शब्दावली


A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
Abrasive
A substance capable of removing material from another substance in
machining, abrasion or polishing.
Abrasive Wear
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.
Abrasion
The process of grinding or wearing away through the use of abrasives, a
roughening or scratching of a surface due to abrasive wear.
Abrasion Rate
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.
Accelerated Cooling
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.
Acid Bottom
Furnace bottom (hearth) of a melting furnace made of acid refractory such
as silica bricks.
Acid Brittleness
Brittleness induced in sheet and strip pickled in acid solution to remove
scale or during electroplating. This is commonly attributed to absorption
of hydrogen.
Acid Fluxes
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.
Acid Process
A steel making process in which steel is refined under an acid slag in an
acid refractory lined furnace or converter.
Acid Refractory
A refractory material, acidic in chemical composition and containing high
proportion of silica, that is, silica sand and ganister.
Acid Steel
Steel made by acid process.
Adhesive Wear
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 that supplies the
force to the A.G.C. roll force cylinders.
Age Hardening
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.
Aging
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.
Agglomerating Processes
Fine particles of limestone (flux) and iron ore are difficult to handle and
transport because of dusting and decomposition, so the powdery material
usually is processed into larger pieces. The raw material's properties
determine the technique that is used by mills. 
Sinter Baked particles that stick together in roughly one-inch chunks.
Normally used for iron ore dust collected from the blast furnaces. 
Pellets Iron ore or limestone particles are rolled into little balls in a
balling drum and hardened by heat. 
Briquettes Small lumps are formed by pressing material together. Hot Iron
Briquetting (HBI) is a concentrated iron ore substitute for scrap for use
in electric furnaces. 
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.
Air Hardening
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 United
States.
Alkaline Cleaner
Uses an alkaline solution, usually sodium hydroxide, to clean residual oils
and iron fines left on the strip from the cold reduction process.
Alkyd
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 outside decoration.
Alligatoring
The longitudinal splitting of flat slabs in a plane parallel to the rolled
surface. Also known as fishmouthing.
Alloy
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.
Alloying Element
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.
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.
Alloy Surcharge
The addition to the producer's selling price included in order to offset
raw material cost increases caused by higher alloy prices.
Alumina
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.
Anneal
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 Batch Anneal.
Annealing
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
diffusion process.
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 cooled. 
(2) Continuous. Normally part of a coating line, the steel is uncoiled and
run through a series of vertical loops within a heater: The temperature and
cooling rates are controlled to obtain the desired mechanical properties
for the steel. 
The various annealing processes are : full annealing, sub-critical (or
process) annealing, isothermal annealing and spheroidization annealing.
Anneal to Temper
A final partial anneal that softens a cold worked non-ferrous alloy to a
specified level of hardness or tensile strength.
Anodes
Tin bars that are put in the plater cells and are important to the plating
process in the Tin Mill.
API
American Petroleum Institute.
Arc Heating
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 Rinse
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.
Argon Trim
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 nm3/min.
Argon Stir
To achieve slag-metal mixing in ladle desulphurization of steel during
refining, the argon is blown through the melt at a rate of 0.3-0.5 nm3/min.
Artificial Aging
Aging above room temperature.
ASTM
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.
ASTM Standards
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.
Atmosphere Valve
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 process.
Atomizing Steam
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 from plugging.
Attemperator
Header connecting the primary and finishing superheaters into which feed
water is sprayed to control the final temperature of the steam leaving the
boiler.
Austempering
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.
Austenite
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.
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.
Automatic
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 breaking.
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 speed.
Auxiliary Pump
Pump on the auxiliary system which supplies the pressure for the system.
AW-100
The hydraulic oil used in all the hydraulic systems located in the
finishing mill oil cellar and the furnace hydraulic system.
Alloy Steel
An iron-based mixture is considered to be an alloy steel when manganese is
greater than 1.65%, silicon over 0.5%, copper above 0.6%, or other minimum
quantities of alloying elements such as chromium, nickel, molybdenum,
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.
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 purposes. 
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.
Go to Top
Copyright © 2012 SAIL, all rights reserved
Designed & Developed by Cyfuture