6061-T651, with 0.8-1.2% magnesium and 0.4-0.8% silicon, is part of the 6000 series of aluminum alloys, known for good corrosion resistance, high strength, low weight, an attractive silver-gray appearance, good weldability, and good stain resistance. These characteristics make 6061-T651 a popular choice for industrial automation systems, where high strength and low weight enable rapid acceleration and movement, as well as for food processing equipment that requires low weight and stain resistance. 6061 can also be precision-machined into bicycle frames, camera lens mounts, decorative hardware, and much more.
T651 designates 6061 in its solution heat-treated, stress-relieved condition, and is used primarily on 6061 plate (greater than 1/4” thick) and some extruded rods. Unlike T6 aluminum, T651-treated aluminum is stretched to improve flatness and dimensional stability.
6061-T651 builds a corrosion-resistant oxide layer on the surface to protect against atmospheric attack, and holds up well in marine environments. However, it can be removed by strong acids and alkalis.
6061-T651 rod and plate are also weldable using both MiG and TiG processes, but they require some skill when handling their high thermal conductivity and low melting point.
Machinability for this grade is excellent, and high cutting speeds are possible. Additionally, when machining 6061-T651 plate, the reduction in residual stress allows very tight tolerances to be held. Surface finish is also good. In turning operations, 6061-T651 tends to generate long, stringy chips, so close attention to chip-breaking is essential.
| Property | Value | Notes |
|---|---|---|
| Material Type | 6000 series magnesium-silicon aluminum | UNS A96061 |
| Density | 2.7 g/cm3 | 0.1 lb/in3 |
| Melting Point | ~582-652 °C | ~ 1,080-1,205 °F |
| Hardness (Brinell) | ~95 | |
| Tensile Strength | ~310 MPa | ~45,000 psi |
| Yield Strength | ~276 MPa | ~40,000 psi |
| Elongation at Break | ~ 12-17 % | |
| Modulus of Elasticity | ~68.9 GPa | ~9.9 x 106 psi |
| Corrosion Resistance | Good in atmospheric and marine conditions | Poor resistance to strong acids and alkalis |
| Magnetism | No | |
| Heat Treatment | T651 | Solution heat treatment for precipitation hardening, followed by stretching and aging |
| Machinability | Very good | High speeds preferred, produces stringy chips when turned |
| Weldability | Good, GTAW preferred, GMAW possible | Strength is lost in the heat-affected zone |
| DFARS Compliance | No | Not qualified as a specialty steel under DFARS |
With decades of experience and strong mill relationships, we’re more than just a distributor—we’re your trusted partner. Let us help you find what others can’t.
