Metal Terminology (D-E)金属术语D-E

Metal Terminology¹ D

DEAD FLAT
Perfectly flat. As pertaining² to sheet, strip or plate. (See Stretcher Leveling)

DEAD SOFT ANNEALING
Heating metal to above the critical range and appropriately cooling to develop the greatest possible commercial softness or ductility³.

DEAD SOFT STEEL
Steel, normally made in the basic open-hearth furnace or by the basic oxygen process with carbon less than 0.10% and manganese in the 0.20-0.50% range, completely annealed.

DEAD SOFT TEMPER
(No. 5 TEMPER) - Condition of maximum softness commercially attainable⁴ in wire, strip, or sheet metal in the annealed state.

DEBURRING
A method whereby the raw slit⁵ edge of metal is removed by rolling or filing.

DECARBURIZATION
Removal of carbon from the outer surface of iron or steel, usually by heating in an oxidizing or reducing atmosphere. Water vapor⁶, oxygen and carbon dioxide are strong decarburizers. Reheating with adhering scale is also strongly decarburizing in action.

DEEP DRAWING
The process of cold working or drawing sheet or strip metal blanks by means of dies on a press into shames which are usually more or less cup-like in character involving considerable plastic deformation⁷ of the metal. Deep-drawing quality sheet or strip steel, ordered or sold on the basis of suitability for deep-drawing.

DEGASSING PROCESS
(In steel making) - Removing gases from the molten metal by means of a vacuum process in combination with mechanical action.

DELTA⁸ IRON
Allotropic modification⁹ of iron, stable above 2552癋. to melting point. It is of body-centered cubic crystal structure.

DEOXIDIZING
Removal of oxygen. In steel sheet, strip, and wire technology, the term refers to heat treatment in a reducing atmosphere, to lessen¹⁰ the amount of scale. (See Controlled Atmosphere Furnaces)

DIE-LINES
Lines of markings caused on drawn¹¹ or extruded¹² products by minor¹³ imperfections in the surface of the die.

DIE SINKING
Forming or machining a depressed¹⁴ pattern in a die.

DISH
A concave surface departing from a straight line edge to edge. Indicates transverse or across the width.

DOCTOR BLADE STEEL STRIP
A hardened and tempered spring steel strip, usually blued, produced from approximately .85 carbon cold rolled spring steel strip specially¹⁵ selected for straightness and good edges. Sometimes hand straightened or straightened by grinding and cut to desired lengths. This product is used in the printing trade as a blade to uniformly remove excess ink (“dope”) from the rolls; hence its name.

DRAWING BACK
Reheated after hardening to a temperature below the critical for the purpose of changing the hardness of the steel. (See Tempering)

DRILL ROD
A term given to an annealed and polished high carbon tool steel rod usually round and centerless ground. The sizes range in round stock from .013 to 1 ?#148; diameter. Commercial qualities embrace water and oil hardening grades. A less popular but nevertheless standard grade is a non-deforming quality. Drill Rods are used principally by machinists and tool and die makers¹⁶ for punches, drills, taps, dowel pins, screw machine parts, small tools, etc.

DRY ROLLED FINISH
Finish obtained by cold rolling on polished rolls without the use of any coolant or metal lubricant, material previously¹⁷ plain pickled, giving a burnished¹⁸ appearance.

DUCTILITY
The property of metals that enables them to be mechanically deformed¹⁹ when cold, without fracture. In steel, ductility is usually measured by elongation and reduction of area as determined²⁰ in a tensile test.

DURALUMIN
The trade name applied²¹ to the first aluminum²²-copper²³-magnesium type of age-hardenable alloy²⁴ (17S), which contains nominally²⁵ 4% Cu, ?% Mg. The term is sometimes used to include the class of wrought²⁶ aluminum-copper-magnesium alloys²⁷ that harden during aging at room temperature.

Metal Terminology E

EARING
Wavy projections²⁸ formed at the opera end of a cup or shell in the course of deep drawing because of differences in directional properties. Also termed scallop. (See Non-Scalloping Quality Strip Steel)

EDGES
Many types of edges can be produced in the manufacture of flat rolled metal products. Over the years the following types of edges have become recognized as standard in their respective fields.

COPPER BASE ALLOYS
Slit, Slit and Edge Rolled, Sheared²⁹, Sawed, Machined or Drawn,

SHEET STEELS OR ALUMINUM SHEET
Mill Edge, Slit Edge or Sheared Edge.

STRIP STEELS and STAINLESS³⁰ STRIP
No. 1 Edge - A smooth, uniform, round or square edge, either slit or filed or slit and edge rolled as specified³¹, width tolerance³² +/-.005”.

