Nailing
Slow heating to visible redness of refractory crucibles prior to use of crucibles for the melting of steel.
Natural Gas
Derived from the remains of marine animal and plant life (same as petroleum), natural gas is made up predominantly of hydrocarbons. Petroleum rarely is free of natural gas and the same fields usually produce both fuels. Gas found in a field is usually under pressure which diminishes with extended use or from the presence of too many other wells.
Necking
Strip condition caused by the application of too much tension which causes the strip to become narrower (or stretched) before fracture.
Neutral Refractory
A refractory having neither strongly acidic nor basic properties, for example, chromite.
NDT
Non-destructive testing, mainly used in pipe mills.
Nickel (Ni)
An alloying element used as a raw material for certain classes of stainless steel. Nickel provides high degrees of ductility (ability to change shape without fracture) as well as resistance to corrosion. Approximately 65% of all nickel is used in the making of stainless steel.
Nitriding
The nitrogen case-hardening process which consists of subjecting machined and heat-treated parts to the action of a nitrogenous medium, commonly ammonia gas, at temperatures of about 510o to 538o. The outer layer of a conventionally nitrided case contains a shallow (0.05mm) but very brittle ‘white layer’ consisting or iron and other nitrides. Quenching is not required to produce a hard case.
Nitrocarburizing
Any of several case-hardening processes in which nitrogen and carbon are absorbed into the surface layers of a ferrous material at temperatures below the lower critical temperature and, by diffusion, create a concentration gradient. Compare with carbonitriding.
No. 1 Heavy Melt
Obsolete steel scrap grade, at least one-quarter inch in thickness and in sections no larger than five feet by two feet. Much of the metal comes from demolished buildings, truck frames and heavy duty springs. Mini-mills are primary consumers of No. 1 heavy scrap.
Non-Aging
Little to no change in mechanical and physical properties over time; Yield point elongation is zero. See Aging.
Normalizing
Heating to a temperature about 100o F above the critical range, as indicated by the iron carbon diagram, and cooling in still air. Normalizing is used to restore the steel to its normal condition after hot working, cold working, non-uniform cooling or overheating, or to eliminate the effects of previous heat treatment. Other common objects of normalizing include the development of uniformity in grain, structure and physical properties, a slight hardening of medium carbon steels to improve machinability and the removal of stresses, strains, or course grain prior to hardening. The usual normalizing temperatures range from about 1500o degrees to 1800o F depending on the steel involved.
Non-Temper Passed Bands
Hot bands.
Nozzle
The refractory lined outlet tube, generally between 25 to 50 mm in diameter, through which molten steel is released from the ladle to fill up moulds.
OCTG
See Oil Country Tubular Goods.
OD
Outside diameter (of a coil).
Off Gauge
A defect referring to a variation of offset of the thickness of the plate from the designated aim gauge thickness and tolerance.
Offsetting
A coating defect consisting of a transference of smearing of ink or coating or other substance from the surface of one sheet of coated substrate to the back of the next sheet in a stack.
Oil Country Tubular Goods (OCTG)
Label applied to the pipe products used by petroleum exploration customers. Includes casing, drill pipe and oil well tubing, which, depending on their use, may be formed through welded or seamless processes.
Oiled
A product to which oil has been applied to retard rusting.
Oil Film Weight
Measure of the amount of oil applied to a flat rolled steel product; for Tin Mill Products, the measure is grams/base box; for Sheet Products, the measure is oz./sq.ft. (or gm./sq.m.).
Oiling
The application of a surface layer of lubricant intended to retard rusting on sheet products and lubrication on Tin Mill products.
Olsen Cup Test
A test used to obtain an indication of the drawing properties of the base metal as well as the adherence of the coating. In this test, the male and female dies are used to deform the steel into a cup shape. The force draws the metal into the die slowly so the coated sheet stretches to conform to the shape of the die. The depth of the cup is measured when the steel fractures, and the coating is then examined.
