sizes (14 x 20) Refer to terne plate.
Shortness
A form of brittleness in metal. It is
designated as cold, hot, and red, to indicate the temperature range in which the
brittleness occurs.
Shot Blasting
Cleaning surface of metal by air blast, using
metal as a result of solidification shrinkage and the progressive freezing of
metal towards the center.
Shot peening
Stressing the surface layer of a material by bombarding it with a selected
medium (usually round steel shot) under controlled conditions.
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.
Shrinkage Cavity
A void left in cast metals as a result of
solidification shrinkage and the progressive freezing of metal towards the
center.
Shrinkage groove
A shallow groove caused by contraction of the metal along each side of a
penetration bead.
Side bend test
A bend test in which the face of a transverse section of the weld is in tension
Side Trimming
This is when the sides of the strip are continually being sheared off while the
strip is being pulled into two vertical overlapping knives.
Sigma Phase
An extremely brittle Fe-Cr phase that can form at elevated temperatures in
Fe-Cr-Ni and Ni-Cr-Fe alloys.
Silicon (Si)
(Chemical symbol Si) Element No. 14 of the
periodic system; atomic weight 28.06. Extremely common element, the major
component of all rocks and sands; its chemical reactions, however, are those of
a metalloid. Used in metallurgy as a deoxidizing scavenger. Silicon is present,
to some extent, in all steels, and is deliberately added to the extent of
approximately 4% for electric sheets, extensively used in alternating current
magnetic circuits. Silicon cannot be electrodeposited.
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-Grain-Oriented
Because there is no preferential direction for
magnetization, non-grain-oriented steel is best used in rotating apparatus such
as electric motors.
Siliconizing
Diffusing silicon into solid metal, usually
steel, at an elevated temperature.
Silky Fracture
A steel fracture that has a very smooth fine
grain or silky appearance.
Silver Solders
Alloys of silver, copper, zinc and other metals, melting between 650 and 875
(degrees) C. used for making strong yet moderately ductile joints that resist
corrosion.
Single-Action Press
A forming press that operates with a single
function, such as moving a punch into a die with no simultaneous action for
holding down the bland or ejecting the formed work.
Sinker Steel
Used for making sinkers in hosiery making machinery. Supplied both hardened and
tempered and cold rolled and annealed. Usually extra precision rolled and extra
flat. Carbon content about 1.25.
Sinkhead
A reservoir insulated to retain heat and to
hold excess molten metal on top of an ingot mold, in order to feed the shrinkage
of the ingot. Also called shrink head or feeder head. (See
Hot Top)
Sintered Carbide
Composite, containing carbides of extremely
refractory metals, such as tungsten, tantalum, titanium, etc., cemented together
by a relatively low-melting metal, such as cobalt acing as a matrix.
Sintering
Converting powder into a continuous mass by
heating to a temperature considerably below fusion, usually after preliminary
compacting by pressure.
It is 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.
Skin
A thin surface layer that is different from
the main mass of a metal object, in composition, structure or other
characteristics.
Skin Pass Rolling
A light cold rolling operation that is employed to improve flatness, produce the
final surface finish or texture, develop mechanical properties, and/or reduce
the tendency of stretcher strain or fluting during forming.
Skip sequence
A welding sequence in which short lengths of run are (skip welding )
Skull
A layer of solidified metal or dross on the
wall of a pouring vessel often when metal has been poured.
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.
Slack Quenching
The process of hardening steel by quenching
from the austenitizing temperature at a rate slower than the critical cooling
rate for the particular steel, resulting in incomplete hardening and the
formation of one or more transformation products in addition to or instead of
martensite.
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.
Slag-trap
A configuration in a joint or joint preparation which may lead to the entrapment
of slag.
Slip
Plastic deformation by irreversible shear
displacement of one part of a crystal relative to another in a definite
crystallographic direction and on a definite crystallographic plane.
Slip Direction
The crystallographic direction in which
translation of slip takes place.
Slip Line
Trace of a slip plane on a viewing surface.
Slip Plane
The crystallographic plane on which slip
occurs in a crystal.
Slit
When two or more widths are obtained
from the hot rolled substrate width. The slitting operation results in a cut
edge.
Slit Edges
The edges of sheet or strip metal resulting
from cutting to width by rotary slitters.
Slitter
A processing unit that is used for side trimming or slitting into multiples.
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.
Sliver (defect)
Loose metal piece rolled down onto the
surface of the metal during the rolling operations.
Slot lap joint
A joint between two overlapping components made by depositing a fillet weld
round the periphery of a hole in one component so as to join it to the other
component exposed through the hole.
Smelter A processor of mine feed or scrap material (secondary smelter) which produces crude metal.
Soaking
Prolonged heating of a metal at selected
temperature.
