7005 vs 6061aluminum

[ThePubSA]

(Not shure if there is any similiar topics on forum could not find any, so sorry if there is can add or move mine. ty admin )

 

 

Have had both types of alu's on bikes iv'e had , was just wondering whats the difference between the 2 , and is 1 better/worse then the other.

 

Also sum descusions on T6 and single, double, tripple butted etc..

 

Also any knowledge of other alu's eg.9000 series ( Trek's ZR9000 (zirconium) ) are also appreciated.

 

Find it kinda interesting so any comments welcome.. njoi

 

"Most of the quotes are from topic's on other forums."

 

-_ ALUMINUMS_-

 

"Are the types of aluminum created by the manufacturers or by other institutions that the bike companies simply use under licence? I know for example, that Klein, were famed for the way they used aluminum, but were the processes their own or someone elses?"

 

"It has always been my understanding that the frame builders work with tubing mfrs, the metal experts, to develop the alloys and perhaps the tubing shapes/cross section. Then the tubing mfrs, Reynolds, Columbia, etc. actually make the tubes for the frame makers. The making of the tubes to the appropriate shapes at the appropriate spots for the stresses involved is a science and near art unto itself. The whole tubing design/manufacture is a collaborative effort."

 

"Easton are a high-end maker of Al tubing for bikes. As well as a variety of stock shapes they draw custom tubes at thr request of builders. I think it was Serotta who started the trend for custom tubesets. Before that everyone used whatever Reynolds/Columbus/Tange produced.

 

http://www.eastonbike.com/tubesets_top.html

 

This is fairly typical of modern tube manufacturers in all materials."

 

"Primary aluminum is produced as ingots [large blocks] or rolls[light gauge] of sepcific alloys. Pure, unalloyed aluminum is a very uncommon commercial commodity. The companies that produce primary alumium are rather few -- Alcan, Alcoa and Kaiser leap to mind immediately -- principally because of the cost and economies of scale involved in producing aluminum from bauxite.

 

The primary manufacturers sell ingot and rolls to secondary manufacturers like Easton, Columbus, Tange, Dedaciai, etc. These guys extrude or draw the metal into specific tube shapes and sell them to bike manufacturers. In a sense, a fair amount of the Italian, American and Japanese aluminum is, in fact, Canadian in origin and Jamaican or Australian [the sources of Bauxite] before that.

 

The shape of the tubes is actually more important to the ride quality and durability of a bike than the actual alloy employed in their manufacture. It's conceivable that a manufacturer could make a 6061 tubeset that rides like a 7005 tubeset by manipulating tube shapes.

 

The key difference -- in terms of bikes -- between 6061 and 7005, however, is that it is easier to weld 6000-series aluminum, so it was the first aluminum widely used in bikes and the alloy most likely to turn up at the lower end."

 

"Very good, except that 6061 requires a very high temperature,expensive heattreatemnt after welding,almost to the melting point. 7005 requries very little the way of heattreatment , is less expensive and is more often found on less expensive bikes. Cdale is one of the few using 6061.....anyone who thinks they can tell the difference between ALLOYS in the finished product is kidding themselvdes. And< I think, contrary to what Mech said, 6061 uses the zinc and is the harder or less flexible. Not that it really matters."

 

"The 6000 series alloys are primarily made with Magnesium and Silicon. T6 means the material has been solution heat treated then artificialy aged without cold working(ie rolling or folding and pressing).

 

The 7000 series is alloyed with zinc and doesn't require the extensive heat treatment of the 6000 series.

 

The 7000 series came later than the 6000 series. It is now the most extensively used alloy due to its greater ease of manufacture.

 

Both materials can be found at the lower end and the upper end.

It depends more on the frame manufacturer as to the quality of design. Factors such as double butting, weld quality and tube shape come into play here and are being continually developed.

The best guide to quallity I should think is to look at who manufactures the tubing ie, columbus , reynolds etc. alongside the frame manufacturer ie Cannondale, Treck, Look, etc."

 

"Everything on the 6061 tubing and the 7005 tubing is very accurate, but after welding 7005 tubing it needs to "cure" about 30 days to get to full hardness. So you often find 7005 frames built overseas, since it has to be shipped and it eliminates the extra T6 step from the manufacturing process. The domestic frames are in the bike shops much sooner."

 

"I was also confused when trying to figure out which AL was better or found on high end bikes. Seems like 6061 and 7005 are both found on low and high end... so I guess its all a wash.

 

For a description of the terminology and a decoder ring:

 

http://www.bikepro.com/products/metals/alum.html

 

Its interesting to note that 9000 series has not been defined by the industry, so Trek's ZR9000 (zirconium) is simply the name of their home-grown AL mixture.

 

Also, there are probably different grades of 6061, etc. Some manufacturers may have better quality control or tolerances on the impurities, so I would guess that all 6061 is not equal.

 

You can also check out reynolds for comparisons and how tubing is made.

 

http://www.reynolds-cycle.com/internet/us/tech/ustech.htm"

 

-_BUTTING_-

 

"There are actually 2 definitions. I'll give you the one that is generally recognized by the bike industry...

 

Butting is where that ends of the tube are thicker than the center. In steel frames this saves weight and radically improves response. In aluminum, it just saves weight- if aluminum is allowed to flex it will eventually fail.