Open Coil Annealing (Unitised Annealing)
Annealing of a sheet coil in the form of a loosely wound coil with or without a metal spacer between successive laps of the coil, thus providing gap for the atmosphere to circulate around each lap of the coil. This form of annealing is generally used for decarburisation annealing and / or nitriding, that is, annealing simultaneously with decarburisation and denitriding to produce extra low carbon and low nitrogen steels. Generally it is carried out in Bell type furnaces, but when carried out in Bogie Hearth Furnaces, the process is usually termed as ‘unitised annealing’.
Open Hearth Furnace
A broad, dish-shaped, shallow hearth to refine pig iron and scrap into steel. Heat is supplied through convection from a large, luminous flame over the surface of the metal and by radiation from the roof, and the refining takes seven to nine hours. Open Hearths, at one time the most abundant steel making furnaces among integrated companies, have been replaced by the basic oxygen furnace.
Open Line
Usually a steel-making defect, an open line refers to a line down the length of the strip caused by unknown conditions.
Open Steel
Steel partially killed prior to casting.
Open Weld
A weld that shows an area which is not fused.
Operating Rates
The ratio of raw steel production to the mill’s stated capacity.
Orange Peel
Characteristic roughing over the surface of cold-rolled or cold-deformed sheet or strip due to coarse grain size. Also known as pebbles and alligator skin
Order Rate
The ratio of new orders recorded to the mill’s capacity to produce the steel to fill the orders. Many analysts view trends in the order rate as harbingers of future production levels.
Ore
An iron bearing material used primarily in the blast furnace.
Organosol
Organosols contain poly-vinyl chloride (PVC) dispersed in solvents. At temperatures of 325-350o F (165-175o C) the vinyl particles coalesce and dissolve in the plasticizers to form homogeneous films with good hardness, toughness and adhesion.
Oscillating
A method of winding narrow strip steel over a much wider roll. Customers want to have as much steel on a coil as will fit in their machines, so they can spend less time moving the material and more time using it. By coiling the strip like fishing line (or thread) over a spool, a much longer strip can fit onto a coil of proper diameter. Oscillate-wound coils allow the customer to enjoy longer processing runs.
Overaging
Aging under conditions of time and temperature greater than those required to obtain maximum change in a certain property. See also aging.
Overheating
Heating to such a high temperature that an undesirably coarse grained structure is produced. Severe overheating may result in the properties being permanently impaired.
Overpickling
Results from line delays which permit sections of the steel to remain in the acid too long. Causes pronounced chemical attack, resulting in pitting and roughness on the surface.
Overwidth
Product whose width is above the customer’s finished width tolerance.
Oxidation
Rust, corrosion. See Red Rust and White Rust.
Oxygen Enrichment (of Blast)
Enrichment of blast air with oxygen to increase hot metal production in the blast furnace. For every percent of oxygen above the normal air blast (21%), the production rate can be increased about 2 to 4%.
Oxygen Lance
Pure oxygen is injected into the molten steel during top-blown oxygen steel-making process through a tubular, water-cooled, copper-tipped retractable lance kept perpendicular above the center of the bath. At the top of the lance, armored rubber hoses are connected to a pressure-regulated oxygen source and top a supply of re-circulated cooling water. The tip of the lance contains from three to five converging-diverging nozzles to impart a supersonic velocity (mach 1.7 to 2.3) to the gas jets exiting normally under a pressure between 140 to 180 psi.
Pack Carburizing
The steel is packed in boxes with carbonaceous solids, sealed to exclude the atmosphere, and heated to about 927oC for a period of time depending upon the depth of case desired. A time of about 8 hours at 927oC results in a case depth of about 1.6mm.
Pack Carburizing
The steel is packed in boxes with carbonaceous solids, sealed to exclude the atmosphere, and heated to about 927oC for a period of time depending upon the depth of case desired. A time of about 8 hours at 927oC results in a case depth of about 1.6mm.
Pack Rolling
Rolling two or more sheets at a time, in one pack.
Pairs
Two sheets hot-rolled together.