Soft Skin Rolled Temper
(No. 4 Temper)
In low carbon-rolled strip steel, soft and
ductile. Produced by subjecting annealed strip to a pinch pass or skin rolling
(a very light rolling).
Solder Embrittlement
Reduction in ductility of a metal or alloy,
associated with local penetration by molten solder along grain boundaries.
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 800
(degrees) F. is generally termed brazing.
Solid Solution
A solid crystalline phase containing two or
more chemical species in concentrations that may vary between limits imposed by
phase equilibrium.
Solidus
In a constitutional diagram, the locus of
points representing the temperatures at which various components finish freezing
on cooling or begin to melt on heating.
Solute
The component of either a liquid or solid
solution that is present to the lesser or minor extent; the component that is
dissolved in the solvent.
Solution Heat Treatment
A heat treatment in which an alloy is heated
to a suitable temperature, held at that temperature long enough to cause one or
more constituents to enter into solid solution, and then cooled rapidly enough
to hold these constituents in solution.
Solution Heat Treatment
Heating an alloy to a suitable temperature,
holding at that temperature long enough to allow one or more constituents to
enter into solid solution, and then cooling rapidly enough to hold the
constituents in solution. The alloy is left in a supersaturated, unstable state,
and may subsequently exhibit quench aging.
Solvent
The component of either a liquid or solid
solution that is present to the greater or major extent; the component that
dissolves the solute.
Solvus
In a phase or equilibrium diagram, the locus
of points representing the temperature at which solid phases with various
compositions coexist with other solid phases; that is, the limits of solid
solubility.
Sorbite
Structure of steel, resulting from the
tempering of martensite. In a truly sorbitic structure, the cementite is
completely dispersed in the matrix. The trend is to call this structure tempered
martensite.
It is a fine mixture of ferrite and cementite
produced either by regulating the rate of cooling of steel or tempering steel
after hardening. The first type is very fine pearlite difficult to resolve under
the microscope; the second type is tempered martensite.
Sorbitic Pearlite
Structure of steel resulting, on cooling
under the proper conditions, from the decomposition of austenite; has a fine,
lamellar appearance.
Space Lattice (crystal)
A system of equivalent points formed by the
intersections of three sets of planes parallel to pairs of principal axes; the
space lattice may be thought of as formed by the corners of the unit cells.
Space-Centered (concerning
space lattices)
Body-centered.
Spalling
The cracking and flaking of particles out of
a surface.
Spangle
The spangle of a hot-dip
coated sheet surface is the visual manifestation of the
grains that form within the coating when it solidifies as
the sheet emerges from the pot of molten coating metal. The
spangle or grain varies in size, brightness and surface
relief, depending upon a number of factors, most of which
are related to the composition of the coating and cooling
practices.
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.
Specific Gravity
A numerical value representing the weight of
a given substance as compared with the weight of an equal volume of water, for
which the specific gravity is taken as 1.0000.
Spectograph
An optical instrument for determining the
presence or concentration of minor metallic constituents in a material by
indicating the presence and intensity of specific wave lengths of radiation when
the material is thermally or electrically excited.
Spelter (Prime Western
Spelter)
A low-grade of Virgin Zinc containing approximately 98% Zinc used in Galvanizing
processes.
Spherodizing
Heating and cooling to produce a spherical
or globular form of carbide in steel.
Spherodizing methods frequently used are:
1. Prolonged holding at a temperature just below Ae1. .
2. Heating and cooling
alternately between temperatures that are just below Ae1. .
3. Heating to
temperature above Ae1 or Ae3 and then cooling very slowly in the furnace or
holding at a temperature just below Ae1. .
4. Cooling at a suitable rate from
the minimum temperature at which all carbide is dissolved, to prevent the
reformation of a carbide network, and then re-heating in accordance with methods
1 or 2 above. (Applicable to hypereutectoid steel containing a carbide network.
Spherodizing Annealing
A subcritical annealing treatment intended to
produce spherodization of cementite or other carbide phases.
Spherodized Structure
A microstructure consisting of a matrix
containing spheroidal particles of another constituent.
Spiegel
High-manganese pig iron, containing 15-30%
manganese, approximately 5% carbon, and less than 1% silicon used in the
manufacture of steel by the Bessemer, or basic open-hearth process.
Spinning
The procedure of making sheet metal discs into hollow shapes by pressing the
metal against a rotating form (spinning chuck) by a tool.
Spot Market
Sales for delivery in less than three months.
Spot Welding
Welding of lapped parts in which fusion is
confined to a relatively small circular area. It is generally resistance
welding, but may also be gas-shielded tungsten-arc, gas-shielded metal-arc, or
submerged-arc welding.
It is an electric-resistance welding process in
which the fusion is limited to a small area. The pieces being welded are pressed
together between a pair of water-cooled electrodes through which an electrical
current is passed during a very short interval so that fusion occurs over a
small area at the interface between the pieces.
