What Does the Name 6061 T6 Mean
In the designation 6061 T6, 6061 is the alloy number and T6 is the temper. 6061 belongs to the 6xxx series of aluminum alloys, which combines the benefits of the 4xxx and 5xxx series behavior in corrosion resistance, welding and anodizing. T6 stands for temper, referring to the stage of artificial aging following solution heat treatment; it suits products that cannot be cold worked after solution heat treatment, though they may be straightened and leveled without compromising mechanical qualities. T4, by contrast, indicates natural aging following solution heat treatment.
Chemical Composition and Standards
The typical composition of 6061 includes silicon 0.40 to 0.8 percent, iron up to 0.7 percent, copper 0.15 to 0.40 percent, manganese up to 0.15 percent, magnesium 0.8 to 1.2 percent, chromium 0.04 to 0.35 percent, zinc up to 0.25 percent, titanium up to 0.15 percent, with the remainder aluminum. Sheet and plate are commonly supplied to ASTM B209, GB/T 3880 and EN 485, in standard sizes such as 4 by 8 feet, 1219 by 2438 mm, 1250 by 2500 mm and 1500 by 3000 mm, with mill finish, unpolished, polished, black or bright surfaces.
Mechanical Properties of 6061 T6
Typical mechanical values for 6061 T6 sheet include an anti-tensile strength of about 290 MPa and elongation of about 10 percent, with surface hardness above 95 HB. The tensile strength is often quoted as about 310 MPa with yield strength near 275 MPa for plate. Compared with other tempers, 6061-T6 provides the highest strength of the common 6061 conditions and is widely used for aviation aluminum, industry molding, automatic mechanical components and dies.
T6 vs T651
T651 implies relief from internal tension. The temper designation adds an Arabic numeral to indicate a specific process that has significantly affected product characteristics: T651 indicates the material has been stress relieved by stretching after solution heat treatment. Because the internal stress has been removed, 6061-T651 will not distort when cut or machined, which is why it is preferred for precision machining, while T6 is used where the highest strength in the simplest heat-treated condition is sufficient.
Practical Supply Information
6061 T6 and T651 sheet are available in thicknesses up to about 400 mm for thick plate, with surfaces including mill finish, black and polished bright. Typical packaging uses strong hardwood pallets with protective film or paper interleaving, and plates are commonly produced to commercial tolerances. Applications include aircraft aluminum, industry molding, automatic mechanical components, carrying vessels and semiconductor device components. When comparing alloys, 6061-T6 hardness exceeds 95 HB while 7075-T651 exceeds 150 HB, which is why 7075 is about 60 percent stronger and preferred for aerospace parts.
FAQ
Q: What does T6 stand for in aluminum?
A: T6 is a temper designation meaning solution heat treatment followed by artificial aging, which gives the alloy peak strength.
Q: What is the difference between T6 and T651?
A: T651 adds a stress-relief stretching step after solution heat treatment, so the plate will not distort when cut or machined.
Q: What is the hardness of 6061-T6 sheet?
A: The surface hardness of 6061-T6 is above 95 HB.
Q: Which is stronger, 6061 or 7075?
A: 7075 is roughly 60 percent stronger, with hardness above 150 HB, which is why it is used in aerospace; 6061 suits automotive and general structural parts.
Q: What standards cover 6061 T6 sheet?
A: Common standards are ASTM B209, GB/T 3880 and EN 485, with standard sizes from 1219 by 2438 mm to 1500 by 3000 mm.
