A substance capable of removing material from another substance in machining, abrasion or polishing.
The removal or displacement of materials from a surface when hard
particles slide or roll across the surface under pressure. The particles
may be loose or may be part of another surface in contact with the
surface being worn.
The process of grinding or wearing away through the use of
abrasives, a roughening or scratching of a surface due to abrasive wear.
The rate which material is removed from the surface during
abrasion. It is usually expressed in terms of thickness removed per unit
of time or distance traversed.
Employed to improve resistance to impact (toughness) and refine
the grain size of certain grades and thickness of plates. Such cooling
is accomplished by fans to provide circulation of air during cooling, or
by a water spray or dip.
Furnace bottom (hearth) of a melting furnace made of acid refractory such as silica bricks.
Brittleness induced in sheet and strip pickled in acid solution to
remove scale or during electroplating. This is commonly attributed to
absorption of hydrogen.
Used to remove unwanted basic impurities to form a fusible slag.
Silica (SiO2), available as sand, gravel, and quartz in large quantities
and in a sufficiently pure state, is the only substance that is used as
a strictly acid flux.
A steel making process in which steel is refined under an acid slag in an acid refractory lined furnace or converter.
A refractory material, acidic in chemical composition and
containing high proportion of silica, that is, silica sand and ganister.
Steel made by acid process.
The removal or displacement of materials from a surface by the
welding together and subsequent shearing of minute areas of two surfaces
that slide across the surface under pressure. In advance stages, may
lead to galling.
Adjustable Mould Width
In order to minimize both the time required to change a mould as
well as the mould inventory during slab casting, adjustable mould were
first developed which could be adjusted without the mould being removed
from the casting machine. More recently, as an alternative to slab
slitting, the slab width can be changed during the actual operation. In
one design, the mould taper can be adjusted by using different gear
ratios for moving the top and bottom of the narrow mould faces.
A. G. C. System
(Automatic Gauge Control) Hydraulic or electric system th at supplies the force to the A.G.C. roll force cylinders.
A process of aging at atmospheric temperature that increases
hardness and strength and ordinarily decreases ductility gradually. Age
hardening usually follows rapid cooling or cold working. Takes effect on
all cold rolled sheets in storage except fully aluminum killed.
A change in the properties of certain metal and alloys (such as
steel) that occurs gradually with time at atmospheric temperatures
(natural aging) or more rapidly at moderately elevated temperatures
(artificial or accelerated aging) after a hot working heat treatment or
cold working operation. Artificial aging refers to : quench aging (aging
following quenching) and strain aging (aging induced by cold-working).
Typical properties impacted are: hardness, yield strength, tensile
strength, ductility, impact value, formability, magnetic properties,
etc. See also Non-aging and artificial aging.
Fine particles of limestone (flux) and iron ore are difficult to
handle and transport because of dusting and decomposition, so the
powdery material usually is processed into larger pieces. The raw
material's properties determine the technique that is used by mills.
Sinter Baked particles that stick together in roughly one-inch
chunks. Normally used for iron ore dust collected from the blast
Pellets Iron ore or limestone particles are rolled into little balls in a balling drum and hardened by heat.
Briquettes Small lumps are formed by pressing material together.
Hot Iron Briquetting (HBI) is a concentrated iron ore substitute for
scrap for use in electric furnaces.
Nodules Fine iron bearing materials moving through a rotary kiln
are formed into nodules or lumps by the rolling of the charge heated to
incipient fusion temperatures.
Hardening by cooling in air or gas at ambient temperature from a temperature above the transformation range.
Air Heater Tubes
Tubes used for heating air by means of hot gases, the air passing either inside or outside the tubes.
AISI (American Iron and Steel Institute)
An association of North American companies that mine iron ore and
produce steel products. There are 50 member companies and more than 100
associate members, which include customers that distribute, process, or
consume steel. The AISI has reorganized into a North American steel
trade association, representing the interests of Canada, Mexico, and the
Uses an alkaline solution, usually sodium hydroxide, to clean
residual oils and iron fines left on the strip from the cold reduction
A type of resin made from a polyhydroxy alcohol combined
chemically with the acids of various oils. They are particularly adapted
for use where hardness and high gloss are required. Used largely for
The longitudinal splitting of flat slabs in a plane parallel to the rolled surface. Also known as fishmouthing.
A substance having metallic properties consisting of two or more
elements in which the major constituent is metal, or of metallic and
non-metallic elements which are miscible with each other when molten,
and have not separated into distinct layers when solid.
An element (metal or non-metal) added during the making of steel
for the purpose of increasing corrosion resistance, hardness, or
strength. The metals used most commonly as alloying elements in
stainless steel include chromium, nickel, and molybdenum.
