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Steel Industry Glossary

D

D&I (Drawn & Ironed)
Stock material primarily used for two piece beer and beverage cans. (Draw a cup approximately finished can diameter and iron the sidewall to the can height.) Primarily BA T1 materials matte tin plate 60-100 micro inch finish.

Deburris
Horizontal knife used to remove burrs after slitting.
 
Deep Drawing
The fabrication process of flat rolled steel to make drawn parts. The part is mechanically formed through or in a die. The blank diameter is reduced; the blank contracts circumferentially as it is drawn radially inward. (See Deep Drawing Applications).
 
Deep Drawing Applications
Parts/applications that require deep drawing in their fabrication.  Examples are motor shells, fenders, quarter panels, door panels.
 
Defect
1. Anything that renders the steel unfit for the specific use for which it was ordered.   What is defective for one customer may be prime steel for another. 2. A variety of quality problems in a coil. Examples are punchmarks, roll marks, oil spots, and scratches.
 
Deflector Roll
A roll used to change the direction of the strip.
 
Degas Heat
A heat of degas steel is a heat that is produced to extremely low carbon levels through vacuum degassing.
 
Delay Code
A four-character code used to identify the type and reason for a delay.
 
Delivery End
The exit end of the line.
 
Delivery Tail End
The outside lap of the produced coil on the delivery reel.
 
Demineralized Water
City water which is circulated through a series of three demineralizing filters to soften it and remove residuals. It is then delivered to a storage tank for use in overflowing the superheater elements and headers on the boiler during hydrostatic tests. Filling the superheaters with demineralized water prevents the raw water used in a hydrostatic test from entering the superheaters where it could cause corrosion problems
 
Descaling
The process of removing scale from the surface of steel. Scale forms most readily when the steel is hot by union oxygen with iron. Common methods of descaling are: (1) crack the scale by use of roughened rolls and remove by a forceful water spray, (2) throw salt or wet sand or wet burlap on the steel just previous to its passage through the rolls.
 
Dezincing
A coating defect consisting of the removal of the zinc oxide in a "C"enamel film by chemical reaction with food products. Dezincing appears as a lack of opacity in the film and usually occurs in a random pattern.
 
Dies (Galvanize)
Air pressure devices in the Sheet Mill which, depending on distance from coil, determine coating thickness by removing excess metal from the strip; the farther the die is from the steel, the heavier the coating - also called "knives" on this line.
 
Differential Coatings
Coatings on flat rolled products whereby the thickness of the coating on the one side is heavier than the other side. At Weirton Steel, the term is applied to a tin plate product which requires one side of the steel to have a heavier tin coating than the other side.
 
Dimentional Tolerance
A range by which a product's width and gauge can deviate from those ordered and still meet the order's requirements. (Also See Commercial Tolerance)
 
Diversion
1.
A situation that occurs when a coil/s intended for an order doesn't meet quality standards or customers specifications and is therefore diverted to meet another customer's specifications. In addition, coils can be diverted to complete another customer's order or for other reasons as necessary.  2. Removing a product from it's original order. Synonymous with Reapplication.
 
Diverted Coil (DRV)
A coil that is no longer being sent to its original order but is being sold elsewhere.
 
Dolomite
A material that is used to add magnesium oxide to the sinter.
 
Double (Cold) Reduced (DR)
1. Material that has been cold reduced in thickness twice.  The first reduction is at the tandem Mill (where it is reduced at five different locations) and the second is at the Weirlite Mill.  2. Plate given a second major cold reduction following annealing. Double reduced products are relatively hard, have limited ductility, and highly directional mechanical properties. Aim Rockwell hardness 30T hardness is 76; Aim yield strength (varying from materials) is 80,000 psi to 90,000 psi; approximate tensile strength is 90,000 psi.
 
DQ
"
Draw quality" = more flexible grade of steel. 
 
DR Plate
Double reduced steel produced on the Weirlite Mills.
 
Drawn & Ironed (D&I)
A process primarily used to manufacture two-piece beer or carbonated beverage can bodies, although some canned food product is packaged in steel D&I can bodies. An appropriately sized circular disk is drawn into a cup to approximately the finished can diameter. The side wall height is created by forcing the cup through a series of rings, ironing the metal thinner than the starting material thickness. Can bodies are coated with organic lacquers after forming.
 
Drawn
Mechanically formed by tension through or in a die.
 
Draw-Redraw (DRD)
Two-piece. Process for making two-piece cans in which a circular blank is drawn into a die to form a shallow cup and then is redrawn on a second or third die to produce a can body of the desired dimensions.  Plate is coated prior to the forming process.
 
Draw-Thin-Redraw (DTR)
An enhancement of the DRD process for making two-piece can body utilizing high tensile TFS that has an organic polymeric coating applied prior to the forming operations. The patented DTR process is a means of subjecting the coated feedstock to forming strains such that the metal and coating avoid compacting and subsequent sidewall burnishing, thus enhancing the integrity of the organic coating. The resultant sidewall is thinned during the drawing and redrawing operations, thus facilitating the specified can body dimensions using a smaller starting blank size than that required for DRD.
 
Draw Quality (DQ)
Flat-rolled products produced from either deep drawing rimmed steel or extra deep drawing aluminum killed steels. Special rolling and processing operations aid in producing a product, which can stand extreme pressing, drawing or forming, etc., without creating defects.
 
Dross
Sediment which settles in bottom of the ZINC pot on the galvanize line. Also top dross, which floats on surface of pot and is skimmed off. A different type of dross also occurs on the top of the zinc pot, which is skimmed off on a regular time frame.
 
Dry Film Weight
Dry coating film weight is normally calculated in grams per square meter(gm/m) or milligrams per square inch(mg/in). Accurate control of dry film weight is essential to ensure that the coating material will possess its intended properties of physical and chemical resistance.
 
Dryer
Dries the strip after a rinsing process.
 
DTR
A Weirton Steel developed and patented technique for producing a drawn two piece can. See Draw-Thin-Redraw.
 
Ductility
A qualitative, subjective property of material that indicates the extent to which it can be deformed without fracture in metal working operations such as rolling, extrusion, fabrication, etc. It is generally expressed as total permanent strain prior to fracture, measured as elongation or reduction of area during tensile testing.

 

 

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