I-Beams - Structural sections on which the flanges are tapered and are typically not as long as the flanges on wide-flange beams. The flanges are thicker at the cross sections and thinner at the toes of the flanges. They are produced with depths of 3-24 inches.

I.D. Fan - (I.D. fan) Steam turbine or electric motor driven fan which develops negative draft within the boiler to pull the hot exhaust gases through the boiler.

ICI - Investment Casting Institute

ID - Inside diameter (of a coil).

ID Grinding - Term for internal (dimension) grinding.

Ideal Critical Diameter, D1 - The largest diameter of a bar which, upon quenching in an ideal quench, will exhibit 50% martensite at the center of the bar.

Ideal Quench - A quench in which the temperature of an object being quenched instantaneously drops to that of the quench bath and remains constant.

Independent Chuck - A chuck in which each jaw may be moved independently of the others.

Index Plate - A metal disk or plate punched with many holes arranged in a series of rings. One outside the other each ring containing a different number of holes.

Indexing - The praocess of positioning a workpiece for maching it into equal spaces. Dimensions or angles using an index or dividing head.

Indexing Fixture - A complete indexing unit composed of dividing head and rootstock.

Idle Pump - A pump on an oil system that is not being used. The pump's selection button is in the off mode.

Idler - A gear or gears placed between two other gears to transfer motion from one fear to the other gear without changing their speed or ratio.

Ignition Furnace Fan - A small series of fans used to mix air with gas for the ignition of the furnace.

Ignitors - Devices which employ a high-energy electrical spark to ignite the pilot gas flame.

Illinois Inclusion Count Method - A determination of the index number of cleanliness of steel.

Illite - A mineral, typically KAl3Si3O10(OH)2, found in many clays, large working of which are found in Illinois and Michigan.

IMIS - Integrated Manufacturing Information System.

Immersed Scanning - In ultrasonics, a planned, systematic movement of the beam relative to the object being inspected, the search unit being coupled to this object through a column of liquid. In most cases the object and the search unit are submerged in water.

Impact - A part formed in a confining die from a metal slug, usually cold, by rapid single stroke application of force through a punch, causing the metal to flow around the punch and/or through an opening in the punch or die.

Impact Energy (Impact Value) - The amount of energy required to fracture a material, usually measured by means of an Izod or Charpy test. The type of speciment and testing conditions affect the values and therfore should be specified.

Impact Strength - "The resistance to impact loads; usually expressed as the foot pounds of energy absorbed in breaking a standard specimen. See Charpy Impact Test. "

Impact Test - A test for determining the behavior of materials when subjected to high rates of loading under conditions designed to promote fracture, usually in bending, tension or torsion. The quantity measured is the energy absorbed when the specimen is broken by a single blow.

Impoverishment - Loss of any constituent from an alloy or from localized areas of an alloy by oxidation, liquidation, volatilization, or changes in the solid state. The term depletion is also used, particularly in referring to the lowering of the concentration of solute in a solid solution, around particles precipitated from solid solution.

Impregnation - The treatment of castings with a sealing medium to stop pressure leaks, such as soaking under pressure with or without prior evacuation and either with hot or cold application. Mediums used include silicate of soda, drying oils with or without styrene, plastics, and proprietary compounds.

Impression Die Forging - A forging that is formed to the required shape and size by machined impressions in specially prepared dies that exert three-dimensional control on the work piece.

Impurity - An element unintentional allowed in a metal or alloy. Some impurities have little effect on properties; others will grossly damage the alloy.

In - Chemical symbol for Indium

In Service - Term that means "in use".

Inboard Bearing - Pump bearing that is nearest the driver.

Inclusion - Impurities in metal, usually in the form of particles in mechanical mixture.

Inclusion Count - A method of assessing the number and size of non-metallic inclusions present in metal.

Inclusions - Particles of impurities (usually oxides, sulfides, silicates, etc.) that are held mechanically or are formed during the solidification or by subsequent reaction within the solid metal.

