T4 vs T6: which aluminium temper should you order?
How each temper is made, how much strength it gives in each alloy and when to use one or the other.
In a nutshell
- T6 gives more strength: in 6063, 215 MPa tensile strength against 130 MPa in T4.
- T4: solution heat treated and naturally aged at room temperature. When the part has to be bent, curved or formed: it is the most ductile state. It can be aged afterwards to gain strength.
- T6: solution heat treated and artificially aged to maximum strength. For structural uses, demanding parts and machining. It is the strongest temper of the 6000 alloys.
- T4 is more ductile: 14% elongation against 8% in T6, better for bending or curving.
| Property | T4 | T6 |
|---|---|---|
| Process | Solution heat treated and naturally aged at room temperature. | Solution heat treated and artificially aged to maximum strength. |
| When to use it | When the part has to be bent, curved or formed: it is the most ductile state. It can be aged afterwards to gain strength. | For structural uses, demanding parts and machining. It is the strongest temper of the 6000 alloys. |
| 6060: tensile strength (Rm) | 120 MPa | 190 MPa |
| 6060: yield strength (Rp0.2) | 60 MPa | 150 MPa |
| 6060: elongation (A) | 16% | 8% |
| 6061: tensile strength (Rm) | 180 MPa | 260 MPa |
| 6061: yield strength (Rp0.2) | 110 MPa | 240 MPa |
| 6061: elongation (A) | 15% | 8% |
| 6063: tensile strength (Rm) | 130 MPa | 215 MPa |
| 6063: yield strength (Rp0.2) | 65 MPa | 170 MPa |
| 6063: elongation (A) | 14% | 8% |
| 6082: tensile strength (Rm) | 205 MPa | 290 MPa |
| 6082: yield strength (Rp0.2) | 110 MPa | 250 MPa |
| 6082: elongation (A) | 14% | 8% |
| 6005A: tensile strength (Rm) | 180 MPa | 270 MPa |
| 6005A: yield strength (Rp0.2) | 90 MPa | 225 MPa |
| 6005A: elongation (A) | 15% | 8% |
Minimums from the EN 755-2 standard for thin-walled profiles; they vary with the thickness and shape of the profile.
- Order T4When the part has to be bent, curved or formed: it is the most ductile state. It can be aged afterwards to gain strength.
- Order T6For structural uses, demanding parts and machining. It is the strongest temper of the 6000 alloys.
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Frequently asked questions
What is the difference between T4 and T6?
T4: solution heat treated and naturally aged at room temperature. T6: solution heat treated and artificially aged to maximum strength. T6 gives more strength: in 6063, 215 against 130 MPa.
When should I use T4?
When the part has to be bent, curved or formed: it is the most ductile state. It can be aged afterwards to gain strength.
When should I use T6?
For structural uses, demanding parts and machining. It is the strongest temper of the 6000 alloys.