What is 6061 aluminum alloy？
6061 aluminum is a super-hard aluminum alloy primarily composed of magnesium-silicon with excellent processing performance, excellent welding characteristics, and ease of electroplating. It also boasts high toughness and remains unchanged after processing, making it easy to polish and oxidize. In the aluminum profile extrusion process, 6061 aluminum is the first choice due to its reputation as the most commonly used industrial aluminum alloy and the most common extrusion alloy to date.
6061 Aluminum Alloy Composition
| Alloy | Si | Fe | Cu | Mn | Mg | Cr | Zn | Ti | Other | Al |
|---|---|---|---|---|---|---|---|---|---|---|
| 6061 | 0.4-0.8 | 0.7 | 0.15-0.4 | 0.15 | 0.8-1.2 | 0.04-0.35 | 0.25 | 0.15 | 0.05 | Remin |
6061 Aluminium Physical Property
| 6061 | |
|---|---|
| Density(g/cm3) | 2.73 |
| Coefficient of thermal expansion（μm/m·k）20~100℃ | 23.6 |
| Melting point range (℃) | 580~650 |
| Conductivity (% IACS) 20°C | 43 |
| Resistivity (Ω-mm2/m) | 0.040 |
What’s the Meaning of the T-word in aluminium alloy
Aluminium alloy groups, expressed as four digits, with different numbers indicating different alloy compositions.
For example, the main alloying element of Class 2 alloy is copper, the main alloying elements of Class 6 aluminium alloy are magnesium and silicon, and the main element of Class 7 aluminium alloy is zinc.
The heat treatment of aluminium alloys, on the other hand, is indicated by capital letters and numbers.
Capital letters, such as F, O, H, W, T, etc., indicate different types of heat treatment.
For example, 6061-T6: indicates that the aluminium alloy belongs to the 6th category of aluminium alloys, i.e. aluminium-magnesium-silicon aluminium alloys with solution heat treatment, and artificial ageing: T6.
T: Heat Treated (Thermal Treated, Heat Treated)
T denotes heat treatable, heat treated to produce a stable temper in addition to F, O or H.
T is the most widely used symbol for heat treatable alloys and can be used for any heat treatable alloy.
Heat treatable alloys are usually rapidly quenched after solution heat treatment, supplemented by natural or artificial aging.
T is always followed by one or more numbers to define the different treatments that follow.
Different T alloy temper description and application
| T Alloy Temp Item | Description | Application |
|---|---|---|
| T1 | After moulding at high temperatures and cooling, it is naturally aged to an essentially stable state. | Applied to room temperature aging products after a high temperature moulding (e.g. casting or extrusion) process at a cooling rate sufficient to increase strength. Applied to products that have been moulded at high temperatures and cooled without cold working, or where cold working, e.g. spreading or straightening, does not have a significant effect on the mechanical properties. |
| T2 | High temperature moulding and cooling, followed by cold working and natural ageing to steady state. | / |
| T3 | Solid solution heat treatment, followed by cold working and finally natural ageing to a stable state. | Applied to products where strength can be increased by cold working, e.g. spreading or straightening. |
| T4 | Solid solution heat treatment, followed by natural aging to a stable state. | Applied to products that have not been cold worked after solid solution heat treatment, or where cold working does not improve strength. |
| T5 | High temperature moulding and cooling, followed by artificial ageing. | Applied to products that are moulded at high temperatures (e.g. cast or extruded) and cooled, then artificially aged to improve mechanical strength and dimensional stability. |
| T6 | Solution heat treatment followed by artificial ageing | Applied to products that are not cold worked after solid solution heat treatment, or where cold working does not improve strength. |
| T7 | Solid solution heat treatment followed by aging in a furnace until stabilisation. | / |
| T8 | Solution heat treatment, followed by cold work hardening and finally artificial ageing | Applied to products where strength can be increased by cold working, e.g. spreading or straightening. |
| T9 | Solid solution heat treatment, followed by artificial age hardening and finally cold working to improve strength. | / |
| T10 | High temperature moulding is cooled and cold worked, followed by artificial ageing to achieve precipitation hardening. | / |
The commonly used 6061 alloy state
| Alloy | Temper | State |
|---|---|---|
| 6061 | O | annealed state |
| 6061 | T4 | After heat treatment in a solid melting furnace (quenching line), it is naturally stabilized to a basically stable state and is no longer cold processed. |
| 6061 | T6 | Solid solution heat treatment without cold working. |
| 6061 | T651 | Solid solution heat treatment followed by tensile process to eliminate internal stresses. |
Aluminum Alloy Mechanical Property of T4,T6 and T651
| Alloy/Temper | Yield Strength(Mpa) | Tensile Strength(Mpa) | Modulus of Elasticity |
|---|---|---|---|
| 6061 4 | 145 | 241 | 68.9 |
| 6061 T6 | 276 | 310 | 68.9 |
| 6061 T651 | 280 | 315 | 70 |
How to choose the 6061 alloy state between T4,T6 and T651
As discussed above, T6 means Solution treatment & artificial ageing, T651 means solution treatment & artificial ageing & quantitative stretching to eliminate internal stresses.
After the material has been processed by turning and milling, the workpiece is subjected to different clamping forces during processing, and it does not change under the action of external forces, but after the external forces are removed after processing, only internal stresses exist, and the internal stresses will drive the workpiece to elasticity, thus making the dimensions unstable. The internal stress of T6 will be relatively large, the processing will be deformed, the most suitable state for processing should be T651, he is based on T6 stretching, to eliminate internal stress.
Generally, if there is no precise requirement for dimensional stability and elastic margin, T6 is used; if precision parts are processed, T651 is used in order to avoid the elastic recovery after machining and thus dimensional instability.
The Difference of feature and application between 6061 T4 and T6
T6 is quenched after artificial aging, basically 6061 is more than 200 degrees to keep more than 4 hours, T4 is quenched after natural aging, put in the air in the middle of a period of time. Because the purpose of aging is to make the strength bigger, so the general price of T6 and strength will be higher than T4.
| 6061 T4 Feature | 6061 T4 Application | 6061 T6 Feature | 6061 T6 Applicaiton |
|---|---|---|---|
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Which industries and applications are suitable to choose 6061 T651
6061 T651 has excellent processing performance, excellent welding characteristics and plating, good corrosion resistance, high toughness and no deformation after processing, dense material without defects and easy to polish, easy to color film, excellent oxidation effect and other excellent features. 6061 T6 is the commonly used aluminum alloy state and 6061 t651 is the best characteristics of the 6 series of aluminum alloys.
6061-T651 representative applications include aerospace fixtures, electrical fixtures, communication fields, and are also widely used in automated machinery parts, precision machining, mould manufacturing, electronics and precision instruments, SMT, PC board solder carriers, and so on.
About Delin Aluminum
Delin Aluminum, a brand of AOYIN METALS, specializes in marine-grade aluminum plates with DNV, ABS, BV, and CCS certifications. We supply 5083, 5086, and 5052 aluminum sheets and plates for shipbuilding and offshore applications worldwide. Learn more about us →