Inclusion, Stringer - An impurity, metallic or non-metallic, which is trapped in the ingot and elongated subsequently in the direction of working. It may be revealed during working or finishing as a narrow streak parallel to the direction of working

Incomplete seam - See weld, incomplete

Inconel - An oxidation-resistant alloy, 80% Ni, 14% Cr, and 6% Fe.

Indentation Hardness - "The resistance of a material to indentation. This is the usual type of hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load. See Brinell Hardness and Hardness "

Index Start - Start time for the first coil processed on a new index number.

Indirect-Arc Furnace - An AC (Alternating Current) electric-arc furnace in which the metal is not one of the poles.

Indium - Chemical symbol In. Grayish-white minor metal obtained by treating smelter flue dusts and slags or other residue of base metal concentrates. Capable of marking paper (just as lead does), indium is used in low-melting alloys, solders,electrical contact coatings,infrared detectors,nuclear reactor control rods, and various electonic components.

Induction Furnace - A AC melting furnace which utilizes the heat of electrical induction.

Induction Hardening - A widely used process for the surface hardening of steel. The components are heated by means of an alternating magnetic field to a temperature within or aboved the transformation range followed by immediate quenching. The core of the component remains unaffected by the treatment and its physical properties are those of the bar from which it was machined, whilst the hardness of the case can be within the range 37/58 Rc. Carbon and alloy steels with a carbon content in the range 0.40/0.45% are most suitable for this process.

Induction Heating - Process of heating by electrical resistance and hysteresis losses induced by subjecting a metal to the varying magnetic field surrounding a coil carrying an alternating current.

Inert Gas - A gas that will not support combustion or sustain any chemical reaction; e.g., argon or helium.

Infrared Dryer - A core or mold dryer employing infrared lamps.

Infrared Radiation Pyrometer - This instrument which uses the ratio of the radiated energy from a body in two wavelength bands and then is a measure of the body's surface temperature. Temperatures down to 200 C (392 F) may be measured.

Infrared Rays - Pertaining to or designating those rays which lie just beyond the red end of the visible spectrum, such as are emitted by a hot non-incandescent body. They are invisible and nonactinic and are detected y their thermal effect. Their wave lengths are longer than those of visible light and shorter than those of radio waves. Can be applied in the foundry for drying or core baking operations and for heating dies. Infrared radiant heat are synonymous.

Infusorial Earth (Diatomite, Fossil Flour, Mountain Meal, Mountain Flour, Tripolite, Kieselguhr) - A very fine whitish powder composed of the siliceous skeletons of infusorians (Protozoa).

Ingates - "The channels through which molten metal enters the mold cavity. See Gate "

Ingot - Steel cast in a metal mold ready for rolling or forging. It is distinct from a casting, which is not rolled or forged. Ingots are usually rectangular, called slabs; square, called blooms; polygonal, eight- or 12-sided for forging. Squares and polygonal ingots can be fluted or corrugated to increase the surface area and reduce the tendency to crack while cooling.

Ingot Iron - Iron of comparatively high purity produced in open-hearth furnace under conditions that keep down the carbon, manganese, and silicon content; e.g., Armco Iron

Ingot Mould - The receptacle into which molten steel is poured to form an ingot. After solidification the steel is suitable for subsequent working, i.e. rolling or forging.

Inhibitor - A substance which retards some specific chemical reaction. Pickling inhibitors retard the sissolution of metal without hindering the removal of scale from steel.

Injection Molding - The injection of molten metal or other material under pressure into molds.

Injection Water - Automatically regulated water that provides a seal in the circulator pumps. The injection water is supplied from the boiler feed water header.

Inlet - Entry valve to auto valve or tank.