Spray transfer
Metal transfer which takes place as globules of diameter substantially larger
than that of the consumable electrode from which they are transferred.
Spread b A term referring to the difference in two prices. The contango or backwardation between two prompt dates or the difference between the bid and offer price.
Spring Steel
Steel, normally of the high-carbon or alloy type, used in the manufacture of springs, lending itself to appropriate heat treatment; usually made is the open hearth or electric furnace.
Spring Steel Strip
Any of a number of strip steels produced for
use in the manufacture of steel springs or where high tensile properties are
required marketed in the annealed state, hard rolled or as hardened and tempered
strip.
Spring Temper
In brass mill terminology, Spring Temper is
eight numbers hard or 60.50% reduction.
Spring-Back
An indicator of elastic stresses, frequently
measured as the increase in diameter of a curved strip after removing it from
the mandrel about which it was held. The measurement is employed as an indicator
of the extent of recovery or relief of residual stresses that has been achieved
by the transformation of elastic strain to plastic strain during heating or
stress relieving.
Stabilizing Annealing
A treatment applied to austenitic stainless
steels that contain titanium or columbium. This treatment consists of heating to
a temperature below that of a full anneal in order to precipitate the maximum
amount of carbon at titanium carbide or columbium carbide. This eliminates
precipitation at lower temperatures, which might reduce the resistance of the
steel to corrosion.
Stabilizing Treatment
Any treatment intended to stabilize the
structure of an alloy of the dimensions of a part.
(1) Heating austenitic
stainless steels that contain titanium, columbium, or tantalum to a suitable
temperature below that of a full anneal in order to inactivate the maximum
amount of carbon by precipitation as a carbide of titanium, columbium, or
tantalum.
(2) Transforming retained austenite in parts made from tool steel.
(3)
Precipitating a constituent from a nonferrous solid solution to improve the
workability, to decrease the tendency of certain alloys to age harden at room
temperature, or to obtain dimensional stability.
Stack cutting
The thermal cutting of a stack of plates usually clamped together.
Staggered intermittent weld
An intermittent weld on each side of a joint (usually fillet welds in T and lap
joints) arranged so that the welds on one side lie opposite the spaces on the
another side along the joint.
Stain Finish
(See Scratch Brushed Finish)
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. 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 martensitic. 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.
Stamping
A term used to refer to various press forming
operations in coining, embossing, blanking, and pressing.
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.
Steam Blued
(See Bluing)
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
An iron-base alloy, malleable in some
temperature range as initially cast, containing manganese, usually carbon, and
often-other alloying elements. In carbon steel and low-alloy steel, the maximum
carbon is about 2.0%; in high-alloy steel, about 2.5%. The dividing line between
low-alloy and high-alloy steels is generally regarded as being at about 5%
metallic alloying elements. Steel is to be differentiated from two general
classes of irons: the cast irons, on the high-carbon side, and the relatively
pure irons such as ingot iron, carbonyl iron, and electrolytic iron, on the
low-carbon side. In some steels containing extremely low carbon, the manganese
content is the principal differentiating factor, steel usually containing at
least 0.25%; ingot iron contains considerably less.
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 Strapping
Banding and packaging material that is used to close and reinforce shipping
units, such as bales, boxes, cartons, coils, crates, and skids.
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.
Sterling Silver
A silver alloy containing at least 95.2% Ag,
the remainder being unspecified but usually copper.
Sticker
Steel sheets or strip adhering. Usually by
fusion spots caused by overheating during box annealing.
Stockist A distributor of semi-fabricated products who holds stock for sale to consumers.
Straight-Chrome
An iron alloy. A term indicating a group of
stainless steels the principal alloying element of which is chromium in varying
amounts from 4.00 to 27.00%.
Strain
A measure of the change in the size or shape
of a body, referred to its original size or shape. Linear strain is the change
per unit length of a linear dimension. True strain (or natural strain) is the
natural logarithm of the ratio of the length at the moment of observation to the
original gauge length. Conventional strain is the linear strain referred to the
original gauge length. Shearing strain (or shear strain) is the change in angle
(expressed in radians) between two lines originally at right angles. When the
term strain is used alone it usually refers to the linear strain in the
direction of the applied stress.
Strain Aging
Aging induced by cold work.
Strain Hardening
An increase in hardness and strength caused
by plastic deformation at temperatures below the re-crystallization range.
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
Deforming force to which a body is subjected or the resistance which the body offers to deformation by the force.
Stress-Cracking
Occurs during the thermal cutting of high carbon and alloy steels at the cut
edges. proper processing, which may include preheating, will prevent this
problem
Stress-Corrosion Cracking
Failure by cracking under the combined action of corrosion and stress, either
external (applied) or internal (residual). Cracking may be either intergranular
or transgranular, depending on the metal and the corrosive medium.