No. 2 Edge - A natural round mill edge carried through from the hot rolled band. Has not been slit, filed, or edge rolled. Tolerances³³ not closer than hot-rolled strip limits.

No. 3 Edge - Square, produced by slitting³⁴ only. Not filed. Width tolerance close.

No. 4 Edge - A round edge produced by edge rolling either from a natural mill edge or from slit edge strip. Not as perfect as No. 1 edge. Width tolerances liberal.

No. 5 Edge - An approximately square edge produced by slitting and filing or slitting and rolling to remove burr.

No. 6 Edge - A square edge produced by square edge rolling, generally from square edge hot-rolled occasionally from slit strip. Width tolerances and finish not as exacting³⁵ as No. 1 edge.

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 dressing³⁶ of metal strip edges by rolling, filing or drawing.

ELASTIC³⁷ LIMIT
Maximum stress that a material will stand before permanent deformation occurs.

ELECTRIC FURNACE STEEL
Steel made in any furnace where heat is generated electrically, almost always by arc. Because of relatively³⁸ high cost, only tool steels and other high-value steels are made by the electric furnace process.

ELECTROCLEANING
(Electrolytic Brightening) - An anodic treatment. A cleaning, polishing, or oxidizing treatment in which the specimen³⁹ or work is made the anode in a suitable electrolyte; an inert⁴⁰ metal is used as cathode and a potential is applied.

ELECTRO-GALVANIZING
Galvanizing by electrodeposition of zinc⁴¹ on steel.

ELECTROLYTIC POLISHING
(See Electrocleaning)

ELECTROLYTIC TIN PLATE
Black Plate that has been tin plated on both sides with commercially pure tin by electrodeposition. (See Tin Plating)

ELECTROPLATING
The production of a thin coating of one metal on another by electrodeposition. It is very extensively used in industry and is continuing to enlarge its useful functions. Various plated metals and combinations thereof are being used for different purpose to illustrate⁴²:

1. Decoration and protection against corrosion…………………...copper, nickel and chromium.

2. Protection against corrosion…………………………………...cadmium or zinc

3. Protection against wear………………………………………..chromium

4. Build-up of a part or parts undersize…………………………...chromium or nickel

5. Plate for rubber adhesion………………………………………brass⁴³

6. Protection against carburization and for brazing operations…......copper and nickel

ELONGATION
Increase in length which occurs before a 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.

EMBOSSING
Raising or indenting⁴⁴ a design in relief on a sheet or strip of metal by passing between rolls of desired pattern. (See Patterned or Embossed Sheet)

ENDURANCE LIMIT
Maximum alternating stress, which a given material will withstand for an indefinite number of times, without causing fatigue⁴⁵ failure.

ERICHSEN TEST
Similar to the Olsen Test. Readings are in millimeters.

ETCHING
In metallography, the process of revealing structural⁴⁶ details by the preferential attack of reagents on a metal surface.

EUTECTOID STEEL
Steel representing the eutectoid composition of the iron carbon system, with about 0.80% to 0.83% carbon, the eutectoid temperature being about 1333癋. Such steel in the annealed condition consists exclusively of pearlite. Steels with less than this quota⁴⁷ of carbon are known as hypo-eutectoid and contain free ferrite in addition to the pearlite. When more carbon is present, the steel is known as hyper-eutectoid and contains free cementite. The presence of certain elements, such as nickel or chromium, lowers the eutectoid carbon content.

EXPANDER STEEL
Hardened and tempered, blue polished. Carbon content about 1.00, Chromium .17. Used for the expanders in oil piston⁴⁸ rings. Hardness 30 N 70 to 73. Range of sizes run for grooves⁴⁹ 3/32” to ?#148; wide with the steel approximately .003% less than the grooves and thickness from .012 to .020”.

EXTENSOMETER
An apparatus⁵⁰ for indicating the deformation of metal while it is subjected to stress.

EXTENSOMETER TEST
The measurement of deformation during stressing in the elastic range, permitting determination of elastic properties such as proportional limit, proof stress, yield strength by the offset⁵¹ method and so forth⁵². Requires the use of special testing equipment and testing procedures such as the use of an extensometer or the plotting of a stress-strain diagram.

EXTRA HARD TEMPER
In brass mill terminology, Extra Hard is six B & S numbers hard or 50.15% reduction from the previous annealing or soft stage.

EXTRA SPRING TEMPER
In brass mill terminology, Extra Spring is ten numbers hard or 68.55% reduction in thickness from the previous annealing or soft stage.

EXTRUSION
Shaping metal into a chosen continuous form by forcing it through a die of appropriate shape