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.
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.
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.
(In steel making) - Removing gases from the molten metal by means of a vacuum process in combination with mechanical action.
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.") De-seaming
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) Deoxidation
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.
Forming or machining a depressed pattern in a die.
See Dished Heads Glossary for more information.Desulphurization
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.
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.
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
Dressing of coil
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