Paper Drum
Paper insert placed on the reel around which the coil is wound. The drum is used to eliminate damage in the center of the coil. Certain customers may require that coils are to be shipped with this paper drum.
Passivated Tin Plate
Tin plate that has been chemically treated to control tin oxide formation and growth.
Passivation Treatment
See Chemical Treatment.
Parting Line (Die line)
The dividing plane between the faces of a pair of dies.
Peg (Stopper)
A block placed to keep the forging tools at a minimum distance.
Peeling
Separation of the zinc coating from the steel strip.
Pellets
(See Agglomerating Process.)
Peritectic Grade
Crack sensitive grade of steel with .08 to .16% Carbon.
Phenolic
A type of resin made from a condensation reaction of phenols and aldehydes. Resultant films have a high degree of chemical resistance with limited flexibility properties.
Phosphatized
See Bonderized Coating.
Phosphide Streak
An elongated area of segregated phosphide which revealed on etching.
Pickler
- An operating unit that removes iron oxide from a hot rolled product by immersion into a hydrochloric or sulfuric acid solution. 2. The pickler tank contains 5-6% concentrations of sulfuric acid. This solution is kept at a temperature of 180-190o F. The purpose of the pickler is to complete the preparation of the steel for plating, by removing any oxides from the surface.
Piano Wire (Music Wire)
A very high quality high carbon, patented drawn and polished wire having a tensile strength in excess of 190 kgf/mm2 and generally in size of 1.6 mm dia and finer. The term music wire also includes wire intended for mandolins.
Pickle Stain
Surface stain after pickling due to inadequate washing and drying
Pickling
What Process that cleans a steel coil of its rust, dirt and oil so that further work can be done to the metal.
Why When hot-rolled coils cool, rust forms on the unprotected metal; often coils are stored or transported while exposed to outside air and water.
How Through a continuous chemical or electrochemical process, the steel is uncoiled and sent through a series of hydrochloric acid baths that remove the oxides (rust). The steel sheet is then rinsed and dried.
Piercing
Making a hole with a tapered and pointed tool without removal of metal.
Pigging Back
Introduction of carbon in the steel bath by the addition of pig iron.
Pig Iron
The name for the melted iron produced in a blast furnace, containing a large quantity of carbon (above 1.5%, usually between 3% to 4.5%), along with silicon, manganese, phosphorus, and sulphur in varying amounts depending upon the quality of raw materials used and solidified in moving metal moulds of a Pig Casting Machine. Pig iron is used in the foundry or for conversion into steel. Named long ago when molten iron was poured through a trench in the ground to flow into shallow earthen holes, the arrangement looked like newborn pigs suckling. The central channel became known as the “sow,” and the moulds were “pigs.”
Piling (Sheet Piling)
A structural steel product with edges designed to interlock; used in the construction of cofferdams or riverbank reinforcement.
Pipe
- Technically a tube used to transport fluids or gases. However, pipe and tube are often used interchangeably in steel lexicon, with a given label applied primarily as a matter of historical use.
- An axial cavity caused by contraction during solidification of an ingot. Also the defects arising from the axial cavity on the semi-finished or finished products.
Pinchers
Surface disturbances which result from the rolling process and which ordinarily appear as fernlike ripples running diagonally across the direction of rolling.
Pinch Rolls
While preparing the coils for processing, the lead edge of the strip is manually engaged in a set of small pinch rolls which can be opened and closed by air pressure and which are usually motor driven. The function of these rolls is to permit the operator to advance the lead edge of a new coil into the welding assembly.
Pin-hole Detector
Device based on photoelectric cell which continuously scan, identify and tabulate the number of pin holes in a coil.
Pinholes
A coating defect consisting of the randomly spaced small round holes (as a straight pin would make in the cured film, which quite often occur in large numbers. The open area (pinhole) usually exposes bare substrate. Contaminated substrate or improperly dispersed lubricant or additive may cause pinholes. Pinholes are typically caused by laminations, inclusions, scratches or gouges.
