STEEL TERMS GLOSSARY: O - R
OFFAL - The material trimmed from blanks or formed panels.
OIL CAN (OIL CANNING) - Refers to an area in a formed panel that when depressed slightly will recover its original contour after the depressing force is removed.
OLSEN (DUCTILITY) TEST - A method of measuring the ductility and drawing properties of strip or sheet metal which involves determination of the width and depth of impression. The test, simulating a drawing operation, is made by a standard steel ball under pressure, continuing until the cup formed from the metal sample fractures. The height of the cup at fracture is read in thousandths of an inch. This test is sometimes used to detect stretcher straining and coarse grain and indicates the surface finish after drawing, similar to the ERICHSEN ductility test.
OPEN COIL ANNEALING - A BATCH ANNEAL process where adjacent coil laps are separated by wire spacers prior to annealing permitting complete exposure of the steel surface to the anneal atmosphere speeding up heating and cooling and promoting a more uniform heat distribution. Often used with an oxidizing atmosphere to produce decarburized steel products.
ORANGE PEEL - (effect) - A surface roughening (defect) encountered in forming products from metal stock that has a coarse grain size. It is due to uneven flow or to the appearance of the overly large grains usually the result of annealing at too high a temperature. Also referred to as ”pebbles" and "alligator skin".
OSCILLATED WOUND OR SCROLL WOUND - A method of even winding metal strip or wire onto a reel or mandrel wherein the strands are uniformly over-lapped. Sometimes termed "stagger wound" or "vibrated wound". The opposite of RIBBON WOUND.
PARALLELISM - The maximum thickness variation on a line perpendicular to the rolling direction across the strip width, but no closer than 3/8" to the edges.
PATTERNED OR EMBOSSED SHEET - A sheet product on which a raised or indented pattern has been impressed on either one or both surfaces by the use of rolls.
PEARLITE - Lamellar micro structure resembling mother of pearl. A compound of iron and carbon occurring in steel as a result of the transformation of austenite into aggregations of ferrite and iron carbide.
PHOSPHORUS - (Chemical Symbol P) - A nonmetallic element that is usually undesirable in steel. When added as an alloy, it is used as either a low cost strengthener in low carbon steel or to enhance machinability.
PHOTOMICROGRAPH - A photographic reproduction of any object magnified more than ten diameters.
PHYSICAL PROPERTIES - Those properties familiarly discussed in physics, exclusive of those defined as mechanical properties; for example; density, electrical conductivity, co-efficient of thermal expansion. This term often has been used to describe mechanical properties, but this usage is not recommended. (See MECHANICAL PROPERTIES.)
PICKLING - The process of chemically removing oxides and scale from the surface of a metal by the action of water solutions of inorganic acids.
PICKLING PATCH - A defect attributable to faulty pickling leaving areas from which the oxide has not been completely removed.
PICKLE STAIN - Discoloration present after pickling.
PICKUP- Metal particles adhering to a work roll or tool which cause a series of dents, scratches, or pits on a sheet or part.
PIG IRON -Iron produced by reduction of iron ore in a blast furnace. Pig iron contains approximately 92% iron and about 3.5% carbon. The balance is largely silicon and manganese with small percentages of phosphorus, sulphur and other impurities.
PINCHERS - Long fern like, chevron creases usually diagonal to the direction of rolling.
PINHOLES - Microscopic imperfections in coatings, (microscopic bare spots); also microscopic holes penetrating through a layer or thickness of light gage metal.
PIPE - Shrinkage cavity, essentially inverted cone-like in shape, which occurs in the approximate center, at the top and reaching down into a casting; caused by the shrinkage of cast metal upon solidification.
PIT - A sharp depression in the surface of the metal.
PRIMES - Metal products, such as sheet and plate. of the highest quality and free from visible surface defects.
PROCESS ANNEALING - In the sheet and wire industries, a process by which a ferrous alloy is heated to a temperature close to, but below, the lower limit of the transformation range and is subsequently cooled. This process is applied in order to soften the alloy for further cold working.
PRODUCT ANALYSIS - Chemical analysis as determined from a sample taken from the finished steel product. Since it is subject to segregation, it is not as representative as the LADLE ANALYSIS.
PROFILOMETER - A testing instrument that measures SURFACE TEXTURE.
PUNCH - The moveable male part that forces the metal into the female die in equipment for sheet drawing, blanking, coining, emhossing and the like.