An iron-based mixture is considered to be an alloy steel when
manganese is greater than 1.65%, silicon over 0.5%, copper above 0.6%,
or other minimum quantities of alloying elements such as chromium,
nickel, molybdenum, vanadium, lead, niobium or tungsten are present. An
enormous variety of distinct properties can be created for the steel by
substituting these elements in the recipe.
Alloy Tool Steels
The principle functions of the alloying elements in tool steels
are to increase hardenability ; to form hard, wear-resistant alloy
carbides; and to increase resistance to softening on tempering. The
alloy tool steels may be roughly classified according to the extent of
their utilization of these three functions :
1. Relatively Low-alloy Tools Steels : These are
of higher hardenability that the plain carbon tool steels in order that
they may be hardened in heavier sections or with less drastic quenches
and thereby less distortion.
2. Intermediate Alloy Tool Steels : These steels
usually contain elements such as tungsten, molybdenum or vanadium,
which form hard, were-resistant carbides.
3. High-speed Tool Steels : These contain large
amounts of the carbide-forming elements which serve not only to furnish
wear-resisting carbides but also to promote secondary hardening and
thereby to increase resistance to softening at elevated temperature.
The addition to the producer's selling price included in order to
offset raw material cost increases caused by higher alloy prices.
Aluminium oxide (Al2O3), a common constituent of many refractory materials used in steel making.
Aluminum Killed Steel (Special Killed)
Steel deoxidized with aluminum in order to reduce the oxygen
content to a minimum so that no reaction occurs between carbon and
oxygen during solidification.
A process, consisting of heating to and holding at a suitable
temperature followed by cooling at a suitable rate, used primarily to
soften metallic materials, such as steel. This process also
simultaneously produces desired changes in microstructure, as in other
properties, such as improvement of mechanical or electrical properties,
removing stresses, increase in stability in dimensions, facilitation of
cold work, improving machinability, etc. Also see Continuous Anneal and
What A heat or thermal treatment process by which a previously
cold-rolled steel coil is made more suitable for forming and bending.
The steel sheet is heated to a designated temperature for a sufficient
amount of time and then cooled.
Why The bonds between the grains of the metal are stretched when a
coil is cold rolled, leaving the steel brittle and breakable. Annealing
re-crystallizes the grain structure of steel by allowing for new bonds
to be formed at the high temperature. Annealing may be done to induce
softness, improving machinability, improving cold-working properties,
obtaining a desired structure, reducing stresses and to facilitate
How There are two ways to anneal cold-rolled steel coils : batch and continuous.
(1) Batch (Box). Three to four coils are stacked on top of each
other, and a cover is placed on top. For up to three days, the steel is
heated in a non-oxygen atmosphere (so it will not rust) and slowly
(2) Continuous. Normally part of a coating line, the steel is
uncoiled and run through a series of vertical loops within a heater: The
temperature and cooling rates are controlled to obtain the desired
mechanical properties for the steel.
The various annealing processes are : full annealing, sub-critical
(or process) annealing, isothermal annealing and spheroidization
Anneal to Temper
A final partial anneal that softens a cold worked non-ferrous alloy to a specified level of hardness or tensile strength.
Tin bars that are put in the plater cells and are important to the plating process in the Tin Mill.
American Petroleum Institute.
A method of heating steel by electric current in which the current
is passed through an ionized gaseous medium and the heat radiated by
the arc generated is utilized. This practice can be applied through two
methods : (a) arcs pass between electrodes supported in the furnace
above the metal. In this method, known as indirect-arc heating, the
metal is heated solely by radiation from the arcs. Or, (b) arcs pass
from the electrodes to the metal. In this method, known as direct-arc
heating, the current flows through the metal charge so that the heat
developed by the electrical resistance of the metal, though relatively
small in amount, is added to that radiated from the arcs.
Argon-Oxygen Decarburization (AOD)
What A process for further refinement of stainless steel through reduction of carbon content.
Why The amount of carbon in stainless steel must be lower than
that in carbon steel or lower alloy steel (i.e., steel with alloying
element content below 5%). While electric arc furnaces (EAF) are the
conventional means of melting and refining stainless steel, AOD is an
economical supplement, as operating time is shorter and temperatures are
lower than in EAF steel making. Additionally, using AOD for refining
stainless steel increases the availability of the EAF for melting
How Molten, unrefined steel is transferred from the EAF into a
separate vessel. A mixture of argon and oxygen is blown from the bottom
of the vessel through the melted steel. Cleaning agents are added to the
vessel along with these gases to eliminate impurities, while the oxygen
combines with carbon in the unrefined steel to reduce the carbon level.
