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Aluminium: T

Temper Designations

There are two systems of letters and digits used, after the alloy designation number, to define and describe the temper of an aluminium alloy. The following is only an outline guide to these systems. For the strain hardening alloys of 1xxx, 3xxx and 5xxx series the following is used:- O = Annealed, soft F = As Fabricated H1x = Strain Hardened only H2x = Strain Hardened and partly annealed. H3x = Strain Hardened and stabilised H4x = Strain Hardened and organically coated with an oven cure. The second number shown as x above indicates the final degree of hardness or strength. 2 = quarter hard 4 = half hard 6 = three quarter hard 8 = fully hard. For the heat treatable alloys of the 2xxx, 6xxx,7xxx and 8xxx series the following applies. T1 = cooled from a high temperature forming process and naturally aged. T2 = cooled from a high temperature forming process cold worked and naturally aged. T3 = solution treated, cold worked and naturally aged. T4 = solution treated and naturally aged. T5 = cooled from a high temperature forming process and age hardened by heat treatment. T6 = solution treated and age hardened. T7 = solution treated and deliberately overaged T8 = solution treated, cold worked and age hardened T9 = solution treated, age hardened then cold worked. Additional numbers may also appear to indicate variations in treatment that can significantly influence the condition of the alloy.

Temper Rolling

A controlled cold rolling procedure performed to develop specific mechanical properties in a work piece.


The characteristic structural and mechanical properties produced by mechanical working and/or thermal treatments.

Related terms: Temper Designations

Tensile Strength, Ultimate Tensile Strength (UTS)

The maximum load, in tension, that a material can withstand before breaking. It is calculated as a breaking load for a standard cross section area.

Tensile Test

A procedure to measure the mechanical properties of a representative test piece in tension. The test piece is progressively loaded in tension and its gauge length plotted against the applied load generally to the point of fracture. The Proof Stress (Rp) and Tensile Strength (Rm) values are then determined.

Tension Levelling, Roller Levelling

Flattening of sheet, strip or coil metal by passing it through a roll train staggered rolls. Levelling is achieved by precisely bending metal strip back and forth as it's passed through a series of small-diameter offset rolls. The material is usually also under tension loading.

Tin Foil, Cooking Foil, Foil, Kitchen Foil

Cold rolled aluminium flat product less than 250 microns in thickness. Usage includes kitchen foil (cooking foil) and foil trays for food. Kitchen Foil is often incorrectly referred to as Tin Foil.


The permissible limit, or limits, of variation to a specified parameter such as a dimension or weight, usually expressed as 'plus' or 'minus' value or percentage on that quantity.

Torsion Test

A test in which a sample is twisted axially for a given number of revolutions. It may be conducted to destruction or to demonstrate that the material can withstand a specific amount of twisting.

Traffic Marks, Fretting

Abrasions, usually dark in colour, resulting from relative movement, or rubbing, between contacting metal surfaces during transit.

Triplate, Transition Joint

An explosively bonded bimetal flat bar that comprises a layer each of steel and marine-grade aluminium (alloy 5083) usually with an interlayer of pure aluminium. It is used for the on site welding of aluminium to steel, especially in shipyards and for offshore structures.