STEEL TERMS GLOSSARY: E - H
EARING - Wavy projections formed at the open end of a cup or shell rim in the course of deep drawing because of differences in directional properties. Also termed scalloping. See NONSCALLOPING.
EDGE FILING - A method whereby the raw or slit edges of strip metal are passed or drawn one or more times against a series of files, mounted at various angles. This method may be used for deburring only or filing to a specific contour including a completely rounded edge.
EDGE STRAIN OR EDGE BREAKS - Creases extending in from the edge of the temper rolled sheet.
EDGEWISE CURVATURE - (See CAMBER.)
EDGING - The dressing of metal strip edges by rolling, filing or drawing.
ELASTIC LIMIT - Maximum stress that a material will stand before permanent plastic deformation occurs.
ELECTRIC FURNACE STEEL - Steel made in any furnace where heat is generated electrically, almost always by arc.
ELECTRO-GALVANIZING - Galvanizing by electro deposition of zinc on steel.
ELECTROLYTIC TIN PLATE - BLACK PLATE that has been tin plated on both sides with commercially pure tin by electrode position (refer TIN PLATING).
ELECTROPLATING - The production of a thin coating of one metal on another by electro-deposition.
ELONGATION - As it pertains to the TENSILE TEST, the increase in length which occurs before the metal is fractured, when subjected to stress. This is usually expressed as a percentage of the original length and is a measure of the ductility of the metal. In SKIN PASS or TEMPER ROLLING, the increase in length of the material resulting from cold rolling, expressed as a percentage.
EMBOSSING - Raising or indenting a design in relief on a sheet or strip of metal by passing between rolls of desired pattern.
ENDURANCE LIMIT - Maximum alternating stress which a given material will withstand for an indefinite number of times without causing fatigue failure.
ENTRY MARK - A slight corrugation caused by the entry rolls of a roller leveling unit.
ERICHSEN TEST - Similar to the OLSEN TEST. Readings are in millimeters.
ETCHING - In metallography, the process of revealing structural details by the preferential attack of reagents on a metal surface.
EXTENSOMETER - An apparatus for indicating the deformation of metal, especially elongation, while it is subjected to stress.
FATIGUE - The phenomenon leading to fracture under repeated or fluctuating stress. Fatigue fractures are progressive, beginning as minute cracks and growing under the action of fluctuating stress.
FERRITE - The soft ductile almost pure iron phase that, together with the carbide phases, makes up the microstructure of steel at temperatures below the critical (1333°F).
FINISHES - The surface appearance of the various metals after final treatment such as rolling. etc. Over the years the following finishes have become recognized as standard in their respective fields.
1. BLACK PLATE
Dull Finish - a finish without luster produced by use of roughened rolls.
Bright Finish - a luster finish produced by use of rolls having a moderately smooth surface.
2. COLD ROLLED STEEL SHEETS
Commercial Finish - A dull satin surface texture produced by roughened rolls.
Commercial Bright Finish - Bright in appearance with a texture between luster and a very fine matte finish.
Luster Finish - Produced by use of ground and polished rolls. (Note - This is not a number 3 finish.)
3. COLD ROLLED STRIP STEELS
No. 1 Finish - A dull finish produced without luster by rolling on roughened rolls.
No. 2 Finish - A regular bright finish produced by rolling on moderately bright rolls.
No. 3 Finish - Best Bright Finish - A lustrous or high gloss finish produced by rolling on highly polished rolls - Also referred to as Mirror Finish.
4. TIN PLATE
Bright hot dipped finish.
Electro Matte Dull Finish.
Electro Bright Reflow Finish - produced by the in-the-line thermal treatment following electrodeposition.
FINISHING TEMPERATURE - The temperature at which final hot working is done. It is usually understood to be the steel temperature at the exit side of the last rolling stand of the hot strip mill.
FLAME ANNEALING - A process of softening a metal by the application of heat from a high temperature flame.
FLAT WIRE - A flat cold rolled, prepared edge section up to 1 V4" wide, rectangular in shape. Generally produced from hot rolled rods or specially prepared round wire by one or more cold rolling operations, primarily for the purpose of obtaining the size and section desired. May also be produced by slitting cold rolled flat metal to desired width followed by edge dressing.
FLOPPERS - Lines or ridges which are transverse to the direction of rolling and generally confined to the section midway between the edges of the coil as rolled. They are somewhat irregular and tend toward a flat arc shape.
FLUTING - Kinking or breakage due to curving of metal strip on a radius so small, with relation to thickness, as to stretch the outer surface above its elastic limit.
GAGES - (Metal) - Manufacturers' standard numbering systems indicating decimal thicknesses or diameters.
GALLING - The damaging of one or both metallic surfaces by removal of particles from localized areas due to seizure during sliding friction.