Stress Relief
Low temperature annealing for removing
internal stresses, such as those resulting on a metal from work hardening or
quenching.
Stress Relieving
Heating to a suitable temperature, holding
long enough to reduce residual stresses and then cooling slowly enough to
minimize the development of new residual stresses.
Stress-Rupture Test
A tension test performed at constant
temperature, the load being held at such a level as to cause rupture. Also known
as creep-rupture test.
Stretch Forming
A process of forming panels and cowls of
large curvature by stretching sheet over a form of the desired shape. This
method is more rapid than hammering and beating.
Stretcher Leveling
Leveling where a piece of metal is gripped at
each end and subjected to a stress higher than its yield strength to remove warp
and distortion. Sometimes called patent leveling.
It is a method of making metal sheet or strip dead
flat by stretching.
Stretcher Straightening
A process for straightening rod, tubing, and
shapes by the application of tension at the ends of the stock. The products are
elongated a definite amount to remove warpage.
Stretcher Straining
Steel pulled beyond its yield point leaving a distorted surface; also called
coil breaks.
Stretcher Strains
Elongated markings that appear on the surface
of some materials when deformed just past the yield point. These markings lie
approximately parallel to the direction of maximum shear stress and are the
result of localized yielding Same as Luders lines.
Striking voltage
The minimum voltage at which any specified arc may be initiated.
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 ).
Strip Steel (cold rolled)
A flat cold rolled steel product (Other than
Flat Wire) 23 15/16 and narrower; under .250 in thickness, which has been cold
reduced to desired decimal thickness and temper on single stand, single stand
reversing, or tandem cold mills in coil form from coiled hot rolled pickled
strip 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.
Structural Steel Sheet
When this term is applied to steel
sheet, it refers to the designation that is used for steel sheet that is
produced to meet a specific level of strength and formability. The formability
is expressed as percent elongation in a tensile test. Structural Steel is
typically used for applications where the strength of the sheet is an important
design criterion, i.e., load-bearing applications.
Structure
The arrangement of parts; in crystals,
especially, the shape and dimension of the until cell, and the number, kinds and
positions of the atoms within it.
Sub-boundary Structure (subgrain
structure)
A network of low-angle boundaries (usually
with misorientations or less than one degree) within the main grains of a
microstructure.
Subcritical Annealing
An annealing treatment in which a steel is
heated to a temperature below the A1 temperature and then cooled slowly to room
temperature.
Subgrain
A portion of a crystal or grain slightly
different in orientation from neighboring portions of the same crystal.
Generally, neighboring subgrains are separated by low-angle boundaries.
Submerged-arc welding
Metal-arc welding in which a bare wire electrode or electrodes are used; the arc
or arcs are enveloped in a flux, some of which fuses to form a removable
covering of slag on the weld.
Substitutional Solid
Solution
A solid solution in which the solvent and
solute atoms are located randomly at the atom sites in the crystal structure of
the solution.
Substrate
The layer of metal underlying a coating,
regardless of whether the layer is base metal.
Raw material used as an input for steel processing: For example, hot-rolled
steel is the substrate for cold-rolling operations.
Sulfidation
The reaction of a metal or alloy with a sulphur-containing species to produce a
sulphur compound that forms on or beneath the surface of the metal or alloy.
Sulfide Stress Cracking
Cracking of a metal under the combined action of tensile stress and corrosion in
the presence of water and hydrogen sulphide (a form of hydrogen stress
cracking.)
Sulfur (S)
(Chemical symbol S)
Element No. 16 of the periodic system; atomic weight 32.06. Non-metal occurring in a number of allotropic modifications, the most common being a pale-yellow brittle solid. In steel most commonly encountered as an undesired contaminant. However, it is frequently deliberately added to cutting stock to increase machinability.
Superalloy
An alloy developed for very high temperature
service where relatively high stresses (tensile, thermal, vibratory, and shock)
are encountered and where oxidation resistance is frequently required.
Supercooling
Cooling to a temperature below that of an
equilibrium phase transformation without the transformation taking place.
Superficial Rockwell
Hardness Test
Form of Rockwell hardness test using
relatively light loads which produce minimum penetration. Used for determining
surface hardness or hardness of thin sections or small parts, or where large
hardness impression might be harmful.
Surface-fusion welding
Gas welding in which a carburizing flame is used to melt the surface of the
parent metal which then unites with the metal from a suitable filler rod.
Sustained backfire
Retrogression of the flame into the blowpipe neck or body the flame remaining
alight.
Note: This manifests itself either as "popping" or "squealing" with a
small pointed flame issuing from the nozzle orifice or as a rapid series of
minor explosions inside.
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