Pipe (Contraction Cavity, Shrinkage Cavity)
An axial cavity caused by contraction during solidification of an ingot. Also the defect arising from the axial cavity in semi-finished or finished products.
Pit Sample (Ladle Sample)
The sample taken from a cast during teeming into moulds, for determining the chemical composition of the cast.
Pitting
A coating defect consisting of randomly spaced small depressions in the cured film. Pitting is similar to pinholing, except that pits do not expose the bare substrate.
Planishing
Improving the surface by the action of chill cast or hardened steel rolls or by hammering with smooth faced hammer.
Plastic Deformation
Permanent deformation occurring in forming of metal which occurs after elastic limits have been exceeded.
Plasticity
The property that enables a material to undergo plastic deformation without rupture.
Plastic Working
The permanent deformation accomplished by applying mechanical forces to a metal surface. The primary objective of such working is usually the production of a specific shape or / and size or the improvement of certain physical properties of the metal.
Plate
A hot or cold rolled flat product, rolled from an ingot or slab in rectangular cross section with a width 600mm and above and a thickness 5mm and above (going upto one foot). (See Sheet Steel).
Plater
An operating unit which electrolytically applies zinc, chrome or tin to black plate.
Plugged Steel
It is a rimming steel poured in a bottle shaped mould with a central plug. The rimming action is arrested when the metal rises and comes in contact with the bottle portion of the mould and the central plug.
Plumbago
A material with graphite as the primary constituent, used for its refractoriness.
Plowing
In tribology, the formation of grooves by plastic deformation of the softer of two surfaces in relative motion.
Polishing
A mechanical, chemical, or electrolytic process or combination thereof used to prepare a smooth, reflective surface suitable for micro-structural examination that is free of artifacts or damage introduced during prior sectioning or grinding.
Porter Bar
The tool used to hold the ingot or bloom during forging.
Post-Paint
To paint a manufactured part after it has been formed.
Powdering
A problem encountered in the field where the iron-zinc coating (from Galvanneal products) comes off the base metal and collects in the die.
Powder Injection
Powdered desulphurizing materials such as magnesium-flourspar (Mag-Spar), calcium silicide (Cal-Sil) or prefused calcium aluminate, are injected with a single or a double-port lance deep into the steel bath in the ladle with argon flowing at rates in the range 0.9-1.8 nm3/min for ladle refining of steel.
Powdered Iron
The sponge iron in the purified granular form. It is used in the manufacture of many useful articles articles by the metallurgy where (1) iron powders are first compacted by pressure alone into the approximate shape of the finished article; (2) the compact is then ‘sintered’ at a temperature ranging between approximately 950 and 1095o C in furnaces provided with a protective atmosphere to prevent oxidation; and (3) the sintered articles are then pressed or machined to their final shape.
Powder Metals
Fabrication technology in which fine metallic powder is compacted under high pressure and then heated at a temperature slightly below the melting point to solidify the material. Primary users of powder metal parts are auto, electronics and aerospace industries.
Precipitation Hardening (PH)
Hardening due to the precipitation of a constituent from a super-saturated solid solution upon quenching and then holding at a prescribed temperature below transformational range. A small group of stainless steels with high chromium and nickel content, with the most common types having characteristics close to those of martensitic (plain chromium stainless class with exceptional strength) steels. Heat treatment provides this class with its very high strength and hardness. Applications for PH stainless steels include shafts for pumps and valves as well as aircraft parts.
Pre-Paint
To paint a product in coil form and then manufacture it into a final part.
Press Forming
See Brake Press Bending.
Pretreated
Steel to which a chemical treatment has been applied to prepare it for future surface treatments such as painting. (See Bonderized, Light Special Treatment and Special Treatment).
Prime Coil
Any coil produced by the line that is not held for any out-of-spec or quality reasons.
Process Annealing
A heat treatment used to soften metal for further cold working. In ferrous sheet and wire industries, heating to a temperature close to but below the lower limit of the transformation range and subsequent cooling for working. In the non-ferrous industries, heating above the recrystalization temperatures at a time and temperature sufficient to permit the desired subsequent cold working.
