Alloy grades - tell me about them!
- Thread starter Pickle
- Start date
http://en.wikipedia.org/wiki/Aluminium_alloys
As with all engineering material choices, there's no such thing as a bad material, only an inappropriate one.
As with all engineering material choices, there's no such thing as a bad material, only an inappropriate one.
shovelon
Senior Retro Guru
Both are good with the edge given to 6061. Both can be welded in the T6 condition, T6 being the stage of hardening.
6061 is used in boutique cycles, where 7005 is used mostly in production frames. 6061-t6 is easily formable, machinable, and weldable, but must be heat treated after the weld process because it has a very short annealing time. 7005-T6 has such a long anneal time that a weld can be introduced and cooled without a huge loss in Temper.
Both 6061 and 7005 are welded with high strength filler rod, such as 5356 or 5183. The weld nugget, under rapid cooling of the weld zone, if done correctly and to spec, will reharden.
7005 is an Easton formula, and is most exclusively lisenced to the big asian factories. The small boutique shops use 6061, but must heat treat after weld, so the manufacture is more expensive.
6061 is used in boutique cycles, where 7005 is used mostly in production frames. 6061-t6 is easily formable, machinable, and weldable, but must be heat treated after the weld process because it has a very short annealing time. 7005-T6 has such a long anneal time that a weld can be introduced and cooled without a huge loss in Temper.
Both 6061 and 7005 are welded with high strength filler rod, such as 5356 or 5183. The weld nugget, under rapid cooling of the weld zone, if done correctly and to spec, will reharden.
7005 is an Easton formula, and is most exclusively lisenced to the big asian factories. The small boutique shops use 6061, but must heat treat after weld, so the manufacture is more expensive.
An added benefit of the 6061 and other 6000 grade alloys is that it has very good resistance to several forms of corrosion and is excellent for weldability.
A benefit of 7000 series aluminium is that if properly treated they can achieve higher strength. Some seatposts in 7075 T6 have a "zing" to them not found in more pedestrian alloys. But it needs to be coated even in normal atmospheric condition to protect against corrosion.
I also seam to recall some 2014 series alloys used in stems and handlebars, IIRC 2014 is an alloy used in high strength stuctural forgings.
A benefit of 7000 series aluminium is that if properly treated they can achieve higher strength. Some seatposts in 7075 T6 have a "zing" to them not found in more pedestrian alloys. But it needs to be coated even in normal atmospheric condition to protect against corrosion.
I also seam to recall some 2014 series alloys used in stems and handlebars, IIRC 2014 is an alloy used in high strength stuctural forgings.
kanerdog1x1
Senior Retro Guru
its got something to do with seawater too hasnt it? 7000 series is mostly used in asia because it is easier to manufacture, and 6000 in the americas because of the different types of minerals in sea water?
shovelon
Senior Retro Guru
:shock: 7005 has a high degree of zinc as the key alloy. 6061 has magnesium as the key alloy. Both are cheap and plentyful.kanerdog1x1":2l9c06oz said:
The Asians strongarmed liscense agreements out of Easton. Combined with slave labor rates and Chinese government subsidies, they can process huge quantities to cover the whatever royalties. I suspect the Asians gave Easton an ultimatum that they will produce with or without an agreement. :twisted: So most the rest of the world is shut out of 7005, so we use the traditional non-liscensed 6061.
The only place to get 7005 at all is thru bike frameset trader like Nova Cycle supply, but the prices are more than you can buy complete bikes for in some cases. Hardly fair is it. :roll: 7005 alloy is only slightly more costly than 6061, like 5%. 6061-T6 runs about $2.15 US dollars right now, you can do the math. It is cheaper that cheap steel thanks to all the steel imported into China.
A lot of alum. bike builders here in the States built thier own heat treat facilities. Foes, Intense, Cannondale and so forth. Kind of energy intensive, but cheaper than farming out. Boeing in the USA has the heat treaters pretty busy right now, so prices are high. I would expect Airbus has the EU treaters quite busy.
Rant over.
shovelon
Senior Retro Guru
Pickle":2s73l6dw said:
I think scandium is a Russian developement. Scandium composite alloy is basically 6061 mixed with a binder like ceramic whisker. The scandium acts like the rock aggregate in concrete.
It is actually pretty easy to weld but you need to push the filler under the surface of the weld bead to fill the joint. Kind of like pushing a spoon thru mud instead of water, it just does not flow like you would expect. The filler is high strength rod or wire like 5356, or a special mix of scandium lace rod with 5356 as the base. Heat treat is the same as 6061.
Well that is the best I remember about Scandium and carbide composite.
and just to add to the kind of unanswered 2000 series alloy question- generally it has very poor weldability, meaning its ok for bars and stuff that aren't joined to things. .
and for reference, 9000 series alloy is undesignated (No ANSI pecification), so Kleins gradient 9000 is actually a wee engineering joke on us, tonge in cheek like. .
and for reference, 9000 series alloy is undesignated (No ANSI pecification), so Kleins gradient 9000 is actually a wee engineering joke on us, tonge in cheek like. .
