Dajcor Aluminum

Aluminum Terms & Glossary

Aging Hardening

A process of aging that increases hardness and strength and ordinarily decrease ductility.


A substance composed of two or more metals or of a metal and a nonmetal intimately united usually by being fused together and dissolving in each other when molten.


Alumina is produced from bauxite by a complicated chemical process. It is a white powdery material, that is chemically comprised of aluminum and oxygen molecules (Al2O3).


A light silvery-grey metal chemical element with the atomic number of 13 and the Element Symbol is Al.

Aluminum Angle

Aluminum angle is a product which has two legs to form a 90-degree angle. It serves well both as structural material and trim. Beyond the inherent strength of the angle shape, the aluminum provides its inherent strength, corrosion resistance, and lightweight.

Aluminum Oxide

A compound that is formed when an aluminum surface is brought in contact with oxygen, causing a chemical reaction between the aluminum and the oxygen. The reaction produces a chemical compound, which acts as a transparent shield, protecting the aluminum from further oxidation without affecting its integrity and appearance.


conformity to or deviation from, specified angular dimensions in the cross section of a shape or bar

Anodised Aluminum

Metal with an anodic layer, produced by an electrolytic oxidation process in which a metal surface layer is converted to an oxide layer having protective, decorative or functional properties

architectural anodising aluminum

anodising to produce an architectural finish to be used in permanent, exterior and static situations where both appearance and long life are important


An amorphous clayey reddish-brown rock consisting mainly of hydrous aluminum oxides and aluminum hydroxides along with silica, silt, iron hydroxides and clay minerals.


A cylindrical-shaped piece of aluminum alloy, which is pressed through the die of an extrusion press to create aluminum extrusion products.


A hardened alloy steel disk with the same diameter as a die ring. It helps minimize deflection and supports the die and backer.

bright anodised aluminum

anodised metal with a high specular reflectance as the primary characteristic


mechanical roughening of a surface, typically with rotating brushes


mechanical finishing operation in which fine abrasives are applied to a metal surface by rotating fabric wheels for the purpose of developing a lustrous finish

chemical brightening

chemical treatment to improve the reflectivity of a surface

chemical polishing

polishing of a metal surface by immersion in a solution of chemical reagents

clear anodised aluminum

metal with a substantially colourless, translucent anodic oxidation finish

cold sealing

sealing at temperatures significantly below 100°C, but higher than room temperature

colour anodised aluminum

anodised metal coloured either during anodising or by subsequent colouring processes


inward curvature across the width of a flat product


the extent to which the inner and outer walls of round tube have a common centre of curvature


hollow cylinder in an extrusion press from which the billet is extruded


outward curvature across the width of a flat product


convex junction between two surfaces


difference in thickness between one of the edges and the centre of a rolled product


A customized opening in an extrusion press, through which a heated aluminum alloy is pressed. The shape of this opening determines the final shape of the extruded product, which is the cross-sectional shape of the opening in the die.

die holder

A component of an extrusion press that holds the extrusion die and its components. It is located between the container and press platen.

die ring

A cylindrical sleeve that holds the die and backer in axial relationship to each other.


A property of elasticity that determines how easily a material can be shaped or manipulated. Aluminum has high ductility, allowing for significant bending and stretching without creating stress fractures during the production process.

dummy block

A steel block that forms protection against back feeding between the hot billet and the ram in an extrusion process.

dyed anodised aluminum

metal with an anodic oxidation layer coloured by absorption of dye-stuff or pigments into the pore structure


deviation between the centres of curvature of the inner and outer walls of round tube

electrical conductivity

The ability of a metal to conduct or allow an electrical current to pass through it. For aluminum, this capacity is expressed as a percentage of the International Annealed Copper Standard. Which has a resistivity of 1/58 ohm-mm2/meter at 20°C.

electrolytically colour anodised aluminum

metal with an anodic oxidation layer that has been coloured by the electrolytic deposition of a metal or metal oxide into the pore structure


Etching is a method used to change or texturize the surface of aluminum, by permitting controlled corrosion through the use of an acid or another chemical agent.


