types of aluminum

[RustyShackleford]

I've noticed at least 2 different types of aluminum, and I don't understand the differences. One type I've bought from McMaster-Carr and is identified as Type 6061 or Type 6063; it has a fairly dull surface sheen and is quite brittle when I've tried to bend a 1/8" thick piece into a right angle (it just breaks). I've bought another unidentified type at the scrap metal yard; it's fairly shiny and not nearly as brittle (a 1/8" thickness can be readily bent to 90 degrees). Any idea what this latter type is ?

 

[johneh]

https://www.metalsupermarkets.com/7-things-consider-choosing-aluminum-grade/

• (broken link removed) – Excellent Formability / Workability

• (broken link removed) – Good Formability / Workability

• (broken link removed) – Good Formability / Workability

• (broken link removed)– Excellent Formability / Workability

• (broken link removed) – Good Formability / Workability

• (broken link removed) – Good Formability / Workability

• (broken link removed)– Good Formability / Workability

• (broken link removed) – Poor Formability / Workability

• This will give you the information you are looking for

 

[Sawset]

What we see coming through here (sheetmetal job shop):
6061, high strength, usually no forming, cracking is an issue, structural members, jigs and fixture plates
5052, forming allowed, can crack if over stressed, less expensive, standard go to aluminum material
3003, forming allowed, resists cracking, better for anodizing, more expensive

 

[RustyShackleford]

Thanks guys. So apparently I just lucked into one of these "excellent formability" types at the scrap-metal yard. Lucky because I'm joining the end of a piece of angle to a flat plate, so I'm cutting a flap at the end of the angle and then bending it 90 degrees in a bench vise; I realize Im losing some strength that way, versus maybe using a separate little chunk of angle to make the attachment, but strength isn't an issue at all here.

Two questions:

1. The stuff from the junkyard that bends well is very noticeably shinier than the 6061 or 6063 from McMaster-Carr. The links above don't seem to mention shininess, or whatever the technical term for that would be. Can you give me any anecdotal info on that ?

2. All the types except 7075 say at least "good" formability. Is it unreasonable to expect "good" to allow bending 90 degrees (in a piece of material 1/8" thick) ?

 

[Dobish]

the shinyness really has to do with the surface finish on it, not really anything to do with the material itself. Sometimes it will also oxidize or have a chemical reaction with something around it.

I would expect that you will see some cracking with a bend in 1/8" aluminum, unless you are very careful about it. we mostly do billet, so bending is not really our thing.

 

[RustyShackleford]

the shinyness really has to do with the surface finish on it, not really anything to do with the material itself. Sometimes it will also oxidize or have a chemical reaction with something around it.

It's a REALLY pronounced difference.

I would expect that you will see some cracking with a bend in 1/8" aluminum, unless you are very careful about it. we mostly do billet, so bending is not really our thing.

Yeah, the 6061 stuff snapped right off before I got to 90 degrees; the shiny stuff didn't show any sign of doing so.

 

[Sawset]

We bend a lot of .125thk 5052 and 3003.
.04 bend rad
Usually no cracking.
.187thk, we'll use .125 bend rad and above.

 

[RustyShackleford]

We bend a lot of .125thk 5052 and 3003.
.04 bend rad
Usually no cracking.
.187thk, we'll use .125 bend rad and above.

Yeah, I'm simply sticking my .125" material in a bench vise and bending it. I wonder what bend radius that results in ? The material thickness, or double it ?

 

[KJamesJR]

You try heating it?

Little propane torch. Heat the area you want to bend, don’t quench it just let it air cool then try bending.

 

[zrock]

The shiny stuff you got from the salvage yard was probably off someones project and had been polished at some point. Usually alum does not come polished unless you specifically ask for it

 

[Gunfixr]

You know, bending over a bench vise jaw is probably the hardest on any material, as far as inducing stress that would cause cracks. The corner is sharp. Any radius at all will help, and larger radius will help more.
Bending and forming machines always have at least a minimal (. 030-.040") radius on the corner or nose that does the forming. You can find smaller, about 010-.015", for very thin steels.
If your project can stand a corner radius, it will work easier, and be stronger. Just put a steel rod, the length of the jaw, between the aluminum and jaw, where you will be wrapping the material around it.
Yes, it will be tricky trying to hold all that and get it all straight while tightening the vise.
1/8" rod will work, 1/4" would be better. The larger one will likely be a bit easier to hold.

 

[maple1]

Thanks guys. So apparently I just lucked into one of these "excellent formability" types at the scrap-metal yard. Lucky because I'm joining the end of a piece of angle to a flat plate, so I'm cutting a flap at the end of the angle and then bending it 90 degrees in a bench vise; I realize Im losing some strength that way, versus maybe using a separate little chunk of angle to make the attachment, but strength isn't an issue at all here.

Two questions:

1. The stuff from the junkyard that bends well is very noticeably shinier than the 6061 or 6063 from McMaster-Carr. The links above don't seem to mention shininess, or whatever the technical term for that would be. Can you give me any anecdotal info on that ?

2. All the types except 7075 say at least "good" formability. Is it unreasonable to expect "good" to allow bending 90 degrees (in a piece of material 1/8" thick) ?

How are you joining it?

 

[pjohnson]

Besides the alloy such as 2024 there is also a temper such as T6, T3 or O with O being very soft and bendable and then heat treat it to T3 or T6 depending on the strength you need. If you look close the metal also has a grain to it. It should bend better across the grain rather then with it.

 

[rowerwet]

Boeing uses 7075 to build aircraft. It's light and strong for fuel savings, but down the road the aircraft get ultrasonic inspection and all the cracks get patches and repairs.
Most small aircraft use 2024.

Brittleness is also dependent on the heat treatment, indicated by the T number after the alloy number

 

[Ashful]

Sheen is no indicator of hardness, I regularly polish 6061 to a mirror finish.

99% of machines aluminum widgets are 6061-T6. The 6063 about which you inquired is more often used for things like structural tubing.

BTW, there are cast aluminum products (ie jig plate) that are as brittle as ceramic.