What does the number in " 6061 aluminum " mean ?

The alloy. If it's 6061-T(something) then the end numbers specify the heat treat.

Take a look at

for details on specific alloys (dunno where you'd go for an overview, but searching on "aluminum alloys" might help).

Like Tim said, 6061 refers to the specific alloy. It is often followed by something like T-4 or T-6 which has to do with the heat treatment. It is all explained pretty well at:

From "Alloy and Temper Designation Systems for Aluminum"

1xxx 99%+ aluminum 2xxx copper 3xxx manganese 4xxx silicon 5xxx magnesium 6xxx magnesium & silicon 7xxx zinc 8xxx other 9xxx unused

The first digit refers to the major alloy group. In the 2xxx thru 8xxx alloys, the last three digits are assigned arbitrarily to identify specific alloys.

Ned Simmons

What the other guys said for the short answer. For the REALLY LONG answer, download a copy of the "METALLIC MATERIALS AND ELEMENTS FOR AEROSPACE VEHICLE STRUCTURES"

All 1700 pages of it. Shows all the comm> What does it mean when I see something like " lot of 6061 aluminum tubes" ?

9xxx will be used for transparent aluminum.

Gunner

"A prudent man foresees the difficulties ahead and prepares for them; the simpleton goes blindly on and suffers the consequences."

- Proverbs 22:3

Thanks for all of the GREAT info! How would I refer to the number if I were ordering some 6061 aluminum ? Call it "alloy number" ? "alloy mixture" ?

Or they'll just hand you whatever 6061 they have in stock, and it'll range from really hard* to really soft.

• I'm not sure of what the range of hardness there is available in 6061, because I've only got experience with 6061-T6. T6 is the most common, and if you just ask for 6061 and get it that's most likely what you'll get -- but you can't be sure.

At most places if you say "6061" you will get some T6 or T651, better places will ask if you want som "T0"

The hardness differences you see is more likely T6 that has been sitt> RoyJ wrote:

LOL

Just thinking off the top of the head - no expert opinion - The rack stuff likely went through a number of thermal cycles. Since Al is softer than the typical steel we work with - it might have had an internal migration of alloy rather flowing in a sense. Something like glass.

Martin

Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

RoyJ wrote:

Does this count?

The Air Force Research Laboratory's materials and manufacturing directorate is testing aluminum oxynitride -- ALONtm -- as a replacement for the traditional multi-layered glass transparencies now used in existing ground and air armored vehicles.

And Scotty was just a bit early for the mouse/microphone: SteveA

Actually Scotty was late.

In the late or middle 60's - Sandia announced the transparent Al - for windows in bathrooms and elsewhere. They discovered it and advanced it to a product. Others have licensed it and gone from there. Sandia is a National Laboratory of the U.S.A. I used to service the account as a Senior Scientist while with Schlumberger. It was some place.

Still is.

Martin Martin Eastburn @ home at Lions' Lair with our computer lionslair at consolidated dot net NRA LOH & Endowment Member NRA Second Amendment Task Force Charter Founder

Steve A wrote:

multi-layered glass

replying to pogo, Steven wrote: The first digit is the alloy type second digit is the modification of the alloy and the last two digits are the purity of the aluminum so 6061 means that in this case magnesium and silicon were added to the aluminum and that it was not modified and it is 61 percent pure aluminum

Bullshit , look it up . 6061 is approx 95% aluminum .

This patent for solution heat treating mentions the composition of the aluminum alloy originally called 61S, before aluminum alloy designations were extended to 4 digits.

To be pedantic, the ASM standard specifies "Al 95.8% - 98.6%", although the percentages of alloying elements are often specified and then "Remainder (or Balance) - Al".

Wish I had my scanner ready, lots of data. Terry is Correct.

6061 consists of : 0.4-0.8 Si, 0.7 Fe, 0.15-0.40 Cu, 0.15 Mn, 0.8-1.2 Mg, 0.04-0.35 Cr, 0.25 Zn,0.15 Ti, total variance .05 ea and 0.15 total all. Rest is Al.

Mostly AL.

Now there are special versions of 6061 that are called 6061/Si-C/47f which is the AA-registered alloy 6061 reinforced with 47% vol of continuous Si-C fibers. A special version indeed.

The Mg and Mn indicate work hardening alloy. Mixing Cu or Cu-Mg or Mg-Si or Zn-Mg Zn-Mg-Cu - age hardening.

Metals Handbook, second edition, Desk Edition, 75 Anniversary ASM Handbooks.

Mart> Steven wrote:

The first number is the primary alloying element or combination of elements (6 indicates the magnesium/silicon alloy group). Except for the 1xxx series, the second number refers to a possible modification of an earlier alloy of the same group. This "modification" can be a variety of things, but often refers to a change in the limits of alloying element percentages or llimits of impurities. One example is

7075 vs. 7175. The latter has the same basic alloying elements, but somewhat lower levels of silicon and iron. It's better for forging than 7075.

The last two digits are purely arbitrary for all but the 1xxx series. In the 1xxx series, the last two numbers indicate the percentage of aluminum, which, in this case, generally means the level of purity of aluminum.