Extrusion is defined as the process of shaping material, such as aluminum, by forcing it to flow through a shaped opening in a die. Extruded material emerges as an elongated piece with the same profile as the die opening.

extrusion butt

that portion of an extrusion billet that is left unextruded

extrusion die

block of steel having one or more holes of the required contour through which a billet is forced

extrusion press

machine consisting essentially of a container, a ram or other pressure-applying device, and a die, used for extrusion

extrusion press solution heat treatment

heating an alloy to a suitable temperature then extruding, while holding for sufficient time to allow one or more soluble constituents to enter into solid solution, where they are retained in a supersaturated state after quenching

extrusion ratio

the ratio of the cross-sectional area of the extrusion container to that of the extruded product

extrusion seam

region in an extruded product where metal has been welded together in the extrusion die because of high pressure and elevated temperature

Feeder Plate

A steel plate that is placed before the extrusion die in an extrusion press. The purpose of the feeder plate is to change the dimensions of an aluminum billet to produce a shape larger than the billet size.


concave junction between two surfaces


the characteristics of the surface of a product


the extent to which the surface of a product approaches a plane

furnace solution heat treatment

heating an alloy to a suitable temperature in a furnace and holding for a sufficient time to allow one or more soluble constituents to enter into solid solution, where they are retained in a supersaturated state after quenching

hard anodised aluminum

anodised metal on which the anodic oxidation finish has been produced with wear and/or abrasion resistance as the primary characteristic


The process of deliberately increasing the hardness of a metal, using processes such as drawing, hammering, rolling, or other physical processes. Other treatments including cooling, drying, crystallization, and heating can also be used for hardening.

Hot Tears

Transverse surface scars or separations along the length of the extruded profile caused by excess speed and/or temperature.

longitudinal extrusion seam

extrusion seam in a hollow profile or a tube, parallel to the extrusion direction, which has been formed after creating two or more streams of metal and rejoining them around the mandrel of a porthole or bridge die

matte finish

diffuse finish typically produced by rolling, etching, brushing or blast cleaning

mechanical polishing

polishing with a flexible rotating mop carrying an abrasive compound

mill finish

finish, naturally occurring after extruding

mirror finish

finish after rolling or polishing with high specular reflectivity

natural oxide film

oxide film that forms naturally on the metal and is relatively impervious to atmospheric attack


departure of the cross-section of a round tube, rod or bar or wire from a true circle

Polished aluminum

Polishing is a finishing process for smoothing a work piece’s surface using an abrasive and a work wheel or a leather strop. The removal of oxidization (tarnish) from metal objects is accomplished using a metal polish or tarnish remover. This process removes surface material, improving the surface and preparing it for buffing.

porthole die

extrusion die that incorporates a mandrel as an integral part of the die assembly


A product manufactured by extrusion or other processes that is long and continuous in ratio to its cross-section.


Also known as the stem, this is an attached rod or extensions of the main cylinder of an extrusion press that is used to apply force on the dummy block, to push the billet into the die.

Run-out Table

A long platform or table, attached to the exit of the extrusion press to help support and guide the hot extrusions.


treatment of anodised metal by hydrothermal processes carried out after anodising to close the pores of the anodic layer and to reduce the absorption capacity of the coating

Shear Strength

The amount of stress or shear that material can bear or withstand without fracturing.

shot blasting

projection of abrasive grit, e.g. sand, small particles of steel, glass, plastic beads or other materials, or a mixture of abrasive grit, water and air on a product in order to in order to obtain a roughened surface topography


The reduction of the extrusion due to such factors as cooling and speed of extrusion.

Solution Heat Treating

Heating an alloy at a suitable temperature for sufficient time to allow soluble constituents to enter into solid solution where they are retained in a supersaturated state after quenching.

solution heat treatment

heating an alloy to a suitable temperature for sufficient time to allow one or more soluble constituents to enter into solid solution, where they are retained in a supersaturated state after quenching


characteristic of having adjacent sides, planes or axes meeting at 90°


correcting operation of a drawn or extruded product, to fulfil the requirements concerning tolerances on form and dimension.


the extent to which the axis or the edge of a product approaches a straight line


This process involves straightening an extruded product by pulling the aluminum so that the length increases with a corresponding slight decrease in the cross-sectional dimensions.


Cracks or separation due to high extrusion speed or extrusion temperature.

Tensile Strength

The maximum tensile stress that a material is capable of withstanding without breaking under a gradually and uniformly applied load.


The range of permissible limits of variation or deviation of an object’s properties from a predetermined value.


term typically referring to the dies, mandrels, etc., used in the production of extruded or drawn profiles or tube

transverse extrusion seam

extrusion seam which is formed when two subsequent billets are welded together in the extrusion die


treatment of products in a rotating container in the presence of abrasives and water for deburring or to produce a variety of surface textures


The extent to which a product is twisted around its longitudinal axis

visible/exposed surface

surface of the semi-finished product which is intended to be visible in final use


The feasibility or practicality of an operation that is capable of the formation of various alloys with relative ease by extruding, forging, rolling or other processes.

Yield strength

The strength of metal to undergo stress or gradual progressive force, up to a level that it does not bring permanent deformation in the metal or changes the dimensions.
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