Inmetco - Coal-based process similar to FASTMET that uses iron oxide fines and pulverized coal to produce a scrap substitute. Mill scale and flue dust, inexpensive byproducts of steelmaking, can be mixed with the iron oxide fines. Inmetco, unlike other direct reduction products, is intended to be hot charged into an EAF, with attendant energy savings. The process includes three steps. First, iron oxide fines, pulverized coal and a binder are formed into pellets. Second, the pellets, two to three layers deep, are heated in a gas-fired rotary hearth furnace for 15-20 minutes to produce sponge iron. Subsequently, the iron must be desulfurized. The coal in the pellets provides much of the energy required in the second phase.

Inoculant - Material which when added to molten metal modifies the structure, and thereby changes the physical and mechanical properties to a degree not explained on the basis of the change in composition resulting from its use.

Inoculation - "Addition to molten metal of substances designed to form nuclei for crystallization. Also see Inoculant "

Insert - A part usually formed from metal, which is placed in a mold and may become an integral part of the casting.

Inserted-Tooth Cutter - A milling cutter designed with replaceable cutting tooth inserts to save the expense of a new cutter whenever the teeth become damaged or worn. Generally, they are made 6 inches or more in diameter.

Inspection lot - See lot, inspection

Insulating Pads and Sleeves - As opposed to chills, insulating material, such as gypsum, diatomaceous earth, etc., used to lower the rate of solidification. As sleeves on open risers, they are used to keep the metal liquid, thus increasing the feed efficiency.

Integral Dose (Volume Dose) - A measure of the total energy absorbed by man or any object during exposure to radiation.

Integrated Manufacturing Information System - (IMIS) Computer system used to record production information.

Integrated Mills - These facilities make steel by processing iron ore and other raw materials in blast furnaces. Technically, only the hot end differentiates integrated mills from mini-mills. However, the differing technological approaches to molten steel imply different scale efficiencies and, therefore, separate management styles, labor relations and product markets. Nearly all domestic integrated mills specialize in flat-rolled steel or plate.

Integrated Plant - A mill that produces steel from basic raw materials from the ore pile to a finished product.

Integrated Steel Producer - A steel company which manufactures solid steel products; starts with raw materials such as iron ore, flux, etc, to make molten iron; converts the molten iron to liquid steel in the steelmaking furnaces and processes liquid to solid steel products. See Minimill Steel Producer.

Intensity (Radiology) - Amount of energy per unit time passing through a unit area perpendicular to the line of propagation at the point in question. Often this term is used incorrectly in the sense of dose rate.

Inter-Chemical Gauge - Wet film thickness can also be measured using an Inter-chemical Gauge. A graduated circular cam is rolled against the plate between two parallel rollers. The wet film thickness is then read directly on cam at demarcation of coating wetting the cam.

Intercast Process - A patented procedure for die casting " cast-assemble " units with moving parts.

Intercrystalline - Between crystals, or between grains. Same as intergranular.

Intercrystalline Corrosion - Chromium-nickel austenitic stainless steels are prone to this form of corrosion when they are welded and subsequently in contact with certain types of corrosive media. When heated within a temperature range of 450-800oC precipitation of the chromium carbides takes place at the grain boundries in the area of the weld and these areas not longer have the protection of the chromium on the peripneries of the grains. This type of corrosion is also known as Weld Decay and Intergranular Corrosion. The most common way to avoid the problem is to select a grade of steel that is very low in carbon i.e. 0.03% or less, or one that is stabilzed with niobium or titanium.

Intercrystalline Failure - Cracks or fractures that follow along the grain boundaries in the microstructure of metals and alloys.

Interdendritic Attack - A type of electrochemical corrosion that sometimes occurs in as-cast alloys or alloys that have had very little working.

Intergranular Corrosion - Corrosion in a metal taking place preferentially along the grain boundaries.

Intermediate Gear - See Idler

Intermediate Temper - A cold rolled hardness range specified with a 15-point Rockwell B spread. See Quarter Hard Temper and Half-Hard Temper.

Internal Cleanliness - Measure of number and types of non-metallic inclusions such as oxides, sulfides or silicates.

