Aluminum Basics

Aluminum is a popular metal for fabrication as it is very lightweight and easy to form. Its most common additives include magnesium, silicon, copper, and manganese to increase its strength and durability. You can read more about advantages and disadvantages, aluminum grades, and common applications below, as well as cost saving tips when using aluminum in your project.

Advantages & Disadvantages of Aluminum

Advantages

  • Malleable and flexible
  • Naturally resistant to rust and corrosion
  • Does not require finishing
  • Lightweight
  • Non-ferromagnetic
  • Excellent conductor of heat and electricity
  • Recyclable

Disadvantages

  • Less durable than steel
  • Easier to puncture and dent
  • High thermal conductivity can translate to weak welds and difficulty laser-cutting
  • Often more expensive than steel
  • High-strength grades can be brittle

Common Aluminum Sheet Metal Grades

Grade

Characteristics

5052-H32

Most common aluminum requested at Estes
Highest strength alloy of the more common non heat-treatable grades
Higher fatigue strength
Resists marine atmosphere and salt water corrosion
Excellent workability

3003-H14

Most widely-used aluminum alloy
Made of commercially-pure aluminum with added manganese
20% strength increase over the 1100 grade
Corrosion resistance & high workability
Non heat-treatable

6061-T4

Least expensive & most versatile of the heat-treatable aluminum alloys
Good mechanical properties & corrosion resistance
Solution heat treated and naturally aged
Softer and more malleable

6061-T6

Least expensive & most versatile of the heat-treatable aluminum alloys
Good mechanical properties & corrosion resistance
Solution heat treated and artificially aged; increased strength and resilience
Harder to form and impossible to form sharp edges
You can read more about the technical specifications of the aluminum we use at Estes in our Material Requirements blog series.
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Aluminum is infinitely recyclable and nearly 65% of all aluminum ever produced is still in use today.

Aluminum Grade Classifications

All aluminum grade classifications use a numbering system to express their properties.

Alloy Designations

The first digit refers to the major alloy element that is mixed with the aluminum in that grade (see table on the right).

The second digit refers to any modifications that have been made in impurity limits. Digits zero through 8 are assigned based on the number of changes to the original alloy.

The last two digits indicate the minimum aluminum content above 99%, expressed in hundredths of a percent.

 

For example, a 5052-H32 grade aluminum sheet would indicate that the major alloy element is magnesium, there have been no modifications to impurity limits, and the sheet contains 99.52% aluminum.

Wrought Aluminum Alloys

1xxx 99% Aluminum; no major alloy
2xxx Copper
3xxx Manganese
4xxx Silicon
5xxx Magnesium
6xxx Magnesium and Silicon
7xxx Zinc
8xxx Other Elements
Source: ESAB

Temper Designations

The dash following the 4-digit number expresses that the aluminum alloy has been tempered to change its properties. The letter distinguishes the type of tempering and any additional numbers clarify which processes were used.

Temper Designations

F As fabricated – Applies to products of a forming process in which no special control over thermal or strain hardening conditions is employed
O Annealed – Applies to product which has been heated to produce the lowest strength condition to improve ductility and dimensional stability
H Strain Hardened – Applies to products which are strengthened through cold-working. The strain hardening may be followed by supplementary thermal treatment, which produces some reduction in strength. The “H” is always followed by two or more digits
W Solution Heat-Treated – An unstable temper applicable only to alloys which age spontaneously at room temperature after solution heat-treatment
T Thermally Treated – To produce stable tempers other than F, O, or H. Applies to product which has been heat-treated, sometimes with supplementary strain-hardening, to produce a stable temper. The “T” is always followed by one or more digits
Source: ESAB

There are two main types of alloys: heat treatable and non-heat treatable, which determine which tempering methods are available to certain grades.

Heat-Treatable Alloys

Series 2xxx, 6xxx, and 7xxx are heat treatable alloys that gain optimal mechanical properties through thermal processes, most commonly solution heat treatment and aging.

Solution heat treatment involves two steps:

  1. Heating the alloy, usually to around 990 degrees Fahrenheit, to put the alloying elements or compounds into solution.
  2. Quenching the alloy, usually in water, to produce a supersaturated solution at room temperature.

This process is followed by aging, the precipitation of a portion of the elements or compounds from a supersaturated solution in order to yield desirable properties. Natural aging occurs at room temperature, while artificial aging relies on manual heating to around 320 degrees Fahrenheit.

 

Non-Heat Treatable Alloys

Series 1xxx, 3xxx, and 5xxx are non-heat treatable and use strain hardening to achieve optimum properties. This involves increasing strength through cold working.

 

Series 4xxx contains both heat treatable and non-heat treatable alloys.

There are two main types of alloys: heat treatable and non-heat treatable, which determine which tempering methods are available to certain grades.

Aluminum Alloys (800 × 1500 px)

Strain Hardening and Thermal Treatment

H Temper

In the strain hardened category, the first digit following the H refers to any additional treatments of the alloy. The second digit refers to the level of hardness.

H Temper - Strain Hardening

H1 Strain hardened only
H2 Strain hardened and partially annealed
H3 Strain hardened and stabilized
H4 Strain hardened and lacquered or painted
Source: ESAB

H Temper - Strength Hardening Degrees

Hx2 Quarter Hard
Hx4 Half Hard
Hx6 Three-Quarters Hard
Hx8 Full Hard
Hx9 Extra Hard
Source: ESAB

T Temper

In the thermally treated category, the first digit following the T refers to the method of thermal treatment utilized.

T Temper - Thermal Treatment

T1 Naturally aged after cooling from an elevated temperature shaping process, such as extruding.
T2 Cold worked after cooling from an elevated temperature shaping process and then naturally aged.
T3 Solution heat treated, cold worked and naturally aged.
T4 Solution heat treated and naturally aged.
T5 Artificially aged after cooling from an elevated temperature shaping process.
T6 Solution heat treated and artificially aged.
T7 Solution heat treated and stabilized (overaged).
T8 Solution heat treated, cold worked and artificially aged.
T9 Solution heat treated, artificially aged and cold worked.
T10 Cold worked after cooling from an elevated temperature shaping process and then artificially aged.
Source: ESAB

Continuing with our example of a 5052-H32 grade aluminum sheet, the -H32 distinction means that the sheet is non-heat treatable and has been strain hardened and stabilized at 1/4 hardness.

Applications of Aluminum

  • Food and beverage machinery and packaging
  • Light fixtures
  • Fireproof boxes and safes
  • Automobile and airplane frames
  • Siding, drains, and other fixtures in homes and other buildings
  • Cookware
  • Appliances such as washing machines and dryers, refrigerators, and small cooking appliances

Not sure what specifications are right for your project?

We can help!

Cost Saving Design Tips

Design for Manufacturability and Assembly (DFMA) is an essential component of any lean manufacturing strategy, supporting faster lead times by reducing reworks and waste, which can also save money and reduce downstream costs.

What are some ways you can simplify your design to save time and money on your next sheet metal aluminum project? Keep reading for our tips!

  • Use pins and fasteners instead of welding

Aluminum requires more intensive welding expertise because of its high thermal conduction and tendency to be brittle. If you can, using fasteners will streamline the production process and protect your parts from heat damage.

  • Minimize finishing processes

Aluminum is naturally corrosion-resistant and does not require much finishing at all. A popular aluminum finish is anodizing, but it is not necessary if you are trying to cut costs.

  • Avoid hemming

Because aluminum tends to be brittle, it also doesn’t hem very well.

  • Avoid tight bends on high-strength grades

Aluminum is not as flexible as some other metals, so tight bends may cause it to snap.