DC (Direct Chill) Casting
A continuous method of making ingots or billets for sheet or extrusion by pouring the metal into a short mold. The base of the mold is a platform that is gradually lowered while the metal solidifies, the frozen shell of metal acting as a retainer for the liquid metal below the wall of the mold. The ingot is usually cooled by the impingement of water directly on the mold or on the walls of the solid metal as it is lowered. The length of the ingot is limited by the depth to which the platform can be lowered; therefore, it is often called semi-continuous casting.

Dead Flat
Perfectly flat. As pertaining 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 ductility.

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 attainable in wire, strip, or sheet metal in the annealed state.

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

Removal of carbon from the outer surface of iron or steel, usually by heating in an oxidizing or reducing atmosphere. Water vapor, oxygen and carbon dioxide are strong decarburizes. 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 deformation of the metal. Deep-drawing quality sheet or strip steel, ordered or sold on the basis of suitability for deep-drawing.

Deep Drawing Steel (DDS)
Sheet of this designation should be used when Drawing Steel will not provide a sufficient degree of ductility for fabrication of parts having stringent drawing requirements, or applications that require the sheet be free from aging. This quality is made by special steelmaking and finishing practices.
Degassing Process
(In steel making) - Removing gases from the molten metal by means of a vacuum process in combination with mechanical action.

Delta Iron
Allotropic modification of iron, stable above 2552°F. to melting point. It is of body-centered cubic crystal structure.

Dent Resistant - BH Series
Sheet of this designation is produced from partially stabilized steel and offers a unique combination of as-received formability and final properties after fabrication.  Sheet of this designation combines strength and high formability.  Although this steel is non-aging at room temperature, it gains strength from work-hardening during fabrication and from carbon-aging during paint-baking.  (Sometimes  referred to as "bake hardenable.")
The removal of the surface defects from ingots, blooms, billets and slabs by means of a manual thermal cutting.


Removal of oxygen. In steel sheet, strip, and wire technology, the term refers to heat treatment in a reducing atmosphere, to lessen the amount of scale. (See Controlled Atmosphere Furnaces)
A process  used during melting and refining of steel to remove and / or chemically combine oxygen from the molten steel to prevent porosity in the steel when it is solidified.
Die Casting
The principal processes for casting near net shapes of non-ferrous metals such as zinc, aluminium, and zinc-aluminium alloy.
Lines of markings caused on drawn or extruded products by minor imperfections in the surface of the die.

Die Sinking
Forming or machining a depressed pattern in a die.

Dip transfer
A method of metal-arc welding in which fused particles of the electrode wire in contact with the molten pool are detached from the electrode in rapid succession by the short circuit current, which develops every time the wire touches the molten pool

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

See Dished Heads Glossary for more information.

  • WHAT
    Operation that injects a chemical mixture into a ladle full of hot metal to remove sulfur prior to its charging into the Basic Oxygen Furnace.
  • WHY
    Sulfur enters the steel from the coke in the blast furnace smelting operation, and there is little the steelmaker can do to reduce its presence. Because excess sulfur in the steel impedes its welding and forming characteristics, the mill must add this step to the steelmaking process.
Direct Reduced Iron (DRI)
  • WHAT
    Processed iron ore that is iron-rich enough to be used as a scrap substitute in electric furnace steelmaking.
  • WHY
    As mini-mills expand their product abilities to sheet steel, they require much higher grades of scrap to approach integrated mill quality. Enabling the mini-mills to use iron ore without the blast furnace, DRI can serve as a low residual raw material and alleviate the mini-mills' dependence on cleaner, higher-priced scrap.
  • HOW
    The impurities in the crushed iron ore are driven off through the use of massive amounts of natural gas. While the result is 97% pure iron (compared with blast furnace hot metal, which, because it is saturated with carbon, is only 93% iron), DRI is only economically feasible in regions where natural gas is attractively priced.

Doctor Blade Steel Strip
A hardened and tempered spring steel strip, usually blued, produced from approximately .85 carbon cold rolled spring steel strip specially 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.

The projected distance between the two ends of a drag line

Drag lines
Serrations left on the face of a cut made by thermal cutting.

(See Tempering)

Drawing Steel (DS)
Sheet of this quality has a greater degree of ductility and is more consistent in performance than Commercial Steel because of higher standards in production, selection and melting of the steel

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

A procedure for producing specialty tubing using a draw bench to pull tubing through a die and over a mandrel, giving excellent control over the inside diameter and wall thickness. Advantages of this technique are its inside and outside surface quality and gauge tolerance. Major markets include automotive applications and hydraulic cylinders.

Dressing of coil
Eliminating any damage or defects from the outer or inner diameter of the coil in preparation for shipping.

Drill Pipe
Pipe used in the drilling of an oil or gas well. Drill pipe is the conduit between the wellhead motor and the drill bit. Drilling mud is pumped down the center of the pipe during drilling, to lubricate the drill bit and transmit the drilled core to the surface. Because of the high stress, torque and temperature associated with well drilling, drill pipe is a seamless product.

Drill Rod
A term given to an annealed and polished high carbon tool steel rod usually round and center less ground. The sizes range in round stock from .013 to 1 ˝” 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 makers for punches, drills, taps, dowel pins, screw machine parts, small tools, etc.

Dry Film Thickness (DFT)
The thickness of the dry paint film.

Dry Rolled Finish
Finish obtained by cold rolling on polished rolls without the use of any coolant or metal lubricant, material previously plain pickled, giving a burnished appearance.

DS Type B Steel
Product intended for applications that require particularly severe drawing and forming.

Ability of steel to undergo permanent changes in shape without fracture at room temperature.

Dumping occurs when imported merchandise is sold in, or for export to, the domestic market at less than the normal value of the merchandise, i.e., a price which is less than the price at which identical or similar merchandise is sold in the comparison market, the home market (market of exporting country) or third-country market (market used as proxy for home market in cases where home market cannot be used). The normal value of the merchandise cannot be below the cost of production.

Dumping Margin
The amount by which the normal value exceeds the export price or constructed export price of the subject merchandise.

A category of stainless steel with high amounts of chromium and moderate nickel content. The duplex class is so named because it is a mixture of austenitic (chromium-nickel stainless class) and ferritic (plain chromium stainless category) structures. This combination was originated to offer more strength than either of those stainless steels. Duplex stainless steels provide high resistance to stress corrosion cracking (formation of cracks caused by a combination of corrosion and stress) and are suitable for heat exchangers, desalination plants, and marine applications.

The trade name applied to the first aluminum-copper-magnesium type of age-hardenable alloy (17S), which contains nominally 4% Cu, ˝ % Mg. The term is sometimes used to include the class of wrought aluminum-copper-magnesium alloys that harden during aging at room temperature.