Differences Between T6 and T73?
What is T6 temper?
The T6 temper process occurs in two phases, quenching and aging, bringing the 7075 aluminum alloy to its maximum strength possible. While T6 is the stronger, more rigid of the two heat treatments in the discussion, it tends to more vulnerable to stress cracking.
What is T73 temper?
By comparison, T73 has lower strength, more flexibility, and provides a better product in extended high-stress environments. To reach this state, the material is heat-treated and aged to T6, but then they continue aging it. By overaging the material into the T73, it loses some strength but increases in durability. It is also more corrosion resistant.
Toughness decreases along with temperature for aluminum 7075. And for this reason, T73 is better suited for extremely low-temperature applications such as cryogenics.
If you are looking for specific numbers and hard data, check out our Product Guide for 7075 aluminum.
Uses for Each Temper
7075 is the strongest of the aerospace grade aluminum alloys. The first airplane that used mass amounts of 7075 aluminum was the Mitsubishi A6M Zero. The fighter’s legendary maneuverability was largely due to the superior strength to weight ratio of 7075.
Both tempers are still used in airplanes, spacecraft, and other high strength applications. In these situations, T6 makes up the bulk of the parts. T73 is used for components that need to be more flexible or routinely undergo high and continual stress. The bases of aircraft wings are a prime example. Gears, valve parts, shafts, and landing gear are more commonly made from T73.
Here is a list of some other common uses:
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7075 T6 round bar is a popular tempered aluminum product due to its impressive strength properties.Shop 7075 T6 Round Bar