PUNCHING - Shearing holes in sheet metal with punch and die.
PYROMETER - An instrument used for measuring elevated temperatures.
QUARTER HARD - (No.3 Temper) - In low carbon cold-rolled strip steel, a medium soft temper produced by a limited amount of cold rolling after annealing.
QUENCHING - In the heat treating of metals, the step of cooling metals rapidly in order to obtain desired properties; most commonly accomplished by immersing the metal in oil, water, or molten salt.
QUENCH HARDENING - A process of hardening a ferrous alloy of suitable composition by heating within or above the transformation range and cooling at a rate sufficient to increase the hardness substantially. The process usually involves the formation of martensite.
RADIANT TUBE ANNEALING BOX - A box which is heated inside by means of tubes in which gas is burned; the hot tubes radiate their heat to the inner covered stack of metal, standing on the base of the box. Usually a protective atmosphere is maintained in the inner cover to protect the metal from oxidation.
R-BAR (r) - The average STRAIN RATIO, an index of sheet steel resistance to thinning (drawability) during deep drawing. Normally associated with aluminum killed, drawing Quality cold rolled products, an r of 1.0 indicates equal flow strength in all directions while higher values indicate greater resistance to thinning through the cross section than to flow down the plane of the sheet. "Good" AK DQ cold rolled sheet steel typically will exhibit r values in the range of 1.4 - 2.2.
RECOVERY - The first stage of annealing, cold reduced steel recovery is the relief of localized stresses induced by cold rolling. It occurs at relatively low temperatures.
RECOVERY ANNEALING - A low temperature annealing process designed to impart limited ductility to full hard cold reduced steel without substantially altering as-rolled strength or microstructure.
RECRYSTALLIZATION - The second stage of annealing cold reduced steel, recrystallization is the replacement of the highly stressed cold worked grain structure by new. virtually stress free-grains. The process is accomplished by annealing above a specific temperature for a specific time.
RECRYSTALLIZATION TEMPERATURE - The approximate minimum temperature at which complete recrystallization of a cold worked metal occurs within a specified time.
REEL BREAKS (REEL KINKS) - Transverse breaks or ridges on successive inner laps of a coil which are the result of crimping the lead end of the coil into a gripping segmented mandrel.
REPHOSPHORIZING - Addition of phosphorus to steel to increase strength punchability and machinability.
RESIDUALS - Incidental or "tramp" elements that are not specified but are included into steel from raw materials and refractories used in steelmaking.
RESISTANCE WELDING - A type of welding process in which the work pieces are heated by the passage of an electric current through the area of contact. Such processes include spot welding, seam or line welding and percussion welding. Flash and butt welding are sometimes considered as resistance welding processes.
RIDGE - A longitudinal line where the thickness of the metal is slightly greater than the thickness adjacent.
RIBBON WOUND - A term applied to a common method of winding strip steel layer upon layer around an arbor or mandrel.
RIMMED STEEL - A low carbon steel in which incomplete deoxidation results in the evolution of gas from the molten metal in the ingot mold. When poured into a bottle top mold, the steel material is called CAPPED STEEL. RIMMED STEEL is poured into open top molds.
RIM ZONE - The surface layers of capped and rimmed steels that are lower in carbon and other impurities (due to segregation) and also sounder than the core.
ROCKWELL HARDNESS (TEST) - A standard method for measuring the hardness of metals. The hardness is expressed as a number related to the depth of residual penetration of a steel ball or diamond cone ("brale") after a minor load of 10 kilograms has been applied to hold the penetrator in position. This residual penetration is automatically registered on a dial when the major load is removed from the penetrator. Various dial readings combined with different major loads, give "scales" designated by letters varying from "A" to "H"; the "B" and "C" scales are most commonly in use.
ROLLED IN SCALE - Surface imperfections caused by rolling un-removed iron oxide scale into the steel surface during hot rolling.
ROLLER LEVELER - A series of small diameter staggered rolls used primarily to improve flatness and/or to remove yield point elongation.
ROLLER LEVELER BREAKS - Obvious transverse breaks usually 1/8 to 1/4 inches apart caused by the sheet fluting during roller leveling. These will not be removed by stretching.
ROLLER LEVELER LINES - lines running transverse to the direction of leveling. These may be seen upon stoning or light sanding after leveling and before drawing. Moderate stretching will usually remove them.