Internal Friction - Ability of a metal to transform vibratory energy into heat; generally refers to low stress levels of vibration; damping has a broader connotation since it may refer to stresses approaching or exceeding yield strength.

Internal Shrinkage - A void or network of voids within a casting caused by inadequate feeding of that section during solidification.

Internal Stresses (or Thermal Stresses) - Generally stresses which occur during the cooling of a part.

Interrupted Aging - The aging of an alloy at two or more temperatures by steps, and cooling to room termperature after each step. Compare with progressuve aging.

Interrupted Quench - Removing the casting from a quenching bath before it has reached the temperature of the bath.

Interstitial Free Steel - A recently developed sheet steel product with very low carbon levels that is used primarily in automotive deep-drawing applications. Interstitial Free Steel's improved ductility (drawing ability) is made possible by vacuum degassing.

Intracrystalline - Within or across crystals or grains. Same as transcrystalline and transgranular.

Invar - An alloy having practically no expansion when heated; 36% Ni, 0.5% Mn, 0.2% C, and the balance Fe.

Inverse Chill - The condition in a casting section where tht einterior is molttled or white, while the other sections are gray iron. Also known as Reverse Chill, Internal Chill and Inverted Chill.

Inverse Segregation - "A concentration of certain alloy constituents that have lower melting points in the region corresponding to that first solidifying; caused by interdendritic flow of enriched liquid through channels where the pressure drops with contraction of dendrites. The internal evolution of hydrogen may also give a positive pressure, aiding this flow and causing a liquidated surface as tin sweat. See also Segregation "

Inversion - A change in crystal form without change in chemical composition, as from quartz to cristobalite.

Inversion Casting - 1) The metal is fed through a bottom feeder, the mold being inverted for pouring, 2) the mold is directly attached to the electric furnace in which the metal is melted in a reducing atmosphere so no slag is formed. On inverting the furnace the metal runs into the mold. There are no heavy feeders and oxidation is prevented.

Investing - The process of pouring the investment slurry into the flask surrounding the pattern to form the mold.

Investment - A flowable mixture of a graded refractory filler, a binder and a liquid vehicle which when poured around the patterns conforms to their shape and subsequently set hard to form the investment mold.

Investment Casting - Casting produced in a mold obtained by investing an expendable pattern with a refractory to produce a shell. The expendable pattern may consist of wax, plastic, or other material and is removed prior to filling the mold with liquid metal.

Investment Precoat - "An extremely fine investment coating applied as a thin slurry directly to the surface of the pattern to reproduce maximum surface smoothness. The coating is surrounded by a coarser, cheaper, and permeable investment to form the mold. See Dip Coat "

Inwall Brick - Refractory lining of the inwall section of blast furnace or cupola.

Ionization - The process or the result of any process by which a neutral atom or molecule acquires either a positive or a negative charge.

Ionization Chamber - An instrument designed to measure quantity of ionizing radiation in terms of the charge of electricity associated with ions produced within a defined volume.

IPM - An identifiable piece of steel; can be a slab, coil, or a bundle of sheets, or several slit mults banded together.

IPM Number - (In-Process Material) A seven-character number, consisting of the unit ID and sequential production number, used to track production history of a coil. The letter and first digit are used to identify the production unit and the last five digits are the sequential production identifying number.

Iridium - A noble metal of the platinum group. Usually extensively as a radiation source. For radiography of thin walled castings.

Iron - 1) A metallic element, mp 1535 C (2795 F), 2) irons not falling into the steel categories, as Gray Iron, Ductile Iron, Malleable Iron, White Iron, Ingot, and Wrought Iron.

Iron-Based Superalloys - Also known as super chrome steels, these metals are at the highest end of the range of high-temperature,high-strength steels. Besides chrome,other additives can be nickel, titanium, manganese, molybdenum, vanadium, silicon, and carbon.

Iron Carbide - One of several substitutes for high-quality, low-residual scrap for use in electric furnace steelmaking. Iron carbide producers use natural gas to reduce iron ore to iron carbide.