GALVANIZING - Coating steel with zinc and tin (principally zinc) for rustproofing purposes. Formerly for the purpose of galvanizing, cut length steel sheets were passed singly through a bath of the molten metal. Today's galvanizing processing method consists of uncoiling and passing the continuous length of successive coils either through a molten bath of the metal (termed Hot Dipped Galvanizing) or by continuously zinc coating the uncoiled sheet electrolytically (termed ELECTRO-GALVANIZING).
GALVANNEALED COATING - Galvannealed sheets are hot dipped zinc-coated sheets which have been processed to produce a zinc-iron alloy coating. This product does not have a spangle and is suitable for painting after cleaning. The alloy produced lacks ductility and powdering of the coating can occur during forming.
GHOST LINES (GHOST WELT LINES) - Lines running parallel to the rolling direction that appear in a panel when it is stretched. These lines may not be evident unless panel has been sanded or painted. (Not to be confused with leveler lines.)
GRAIN - A solid polyhedral (many sided) crystal consisting of groups of atoms bound together in a regular geometric pattern. In mill practice grains are usually studied only as they appear in one plane. (1) (Direction of.) Refers to grain fiber following the direction of rolling and parallel to edges of strip or sheets. (2) To bend across the grain is to bend at right angles to the direction of rolling. (3) To bend with the grain is to bend parallel to the direction of rolling.
GRAIN BOUNDARY - Bounding surface between crystals. When alloys yield new phases (as in cooling), grain boundaries are the preferred location for the appearance of the new phase.
GRAIN GROWTH - The increase in average steel grain size that accompanies heating to or slow cooling from elevated temperature.
GRAIN SIZE - The average diameter of grains of metal or, alternately, the number of grains per unit volume. In ferrite (room temperature), an increase in grain size lowers hardness but may also decrease ductility and impact resistance. In austenite, an increase in grain size increases hardenability.
GRAIN REFINEMENT - A technique of increasing the strength of steel by reducing the size of its constituent grains, usually through the addition of grain refining alloys such as niobium, vanadium, and/or aluminum.
GRAPHITIZING - Annealing a ferrous alloy in such a way that some or all of the carbon is precipitated as graphite.
HALF HARD TEMPER - (No.2 Temper.) - In low carbon cold-rolled strip steel, produced by cold rolling to a hardness near to but somewhat softer than full hard temper.
HARDENABILITY - A property that indexes the depth and distribution of hardness induced by quenching from a suitable tem.perature. (See JOMINY HARDENABILITY TEST)
HARDENED AND TEMPERED SPRING STEEL STRIP - A medium or high carbon quality steel strip which has been subjected to the processing sequence of heating, quenching and tempering.
HARDENING - Any thermal process which increases the hardness of a metal. Usually heating and quenching certain iron base alloys from a temperature either within or above the critical temperature range.
HARDNESS - Degree to which a metal will resist cutting, abrasion, penetration, bending and stretching. The indicated hardness of metals will differ somewhat with the specific apparatus and technique of measuring. For details concerning the various types of apparatus used in measuring hardness; See BRINELL HARDNESS, ROCKWELL HARDNESS, VICKERS HARDNESS, SCLEROSCOPE HARDNESS. TENSILE STRENGTH also is an indication of hardness.
HEALED OVER SCRATCH - A scratch that occurred in an earlier mill operation and was partially masked in subsequent rolling. It may open up during forming.
HEAT OF STEEL - The product of a single batch melting operation in a furnace, starting with the charging of raw materials and ending with the tapping of molten metal.
HEAT TREATMENT - Altering the properties of a metal by subjecting it to a sequence of temperature changes, time of retention at specific temperature and rate of cooling there from being as important as the temperature itself. Heat treatment usually markedly affects strength, hardness, ductility, malleability and similar properties of both metals and their alloys.
HSLA - (HIGH STRENGTH LOW ALLOY) - Comprises a specific group of steels with chemical composition specially developed to impart higher mechanical property values and, in certain of these steels, greater resistance to atmospheric corrosion than is obtainable from conventional carbon structural steels. High strength low alloy steel is generally produced with emphasis on mechanical property requirements rather than to chemical composition limits. It is not considered to be alloy steel.
HOT DIP - In steel mill practice. a process whereby ferrous alloy base metals are dipped into molten metal, usually zinc, tin, aluminum or terne, for the purpose of fixing a corrosion resistant coating.
HOT ROLLED - Hot rolled sheets are those that are reduced to required thickness at temperatures at which scale is formed and, therefore, carry hot mill oxide.
HOT ROLLED PICKLED - The hot rolled product which has been treated to remove the hot mill oxide.
HOT WORKING - Plastic deformation of metal at a temperature sufficiently high not to create strain hardening. The lower limit of temperature for this process is the recrystallization temperature.
HYDROGEN EMBRITTLEMENT - (1) Brittleness of metal, resulting from the occlusion of hydrogen (usually as a by-product of pickling or by co-deposition in electroplating). (2) A condition of low ductility resulting from hydrogen absorption and internal pressure developed subsequently.
