Aluminium Alloy Properties: Bending
One of aluminium’s most useful properties is formability. With bending and folding being one of the most common aluminium fabrication processes we work with. We often get asked which aluminium alloy bends the best, and today we’re going to run through the properties of each alloy and solve your question.
Properties
High purity aluminium is soft and ductile, however bending is still a delicate process.
Many applications where aluminium alloy¹ is the best material choice, formability is the key property that must be accounted for.
Heat treatment procedures are common place for aluminium alloy production. In regular circumstances pure aluminium is easier to work with than alloys. However other properties of alloys will make them a superior choice, depending on the application.
A brief overview below:
Series 1xxx 99% Pure
Little structure, extremely ductile in the annealed condition and excellent corrosion resistance.
Series 2xxx Copper
Excellent machinability, limited cold formability (unless annealed), less corrosion resistant and usually anodised.
Series 3xxx Manganese
Feature no significant loss in ductile or corrosion resistance, and exhibit very good formability. Best option for forming applications.
Series 4xxx Silicon
Lower melting point, excellent for welding wire.
Series 5xxx Magnesium
Good combination of high strength, corrosion resistance, formability, and weldable.
Series 6xxx Magnesium-Silicon
Mainly used in architectural applications, these heat treatable alloys exhibit great strength, good corrosion resistance, and formability.
Series 7xxx Zinc–Magnesium & Aluminum–Zinc–Copper
High strength, hard to form.
Formability
The difference in chemical composition of aluminium and it’s alloys is what created their formability properties.
Aluminium Allow Designation – Wrought alloys
| Alloy Series | Principal Alloying Element | Heat treatment | Atoms in solution | Work Hardening | Precipitation Hardening |
| 1xxx | 99.000% Minimum Aluminium | Non-heat treatable | X | ||
| 2xxx | Copper | Heat treatable | X | (X) | X |
| 3xxx | Manganese | Non-heat treatable | X | X | |
| 4xxx | Silicon | Non-heat treatable | X | X | |
| 5xxx | Magnesium | Non-heat treatable | X | X | |
| 6xxx | Magnesium and Silicon | Heat treatable | X | (X) | X |
| 7xxx | Zinc | Heat treatable | X | (X) | X |
| 8xxx | Other Elements | Heat treatable | X | (X) | X |
Thickness and bend radius
Another factor to consider is that during the process of bending, the metal hardens and strengthens by reason of the working effect. Apart from alloy selection, thickness and bend radius are also critical factors that must be considered. Learn about the permitted 90o bending Radii:
Aluminum Minimum Bend Radii for 90 Degree Cold Forming of Sheet and Plate
| Alloy | Temper | RADII FOR VARIOUS THICKNESSES EXPRESSED IN TERMS OF THICKNESS “t” | |||||||
| 0.397mm | 0.798mm | 1.588mm | 3.175mm | 4.763mm | 6.35mm | 9.525mm | 12.7mm | ||
| 3003 | H12 | 0 | 0 | 0 | 1/2t | 1t | 1t | 1.5t | 2t |
| H14 | 0 | 0 | 0 | 1t | 1t | 1.5t | 2t | 2.5t | |
| H16 | 1/2t | 1t | 1t | 1.5t | 2.5t | 3t | 3.5t | 4t | |
| 3105 | H12 | 0 | 0 | 0 | 1/2t | 1t | 1t | 1.5t | 2t |
| H14 | 0 | 0 | 0 | 1t | 1.5t | 1.5t | 2t | 2.5t | |
| H16 | 1/2t | 1t | 1t | 1.5t | 2.5t | 3t | 3.5t | 4t | |
| 5052 | H32 | 0 | 0 | 1t | 1.5t | 1.5t | 1.5t | 1.5t | 2t |
| H34 | 0 | 1t | 1.5t | 2t | 2t | 2.5t | 2.5t | 3t | |
| H36 | 1t | 1t | 1.5t | 2.5t | 3t | 3.5t | 4t | 4.5t | |
| H38 | 1t | 1.5t | 2.5t | 3t | 4t | 5t | 5.5t | 6.5t | |
| 5086 | H32 | 0 | 1/2t | 1t | 1.5t | 1.5t | 2t | 2.5t | 3t |
| 5454 | O | 0 | 1/2t | 1t | 1t | 1t | 1.5t | 1.5t | 2t |
| H32 | 1/2t | 1/2t | 1t | 2t | 2t | 2.5t | 3t | 4t | |
| H34 | 1/2t | 1t | 1.5t | 2t | 2.5t | 3t | 3.5t | 4t | |
| 6061 | T6 | 1t | 1t | 1.5t | 2.5t | 3t | 3.5t | 4.5t | 5t |
Percentage of Elongation
The percentage of elongation and difference between yield strength / tensile strength is also important with regards to alloy formability.
This rule states the higher the elongation value, the wider the range between yield and tensile strength, the better the formability.