Process Control System
The general form of a process control system is one in which a multiplicity of inputs, such as the physical and chemical characteristics of the raw materials, the energy levels, the machine settings, and so forth are used to provide desired outputs such as product quality, productivity, and minimum cost, or some selected combination of these. In addition, there may be other outputs required; for example, processing information for supporting functions such as accounting and evaluation.
Producer Gas
Producer gas is manufactured by blowing an insufficient supply of air for complete combustion, with or without the admixture of steam, through a thick, hot, sold-fuel bed. A large proportion of the original heating value of the solid fuel is recovered in the potential heat of carbon monoxide, hydrogen, tarry vapours, and some hydrocarbons, and in the sensible heat of the composite gas which also contains carbon dioxide and nitrogen.
Progressive Aging
Aging by increasing the temperature in steps or continuously during the aging cycle. Compare with interrupted aging and step aging.
Prompt Industrial Scrap
The scrap generated by steel consumers in making their products. It may consist of the unwanted portions of plate or sheet that has been cut or sheared to the desired final size and shape, trimmings resulting from stamping and pressing operations, machine turnings, rejected products scrapped during manufacture, short ends, flash from forgings, and other types of scrap.
Puddling Furnace
The process used for the production of wrought iron, pig iron and cast iron by means of chemical action. This process was invented in 1780. The older process, dry puddling, is known as Cort’s Process and the newer, wet puddling or pig boiling, is known as Hall’s Process.
Pull
An irregular transverse crack on the face of an ingot caused by restriction to free contraction during cooling in the mould.
Pulverized Coal Injection System (PCI)
A blast furnace enhancement to reduce an integrated mill’s reliance on coke (because of environmental problems with its production). Up to 30% of the coke charged into the blast furnace can be replaced by this talcum-like coal powder, which is injected through nozzles at the bottom of the furnace.
Rolling two or more sheets at a time, in one pack.
Pairs
Two sheets hot-rolled together.
Paper Drum
Paper insert placed on the reel around which the coil is wound. The drum is used to eliminate damage in the center of the coil. Certain customers may require that coils are to be shipped with this paper drum.
Passivated Tin Plate
Tin plate that has been chemically treated to control tin oxide formation and growth.
Passivation Treatment
See Chemical Treatment.
Parting Line (Die line)
The dividing plane between the faces of a pair of dies.
Peg (Stopper)
A block placed to keep the forging tools at a minimum distance.
Peeling
Separation of the zinc coating from the steel strip.
Pellets
(See Agglomerating Process.)
Peritectic Grade
Crack sensitive grade of steel with .08 to .16% Carbon.
Phenolic
A type of resin made from a condensation reaction of phenols and aldehydes. Resultant films have a high degree of chemical resistance with limited flexibility properties.
Phosphatized
See Bonderized Coating.
Phosphide Streak
An elongated area of segregated phosphide which revealed on etching.
Pickler
- An operating unit that removes iron oxide from a hot rolled product by immersion into a hydrochloric or sulfuric acid solution. 2. The pickler tank contains 5-6% concentrations of sulfuric acid. This solution is kept at a temperature of 180-190o F. The purpose of the pickler is to complete the preparation of the steel for plating, by removing any oxides from the surface.
Piano Wire (Music Wire)
A very high quality high carbon, patented drawn and polished wire having a tensile strength in excess of 190 kgf/mm2 and generally in size of 1.6 mm dia and finer. The term music wire also includes wire intended for mandolins.
Pickle Stain
Surface stain after pickling due to inadequate washing and drying
Pickling
What Process that cleans a steel coil of its rust, dirt and oil so that further work can be done to the metal.
Why When hot-rolled coils cool, rust forms on the unprotected metal; often coils are stored or transported while exposed to outside air and water.
How Through a continuous chemical or electrochemical process, the steel is uncoiled and sent through a series of hydrochloric acid baths that remove the oxides (rust). The steel sheet is then rinsed and dried.