The presence of argon enhances the affinity of carbon for oxygen and
thus facilitates the removal of carbon.
To homogenise the melt temperature and composition and also to
assist the flotation of deoxidation products during ladle refining of
steel, the argon is blown through the melt at a rate of 0.08-0.13
nm3/min for 3 to 5 minutes.
To facilitate the dissolution of ladle additions during refining
of steel, the argon is blown through the melt at a rate of 0.30-0.45
To achieve slag-metal mixing in ladle desulphurization of steel
during refining, the argon is blown through the melt at a rate of
Aging above room temperature.
American Society for Testing and Materials. A non-profit
organization that provides a forum for producers, users, ultimate
consumers, and those having a general interest (representatives of
government and academia) to meet on common ground and write standards
for materials, products, systems, and services.
A series of documents, approved and published by ASTM, that
include specifications or requirements, practices, guides, test methods,
etc., covering various materials, products, systems or services. In the
steel industry, the steel related ASTM standards are used by both the
producers and users to ensure that a steel product or service meets all
intended requirements. See American Society for Testing and Materials.
A valve that is located in the exhaust line of a turbine and is
designed to open up and get a positive pressure in the exhaust line.
Atomic Hydrogen Welded Tube
Tube made by forming strip, usually of stainless or heat-resisting
steel, into tubular form and welding the joint by the atomic hydrogen
Low pressure steam which is introduced to the oil gun to help
atomize the oil, to assist the burning process, and to keep the oil gun
Header connecting the primary and finishing superheaters into
which feed water is sprayed to control the final temperature of the
steam leaving the boiler.
Cooling (quenching) an austenitised steel at a rate high enough to
suppress formation of high temperature transformation products, then
holding the steel at a temperature below that for pearlite formation and
above that for martensite formation until transformation to an
essentially bainitic structure is complete.
Generally a solid solution of one or more alloying elements in a
face centered cubic polymorph of iron (g iron). Specifically, in carbon
steels , the interstitial solid solution of carbon g iron.
The largest category of stainless steel, generally non-magnetic,
accounting for about 70% of all production. Refers to a particular grain
structure of steel which in normal steel exists at high temperature. In
stainless steel, this structure exists at room temperature and imparts
certain characteristic properties. The austenitic class offers the most
resistance to corrosion in the stainless group, owing to its substantial
nickel content and higher levels of chromium. Austenitic stainless
steels are hardened and strengthened through cold working (changing the
structure and shape of steel by applying stress at low temperature)
instead of by heat treatment. Ductility (ability to change shape without
fracture) is exceptional for the austenitic stainless steels. Excellent
weldability and superior performance in very low-temperature services
are additional features of this class. Applications include cooking
utensils, food processing equipment, exterior architecture, equipment
for the chemical industry, truck trailers, and kitchen sinks. The two
most common grades are type 304 (the most widely specified stainless
steel, providing corrosion resistance in numerous standard services) and
type 316 (similar to 304 with molybdenum added, to increase opposition
to various forms of deterioration).
Austenitic Grain Size
The size attained by the grains in steel when heated to the
autenitic region. This may be revealed by appropriate etching of cross
sections after cooling to room temperature.
Describes the status of the operation when the O2 pulpit has control and the boiler logic has control.
Automatic Gauge Control
Using hydraulic roll force systems, steel makers have the ability
to control precisely their steel sheet's gauge (thickness) while it is
traveling at more than 50 miles per hour through the cold mill. Using
feedback or feed-forward systems, a computer's gap sensor adjusts the
distance between the reduction rolls of the mill 50-60 times per second.
These adjustments prevent the processing of any off-gauge steel sheet.
The principal components of a computerised AGC are :
1. Mathematical models that adequately describe the process.
2. Instrumentation to measure the required variables of the system.
3. Control equipment, including a digital computer, to perform the required functions for control of the system.
Auto Stamping Plant
A facility that presses a steel blank into the desired form of a
car door or hood, for example, with a powerful die (pattern). The steel
used must be ductile (malleable) enough to bend into shape without
Auxiliary Hydraulic System
Hydraulic system that supplies the force to run the various
hydraulic cylinders associated with the finishing mill which are not
taken care of by the A.G.C. or C.V.C. Hydraulic systems.
Auxiliary Oil Pump
A steam or electric pump that maintains oil pressure on the
controls and the bearings of a turbo blower when it is not up to maximum
Pump on the auxiliary system which supplies the pressure for the system.
The hydraulic oil used in all the hydraulic systems located in the
finishing mill oil cellar and the furnace hydraulic system.