 

 

 

So, in general, double butting is where the ends of the tube are double the thickness of the center of the tube. Triple butting is where the butts are still double the thickness but the length of the butt is 3 times the diameter of the tube. Strangely enough, most butts are at LEAST 3 times the diameter of the tube, so the actual difference between the two could be... nothing.

Guys, I mentioned there were 2 definitions, I gave one. The definition you provided is the classic one that is rarely referred to now. This classic referral never held water insofar that many tubemakers (outside of Reynolds and Columbus) were unable to butt both ends of a tube who then referred to the thickness of the butt as "single" or "double" butting. Refer to technical info provided by bicycle frame makers such as Kinesis for a further explanation."

 

"Tubing manufacturers feel that a frame needs different amounts of reinforcement in different areas. So to optimize frame tubing now comes in five different butting arrangements: none, single, double, triple, and quadruple. A tube without a butt has constant wall thickness; it is called a straight gage tube. A single butted tube is thicker at one end; double butted tubes are thicker at both ends (each end of the same thickness); triple butted tubes have ends of unequal thickness; and quadruple butted tubes have ends and midsections of varying thickness. "

 

"Different welders claim what they call double butting to be butting a second time to make a more gradual transition within the tube to avoid a harsh overbutting.Certain makers butt the top and bottom of the tube where some butt more evenly.This is simply custom butting however they please.Sheldon 's site is great but no one knows everything and no one can tell a frame maker what to define or how.[unless it is a patented design]Yet they may try to and all are allowed to have an opinion.

A triple butted frame,be it tubes or stays butted,is for racing only in my opinion as hard rock scrapes or hits can cause the frame to fail."

 

"Basically:

single butted - one end butted

double butted - both ends butted

triple butted - both ends butted but to differnt thinknesses

quad butted - both ends butted with not 1 but 2 steps in thickness."

 

"simple answer--

 

--triple butted is lighter and more expensive than double"

 

-_T6_-

 

T6 (solutionized and artificially aged)

 

6061-O

Annealed 6061 (6061-O temper) has maximum tensile strength no more than 18,000 psi (125 MPa), and maximum yield strength no more than 8,000 psi (55 MPa). The material has elongation (stretch before ultimate failure) of 25-30 %.

 

 

6061-T4

T4 temper 6061 has an ultimate tensile strength of at least 30,000 psi (207 MPa) and yield strength of at least 16,000 psi (110 MPa). It has elongation of 16%.

 

 

6061-T6

T6 temper 6061 has an ultimate tensile strength of at least 42,000 psi (290 MPa) and yield strength of at least 35,000 psi (241 MPa). More typical values are 45,000 psi (310 MPa) and 40,000 psi (275 MPa), respectively.^[3] In thicknesses of 0.250 inch (6.35 mm) or less, it has elongation of 8% or more; in thicker sections, it has elongation of 10%. T651 temper has similar mechanical properties. The famous Pioneer plaque was made of this particular alloy. A material data sheet ^[4] defines the fatigue limit under cyclic load as 14,000 psi.

 

 

Welding

6061 is highly weldable, for example using tungsten inert gas welding (TIG) or metal inert gas welding (MIG). Typically, after welding, the properties near the weld are those of 6061-0, a loss of strength of around 80%. The material can be re-heat-treated to restore -T4 or -T6 temper for the whole piece. After welding the material can naturally age and restore some of its strength as well. Typical filler material is 4043 or 5356

 

 

Extrusions

6061 is an alloy used in the production of extrusions—long constant–cross-section structural shapes produced by pushing metal through a shaped die.

 

 

Forgings

6061 is an alloy that is suitable for hot forging. The billet is heated through an induction furnace and forged using a closed die process. Automotive parts, ATV parts, and industrial parts are just some of the uses as a forging.

 

To get to the -T6 temper, the 6061 is heated to about 990F, then quenched in water, then aged at about 350F for around 8 hours. That changes the typical yield strength from 8 ksi to about 40 ksi- fairly substantial.

 

But that quenching in water puts residual stresses in the aluminum, since there is a surface-to-center cooling gradient. The -T651 designation means the mill took that extrusion and gave it a 1% to 3% stretching, or permanent set, to get rid of some of those residual stresses. Now we can machine it and it shouldn't distort.

 

Finally, the final digit in the -T6511 designation (and how I know it was an extrusion, since this only applies to extruded stock) means that the mill is allowed to straighten the extruded bars, like in a press, to get them to meet the straightness tolerances.

 

[Witkop]

This question is irrelevant as we all know that alu is redundant. ALU is too harsh and rattles to much, also it has a poor life cycle.

 

The only material from frames is steel, and for the select few maybe Titanium. For the modern man (pastic) there is always carbon.

[MariusL]

This question is irrelevant as we all know that alu is redundant. ALU is too harsh and rattles to much, also it has a poor life cycle.

 

The only material from frames is steel, and for the select few maybe Titanium. For the modern man (pastic) there is always carbon.

 

What is this assumption based on?

 

My alu bike is lighter than most plastic bikes, mor responsive than the generic rebranded blank Taiwanese bikes... and oh so much better looking!

 

Two words: Cannondale CAAD!