Piercing
Making a hole with a tapered and pointed tool without removal of metal.
Pigging Back
Introduction of carbon in the steel bath by the addition of pig iron.
Pig Iron
The name for the melted iron produced in a blast furnace, containing a large quantity of carbon (above 1.5%, usually between 3% to 4.5%), along with silicon, manganese, phosphorus, and sulphur in varying amounts depending upon the quality of raw materials used and solidified in moving metal moulds of a Pig Casting Machine. Pig iron is used in the foundry or for conversion into steel. Named long ago when molten iron was poured through a trench in the ground to flow into shallow earthen holes, the arrangement looked like newborn pigs suckling. The central channel became known as the “sow,” and the moulds were “pigs.”
Piling (Sheet Piling)
A structural steel product with edges designed to interlock; used in the construction of cofferdams or riverbank reinforcement.
Pipe
- Technically a tube used to transport fluids or gases. However, pipe and tube are often used interchangeably in steel lexicon, with a given label applied primarily as a matter of historical use.
- An axial cavity caused by contraction during solidification of an ingot. Also the defects arising from the axial cavity on the semi-finished or finished products.
Pinchers
Surface disturbances which result from the rolling process and which ordinarily appear as fernlike ripples running diagonally across the direction of rolling.
Pinch Rolls
While preparing the coils for processing, the lead edge of the strip is manually engaged in a set of small pinch rolls which can be opened and closed by air pressure and which are usually motor driven. The function of these rolls is to permit the operator to advance the lead edge of a new coil into the welding assembly.
Pin-hole Detector
Device based on photoelectric cell which continuously scan, identify and tabulate the number of pin holes in a coil.
Pinholes
A coating defect consisting of the randomly spaced small round holes (as a straight pin would make in the cured film, which quite often occur in large numbers. The open area (pinhole) usually exposes bare substrate. Contaminated substrate or improperly dispersed lubricant or additive may cause pinholes. Pinholes are typically caused by laminations, inclusions, scratches or gouges.
Pipe (Contraction Cavity, Shrinkage Cavity)
An axial cavity caused by contraction during solidification of an ingot. Also the defect arising from the axial cavity in semi-finished or finished products.
Pit Sample (Ladle Sample)
The sample taken from a cast during teeming into moulds, for determining the chemical composition of the cast.
Pitting
A coating defect consisting of randomly spaced small depressions in the cured film. Pitting is similar to pinholing, except that pits do not expose the bare substrate.
Planishing
Improving the surface by the action of chill cast or hardened steel rolls or by hammering with smooth faced hammer.
Plastic Deformation
Permanent deformation occurring in forming of metal which occurs after elastic limits have been exceeded.
Plasticity
The property that enables a material to undergo plastic deformation without rupture.
Plastic Working
The permanent deformation accomplished by applying mechanical forces to a metal surface. The primary objective of such working is usually the production of a specific shape or / and size or the improvement of certain physical properties of the metal.
Plate
A hot or cold rolled flat product, rolled from an ingot or slab in rectangular cross section with a width 600mm and above and a thickness 5mm and above (going upto one foot). (See Sheet Steel).
Plater
An operating unit which electrolytically applies zinc, chrome or tin to black plate.
Plugged Steel
It is a rimming steel poured in a bottle shaped mould with a central plug. The rimming action is arrested when the metal rises and comes in contact with the bottle portion of the mould and the central plug.
Plumbago
A material with graphite as the primary constituent, used for its refractoriness.
Plowing
In tribology, the formation of grooves by plastic deformation of the softer of two surfaces in relative motion.
Polishing
A mechanical, chemical, or electrolytic process or combination thereof used to prepare a smooth, reflective surface suitable for micro-structural examination that is free of artifacts or damage introduced during prior sectioning or grinding.
Porter Bar
The tool used to hold the ingot or bloom during forging.
Post-Paint
To paint a manufactured part after it has been formed.
