Sorry for the off topic question but...
What is the difference between 7075 and 6061? Is it like stronger? Lighter?
More Dense?
No prob man, this should explain it pretty well.
Aluminum is typically combined with (alloyed with) other elements to improve upon its material properties. The alloying elements make up a small fraction of the material by weight (typically less than 10%) but they can have a significant impact on the strength, weldablity, corrosion resistance and expense of the material.
6061 Aluminum Alloy (AA 6061)
6061 aluminum is a family of aluminum alloys combining aluminum with magnesium (roughly 1.0% by weight) and silicon (roughly 0.5% by weight), sometimes mixed with a variety of other materials including iron, copper, chromium, zinc, manganese and titanium. 6061 is a strong an easily welded alloy frequently used for bike frames (as well as aircraft, boats and more).
All 6061 aluminum alloys have the same weight (density) and stiffness, but the strength of the alloy varies slightly with the specific alloying elements and the "temper" or heat treatment used to produce the material.
There are three common tempers of 6061 aluminum:
6061-O is a soft annealed alloy and is the weakest of the three common tempers. It is too weak to be of use for bike frame tubes.
6061-T4 is a heat treated, naturally aged alloy that is roughly twice as strong as 6061-O.
6061-T6 is a heat treated, artificially aged alloy that is roughly 2.5 times stronger than 6061-O. 6061-T6 aluminum alloy is probably the single most popular material used in modern bike frames, and is also used extensively in the manufacture of other components such as derailleurs, stems, cranks and handlebars.
7005 Aluminum Alloy (AA 7005)
7005 aluminum is a family of aluminum alloys combining aluminum with zinc (roughly 4.5% by weight), sometimes mixed with a variety of other materials including silicon, magnesium, iron, copper, chromium, manganese and titanium. 7005 is 10% stronger and a little more brittle than 6061 aluminum.
7005 occupies a curious market position relative to 6061 frames. Unlike 6061, 7005 does not require expensive heat treatment to be strong enough to use within a bike frame. However, a non-heat-treated 7005 frame requires more material to provide its strength. This means you can find cheap but relatively heavy frames made of non-heat-treated 7005 alloy. One can also create a very strong and light frame out of heat-treated 7005 aluminum, but this adds cost to the manufacturing process. This means you can find more expensive, but very light and strong 7005 frames as well. Hence depending on the heat treatment, 6061 aluminum is comparable to 7005 at both high and low price points, but 6061 occupies the middle part of the market in addition to competing well at the high and low end. 7005 aluminum is primarily found in low-end bikes (when not heat treated) or high-end bikes (when heat treated) but rarely in the middle.
7075 is the highest strength common alum alloy. Yield and ultimate strengths almost double of 6061. 7075 aluminum is an alloy, with zinc as the primary alloying element. It is strong, with a strength comparable to many steels, and has good fatigue strength and machinability, but has less resistance to corrosion than many other Al alloys. Its relatively high cost limits its use to applications where cheaper alloys are not suitable.
7075 aluminum alloy's composition roughly includes 5.6–6.1% zinc, 2.1–2.5% magnesium, 1.2–1.6% copper, and less than half a percent of silicon, iron, manganese, titanium, chromium, and other metals. It is produced in many tempers, some of which are 7075-O, 7075-T6, 7075-T651.
7075-O
Un-heat-treated 7075 (7075-O temper) has maximum tensile strength no more than 40,000 psi (276 MPa), and maximum yield strength no more than 21,000 psi (145 MPa). The material has an elongation (stretch before ultimate failure) of 9–10%.
7075-T6
T6 temper 7075 has an ultimate tensile strength of 74,000–78,000 psi (510–538 MPa) and yield strength of at least 63,000–69,000 psi (434–476 MPa). It has a failure elongation of 5–8%.[2]
7075-T651
T651 temper 7075 has an ultimate tensile strength of at least 67,000–78,000 psi (462–538 MPa) and yield strength of 54,000–67,000 psi (372–462 MPa). It has a failure elongation of 3–9%.
7075 is not considered a weldable aluminum but is great for machining and is an amazingly strong material.
These are just quick copy and pastes from different info i have laying around hopefully it clears things up a little for you without going to much in to the complex bullshit.
... i guess we should get back to chromoly scooter decks now, sorry. lol
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