Refer to the table below to review the fomrability of some common alloys.
| Alloy | General Availability | Typical Characteristics* | Specified Mechanical Properties
Where range is shown, property varies with specific width and/or thickness dimensions |
||||||||||||||||
| Temper | Flat sheet | coil sheet | cut to length sheet | plate | corrosion resistant | cold workability | machinability | brazability | Weldability | ||||||||||
| gas | arc resistance, spot & steam | ||||||||||||||||||
| Tensile Strength – Ksi | Elongation in 2” or 4 times diameterpercent minimum | ||||||||||||||||||
| Ultimate | Yield | ||||||||||||||||||
| Minimum | Maximum | Minimum | Maximum | Sheet | Plate | ||||||||||||||
| Non-heat treatable | 1100 | O | X | X | X | – | A | A | D | A | A | A | B | 11 | 15.5 | 3.51 | – | 15-30 | – |
| H14 | X | X | X | – | A | A | C | A | A | A | A | 16 | 21 | 141 | – | 3-9 | – | ||
| F | – | – | – | X | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
| 3003 | O | X | X | X | – | A | A | D | A | A | A | B | 14 | 19 | 51 | – | 14-25 | – | |
| H14 | X | X | X | – | A | B | C | A | A | A | A | 20 | 26 | 171 | – | 1-7 | – | ||
| F | – | – | – | X | – | – | – | – | – | – | – | – | – | – | – | – | – | ||
| 5052 | O | X | X | X | – | A | A | D | C | A | A | B | 25 | 31 | 9.51 | – | 15-20 | – | |
| H32 | X | X | X | X | A | B | C | C | A | A | A | 31 | 38 | 231 | – | 4-9 | 11-12 | ||
| H34 | X | X | X | – | A | B | C | C | A | A | A | 34 | 41 | 261 | – | 3-7 | – | ||
| heat-treatable | Bare
2024 |
O3 | X | – | – | X | C | B | D | D | D | C | B | – | 32 | – | 14 | 12 | 12 |
| T3 | X | – | – | – | C | C | B | D | D | C | A | 63-64 | – | 42 | – | 10-15 | – | ||
| T351 | – | – | – | X | C | C | B | D | D | C | A | 56-64 | – | 40-41 | – | – | 4-12 | ||
| T422 | – | – | – | – | C | C | B | D | D | C | A | 58-62 | – | 38 | – | 12-15 | 4-12 | ||
| Alclad 2024 | O3 | X | X | – | X | A | B | D | D | D | C | B | – | 30-32 | – | 14 | 10-12 | 12 | |
| T3 | X | – | – | – | A | D | B | D | D | C | A | 58-63 | – | 39-40 | – | 10-15 | – | ||
| T351 | – | – | – | x | a | d | b | d | d | c | a | 56-63 | – | 40-41 | – | – | 4-8 | ||
| T422 | – | – | – | – | a | d | b | d | d | c | a | 55-61 | – | 34-38 | – | 10-15 | 4-12 | ||
| 6061 | O31 | X | X | – | X | A | A | D | A | A | A | B | – | 22 | 12 | 12 | 10-18 | 16-18 | |
| T4 | X | – | – | – | A | C | C | A | A | A | A | 30 | – | 16 | – | 10-16 | – | ||
| T6 | X | – | – | – | A | C | C | A | A | A | A | 42 | – | 35 | – | 4-10 | – | ||
| T651 | – | – | – | X | A | C | C | A | A | A | A | 40-42 | – | 35 | – | – | 6-10 | ||
| T422 | – | – | – | – | A | C | C | A | A | A | A | 30 | – | 14 | – | 10-16 | 16-18 | ||
| Bare
7075 |
O1 | X | – | – | – | C | D | D | D | D | D | B | – | 40 | – | 21 | 10 | – | |
| T6 | X | – | – | – | C | D | B | D | D | D | B | 76-77 | – | 65-66 | – | 7-8 | – | ||
| T651 | – | – | – | X | C | D | B | D | D | D | B | 67-77 | – | 53-66 | – | – | 2-8 | ||
| Alclad 7075 | O1 | X | X | – | – | A | B | C | D | D | D | B | – | 36-39 | – | 20-21 | 9-10 | – | |
| T6 | X | – | – | – | A | D | B | D | D | D | B | 68-75 | – | 58-64 | – | 5-8 | – | ||
Notes
Ratings A, B, C, D are relative in decreasing order of merit. Weldability and brazability ratings are specifically defined as:
A – Generally weldable by all commercial procedures and methods.
B – Weldable with special technique or specific applications which justify preliminary trials or testing to develop welding procedure and weld performance.
C -Limited weldability because of crack sensitivity or loss on resistance to corrosion, and all mechanical properties.
D – No commonly used welding methods have so far been developed.
1 – These yield strengths not determined unless specifically requested.
2 – Although sheet and plate are not sold in this temper, material heat treated from any temper by the user should attain the mechanical properties applicable to this temper.
3 – Annealed (0 temper) material shall, upon heat treatment, be capable of developing the mechanical properties applicable to T 42 temper material.
4 – Annealed (0 temper) material shall, upon heat treatment and aging, be capable of developing the mechanical properties applicable to T 67 temper material.
Summary
Our post has covered some common aluminium alloys and their formability properties. If you’ve got an aluminium project you’d like a quote on, contact our specialist team today.