Powdering
A problem encountered in the field where the iron-zinc coating (from Galvanneal products) comes off the base metal and collects in the die.
Powder Injection
Powdered desulphurizing materials such as magnesium-flourspar (Mag-Spar), calcium silicide (Cal-Sil) or prefused calcium aluminate, are injected with a single or a double-port lance deep into the steel bath in the ladle with argon flowing at rates in the range 0.9-1.8 nm3/min for ladle refining of steel.
Powdered Iron
The sponge iron in the purified granular form. It is used in the manufacture of many useful articles articles by the metallurgy where (1) iron powders are first compacted by pressure alone into the approximate shape of the finished article; (2) the compact is then ‘sintered’ at a temperature ranging between approximately 950 and 1095o C in furnaces provided with a protective atmosphere to prevent oxidation; and (3) the sintered articles are then pressed or machined to their final shape.
Powder Metals
Fabrication technology in which fine metallic powder is compacted under high pressure and then heated at a temperature slightly below the melting point to solidify the material. Primary users of powder metal parts are auto, electronics and aerospace industries.
Precipitation Hardening (PH)
Hardening due to the precipitation of a constituent from a super-saturated solid solution upon quenching and then holding at a prescribed temperature below transformational range. A small group of stainless steels with high chromium and nickel content, with the most common types having characteristics close to those of martensitic (plain chromium stainless class with exceptional strength) steels. Heat treatment provides this class with its very high strength and hardness. Applications for PH stainless steels include shafts for pumps and valves as well as aircraft parts.
Pre-Paint
To paint a product in coil form and then manufacture it into a final part.
Press Forming
See Brake Press Bending.
Pretreated
Steel to which a chemical treatment has been applied to prepare it for future surface treatments such as painting. (See Bonderized, Light Special Treatment and Special Treatment).
Prime Coil
Any coil produced by the line that is not held for any out-of-spec or quality reasons.
Process Annealing
A heat treatment used to soften metal for further cold working. In ferrous sheet and wire industries, heating to a temperature close to but below the lower limit of the transformation range and subsequent cooling for working. In the non-ferrous industries, heating above the recrystalization temperatures at a time and temperature sufficient to permit the desired subsequent cold working.
Process Control System
The general form of a process control system is one in which a multiplicity of inputs, such as the physical and chemical characteristics of the raw materials, the energy levels, the machine settings, and so forth are used to provide desired outputs such as product quality, productivity, and minimum cost, or some selected combination of these. In addition, there may be other outputs required; for example, processing information for supporting functions such as accounting and evaluation.
Producer Gas
Producer gas is manufactured by blowing an insufficient supply of air for complete combustion, with or without the admixture of steam, through a thick, hot, sold-fuel bed. A large proportion of the original heating value of the solid fuel is recovered in the potential heat of carbon monoxide, hydrogen, tarry vapours, and some hydrocarbons, and in the sensible heat of the composite gas which also contains carbon dioxide and nitrogen.
Progressive Aging
Aging by increasing the temperature in steps or continuously during the aging cycle. Compare with interrupted aging and step aging.
Prompt Industrial Scrap
The scrap generated by steel consumers in making their products. It may consist of the unwanted portions of plate or sheet that has been cut or sheared to the desired final size and shape, trimmings resulting from stamping and pressing operations, machine turnings, rejected products scrapped during manufacture, short ends, flash from forgings, and other types of scrap.
Puddling Furnace
The process used for the production of wrought iron, pig iron and cast iron by means of chemical action. This process was invented in 1780. The older process, dry puddling, is known as Cort’s Process and the newer, wet puddling or pig boiling, is known as Hall’s Process.
Pull
An irregular transverse crack on the face of an ingot caused by restriction to free contraction during cooling in the mould.
Pulverized Coal Injection System (PCI)
A blast furnace enhancement to reduce an integrated mill’s reliance on coke (because of environmental problems with its production). Up to 30% of the coke charged into the blast furnace can be replaced by this talcum-like coal powder, which is injected through nozzles at the bottom of the furnace.