Iron Ore - Mineral containing enough iron to be a commercially viable source of the element for use in steelmaking. Except for fragments of meteorites found on Earth, iron is not a free element; instead, it is trapped in the earth's crust in its oxidized form.

Iron Oxide - This material as prepared for foundry use generally contains about 85% ferric oxide and is produced by pulverizing a high grade of pure iron ore. It can be added to core sand mixes to assist in keeping the core from cracking before the metal solidifies during the casting operation and also helps to resist metal penetration during this period. Added to molding sand mixtures for control of finning and veining. Also may reduce carbon pick up.

Iron Sand - See Iserine

Iron, Hard or White - Irons (Fe3C) possessing white fracture because all or substantially all of the carbon is in the combined form. Irons to be malleablized are cast white, as are many abrasion-resistant irons.

Iron, Malleable - A mixture of iron and carbon, including smaller amounts of silicon, manganese, phosphorus, and sulfur, which after being cast (white iron, carbon in combined form as carbides) is converted structurally by heat treatment into a matrix of ferrite containing nodules of temper carbon (graphite).

Iron, Pearlitic Malleable - A malleable iron having a more or less pearlitic matrix.

Iron-Carbon (Graphite) Diagram - A diagram representing stable equilibrium conditions between iron and graphite (pure carbon) phase over the entire range of iron and steel.

Iron-Iron Carbide Diagram - A phase diagram representing metastable equilibrium conditions between Fe and Fe3C over the entire range of carbon steels and cast irons.

Iron-Zinc Alloy Coating - See Galvanized.

Iserine - A black sand which consists mainly of magnetic iron ore but also contains a considerable amount of titanium.

ISO - International Standards Organization.

Isocure - Proprietary name for a binder system developed for use in Ashland (Cold Box) Process, itself a proprietary process.

Isocyanate Acid - Isomeric cyanic acid (HNCO).

Isolate - (Isolation) To remove a boiler, or any particular part or system of a boiler, form service by closing the manual valves.

Isolation - The process of de-energizing, line-blanking, bleeding, and locking, tagging and trying to secure a system or piece of equipment for work.

Isomorphous - Phases with crystal structures of the same type.

Isothermal - Pertaining to changes or other phenomena occurring at a constant temperature.

Isothermal Transformation - 1) The process of transforming Austenite in a ferrous ally to Ferrite or a ferrite-carbide aggregate at any constant temperature within the transformation range, 2) transformation of one phase in an alloy system to another phase at any constant temperature.

Isothernal Transformation Curve - Also known as the Time Temperature Transformation Curve. If a small piece of steel is heated sufficiently slowly for it to become austenitic and then plunged into a salt bath and held at a constant temperature below the upper critical point for a definite time followed by rapid quenching, it is possible by examination to determine the extent to which the transformation of the austentite has occurred. By taking anumbet of speciments of the same steel and treating them in the same way, but varying the holding temperature and time behavior of the steel with time and temperature can be studied. The information obtained can be plotted as time-temperature transformation curves which is useful in heat treatment practice, particularly for martempering and austempering.

Isotope - One of several different nuclides having the same number of protons in their nuclei, and hence having the same atomic number, but differing in the number of neutrons and therefore in the mass number.

Izod Impact Test - A test specimen, usually of squaare crossed section is notched and held between a pair of jaws, to be broken by a swinging or falling weight. When the pendulum of the Izod testing machine is released it wsings with a downward movement and when it reaches the vertical, the hammer makes contact with the specimen which is broken by the force of the blow. The hammer continues its upward motion by the energy absorbed in breaking the test piece reduces its momentum. A graduated scale enables a reading to be taken of the energy used to fracture the test piece. To obtain a representative result the average of three tests is used and to ensure that the results conform to those of the steel specification the test specimens should meet the standard dimesions laid down in BS 131.

Idiomorph - A particle of a phase the has a regular external shape.

