Aluminium Grades

what are the best types of aluminium for turning and what are the differences between the different grades?

That is probably the wrong question - you need to ask "what material properties does the part need" and then find the most suitable grade for machining. There are more grades of aluminium than bits of string!

Mark

That can be a BIG question, but to summarise:

There are three common alloys available in bar stock, 6063-T6, 6082-T6 and 2014-T6 (alternatives to 2014 are 2017 and 2024 all in T6)

6063-T6 = soft, decorative not too strong, I've found it a bit sticky on my carbide tools. Weldable. Yield strength similar to EN1a, but breaks not much later

6082-T6 = medium strength, general purpose, turns quite well. Weldable if that's useful. Yield strength similar to structural steel, breaks not much later. Probably most easily available.

2014-T6 - strong, expensive, hard to get & turns well. Not really weldable. Breaking strength similar to structural steel, yield strength higher than structural steel.

Regards,

Richard.

Edited By richardandtracy on 16/01/2017 14:25:37

Hi Curtis,

Aluminium grades are explained several places on the net, here's a couple of links:

***Link***

***Link***

Alloys like 2007, 2011 and 6020 are easy to machine, use sharp tools and more top rake than you would use on steel. I have mainly machined Al Mg alloys and have had few problems.

Thor

You will also find that some of the ME suppliers still use the old code numbers for aluminium.

6082 is HE30 a good general purpose one that will do for most model uses

2014 is HE15 keep this for things like engine conrods wher strength and wear resistance are needed as it costs quite a bit more than 6082

You're right, most the parts I'm looking to make as a beginner won't need anything more then being able to turn and of a reasonable strength, my first project is going to be a fire piston so sounds like 6082-T6 is sufficient. Many thanks all

Edited By Curtis Rutter on 16/01/2017 14:47:42

T6 is fantastic, machines like butter, great huge chips come off it and the finish is marvellous.

The price reflects it's value. The T in T6 stands for temper.

Michael W

Curtis

I have found 2011 Free cutting to be the easiest to machine, it comes off in chips just like cast iron but I don't know the qualities.

I find 6082T6 (HE30) machines well but if not careful with toolshape, speed and feed rate can be stringy as if the chipbreaker is not working, despite this it is my most used aluminium. Link below is a  DCMT070202 cutting 6082T6

Emgee

https://youtu.be/wzNLvM9q2Dk

Edited By Emgee on 16/01/2017 14:57:55

One more for the 'useful' list ... 'though not usually thought-of for turning:

Alcoa MIC-6 cast tooling plate

[similar products from different manufacturers have different numbers]

This is flat, stable, and very easily machined.

MichaelG.

I agree with the initial comment on knowing what the part is for, and then selecting an appropriate material. Material selection is about the most important initial step in any job, and in terms of value, a good choice can make a decent job, while a poor choice makes it difficult to get a decent finish, or sufficient strength, etc.

I also agree that grade 6082/HE30 has good machining properties, as does the tooling plate.

I believe the 7000 series grades have better machining characteristics, and are significantly stronger, but at much greater cost. The tooling plate, which I use from time to time, machines nicely, but unless you specifically need guaranteed flat plate, the cost would be hard to justify, as it is very expensive.

So 6082 is the best compromise for the everyday jobs, in my book.

The results depend on speeds and feeds, as with almost any material. Running with a broad cut of 38mm, 0.5mm deep at 500mm/minute is fairly spectacular on a small mill, but although the finish is not bad, machining dry with a carbide cutter designed for aluminium is likely to produce thin hairy slivers which will attempt to weld themselves back onto the job. Running a little slower or less deep gives a finish like chrome plating.

Marcus

.

Marcus,

I accept that can be expensive, and difficult to source, but:

Careful shopping got me this "off-cut" from a reputable dealer ...

They shipped it 'internally' from their Glasgow branch, and I collected it [bubble-wrapped] from Manchester.

Price: £24 + VAT ... which seems very reasonable to me.

MichaelG.

Good price!

I use 450 x 450 x 16mm which costs £120 (inc VAT) for one piece. Shocking really; but someone else pays for it and I machine it (in fear and trepidation in case I muck it up). It is not supplied through a metal dealer, but a company who take the machined plate and use it as a mould plate, hence the particular size. I suspect the 3rd party being involved in the supply accounts for the substantial markup.

If your supplier is the company I think it might be, I have great trouble getting a firm quote from them, despite my close proximity, so I usually order other aluminium in large sizes from a company in Yorkshire who send it up here at surprisingly low cost. Two way traffic, or what...

Marcus

I use quite a bit (for me) of 7075 T651 tooling plate on my motors. Ian S C

I tend to trust the suppliers what ever material it is. For instance if I want aluminium i just ask for that. If I need some specific characteristic I mention it. It doesn't take much imagination to guess what grade the term aluminium is likely to produce. Same with many materials.

The reason goes back a while. I might spend some time looking for a suitable spec and then have trouble finding it. The dealer usually stock materials on the basis of what they are likely to sell. Sometimes even hold stock for specific customers. So if I wanted some aluminium for con rods I might finish up with one of these 7000 series that has been mentioned. I might also ask what grade the stuff is on something like that. I might be told that there are 2 grades one being more expensive than the other and even be told the differences. I find they are generally helpful. I did get caught out once because I used a supplier that provided materials for the company I worked for and as a joke some one arranged for me to get something different to what I asked for. I've never gone back there again.

Maybe not good enough for a business but fine for some one like me.

John

-

Im machining a lump of 6" dia 6082T6 at the moment, absolute joy to turn. I get all mine from the Aluminium Warehouse online - 3 grades to choose from.

Stress corrosion is a significant problem with 7075, general advice in industry is not to use it unless you have to.

I've had to specify a certain amount of 7075-T6511 in the last few years because of the strength I needed for a given weight, making a lifting beam to be supplied with each box. Our aerospace customer had to go through a massive approval & testing regime to accept it (75k of life cycle testing) - all prompted by their experience of bits falling apart in the sky. Some of the non-sequential tests ended up with very degraded performance, but it was just about OK.

This year the company I work for is making about 450 tons of aluminium boxes, almost all of that weight is 6082-T6. Much fewer problems with the stuff than the fancier alloys.

Regards,

Richard.

The last con rod I made for a small IC motor (1 1/4" bore x 1 1/2:" stroke) was made with an aluminium alloy bicycle pedal crank.

Ian S C