Impact Energy (Impact Value) - The amount of energy required to ffracture a material, usually measured by means of an Izod or Charpy test. The type of speciment and testing conditions affect the values and therfore should be specified.

Impact Test - Test designed to determine the resistance of metal to breakage by impact, usually by concentrating the applied stress to a notched specimen.

Impact Test - A test to determine the behavior of materials when subjected to high rates of loading,usually in bending, tension, or torsion. The quantity measured is the energy absorbed in breaking the specimen by a single blow, as in the Charpy or Izod.

Impact Test - A test for determining the behaviour of materials when subjected to high rates of loading under conditions designed to promote fracture, usually in bending, tension or torsion. The quantity measured is the energy absorbed when the specimen is broken by a single blow.

Impurities - Elements or compounds whose presence in a material is undesired.

Inclusion - A nonmetallic material in a solid metallic matrix.

Inclusions - Non,etallic materials in a solid metallic matrix.

Indentation Hardness - The resistance of a meterial to indentation. This is the usual type osf hardness test, in which a pointed or rounded indenter is pressed into a surface under a substantially static load.

Induction Hardening - Quench hardening in which the heat is generated by electrical induction.

Induction Hardening - A process of hardening a ferrous alloy by heating it above the transformation range by means of electrical induction, and then cooling as required.

Induction Heating - A process of heating by electrical induction.

Inert-Gas Shielded-Arc Welding - Arc welding in an inert gas such as argon or helium.

Ingot - A casting suitable for hot working or remelting.

Ingot - A casting for subsequent rolling or forging.

Ingot Iron - Commercially pure iron.

Ingot Iron - Commercially pure open-hearth iron.

Interleaving - The placing of a sheet of paper between two adjacent layers of metal to facilitate handling and shearing of rectangular sheets, or to prevent sticking or scratching.

Intermediate Annealing - An annealing treatment given to wrought metals following cold work hardening for the purpose of softening prior to further cold working.

Internal Oxidation - Formation of oxides beneath the surface of a metal.

Interrupted Quenching - Quenching in which the metal object being quenched is removed from the quenching medium while the object is at a temperature substantially higher than that of the quenching medium.

Interstitial Solid Solution - A solid solution in which the solute atoms occupy (interstitial) positions between the atoms in the structure of the solvent.

Investment Casting - (1) Casting metal into a mold produced by surrounding (investing) an expendable pattern with a refractory slurry that sets at room temperature after which the wax, plastic, or frozed mercury pattern is removed through the use of heat. Also called precision casting, or lost-wax process. (2) A casting made by the process.

Irom - (Chemical symbol Fe.) Element No. 26 of the periodic system; Atomic weight 55.85. A magnetic silver white metal of high tensile strength, ductile and malleable. Melting point of pure iron about 2795 (degrees) F. Chemically iron is chiefly base forming. The principal forms of commercial iron are steel, cast iron and wrought iron.

Iron - An element that has an average atomic number of 55.85 and that always, in engineering practice, contains small but significant amounts of carbon. Thus iron-carbon alloys containing less than about 0.1% C may be referred to as irons. Alloys with higher carbon contents are always termed steels.

Ironing - Thinning the walls of deep drawn articles by reducing the clearance between punch and die.

Isothermal Annealing - A process in which a ferrous alloy is heated to produce a structure partly or wholly austenitic, and is then cooled to and held at a temperaure that causes transformation of the austenite to a relatively soft ferrite-carbide aggregate.

Isothermal Transformation - A change in phase at any constant temperature.

Isothermal Transformation (IT) Diagram - A diagram that shows the isothermal time required for transformation of austenite to commence and to finish as a function of temperature. Same as time-temperature-transformation (TTT) diagram or S-curve.

Izod Test - A pendulum type of single-blow impact test in which the specimen, usually notched, is fixed at one end and broken by a falling pendulum. The energy absorbed, as measured by the subsequent rise of the pendulum, is a measure of impact strength or notch toughness.