ZR9000 Alloy (Treks Frame Material) Help

Date 02-17-2006 16:33

Hello moltinmaster, short of taking a sample and sending it off to a lab for testing there is no easy precise method for identification. Tensile testing would probably give you an idea as to strength, but it is most likely a heat-treated frame so this wouldn't necessarily help you identify it as to composition. A number of the different bike frame builders use annealed aluminum alloys for the initial fabrication of their products and then they straighten and heat-treat them upon completion. If you are looking for a really good reference for aluminum materials and their weldability there is a book called " Welding Alcoa Aluminum", it was first copyrighted in 1954 and the latest copyright that I am aware of is listed as 1972. Check on the internet with Amazon.com for it or there is a technical book store in Portland, Ore. that sells new and used books called Powell Technical Book Store that may have a copy of it. I believe they also have an internet site that you could look for it on. Short of knowing the alloy specifically and being able to match the filler specifically I would consider repairing it with 5356 alloy. Just my 2 cents. Best of luck and regards, aevald

By Lawrence (*****)

Date 02-17-2006 17:52

Moltin,

I hope you read Aevald's post thoroughly paying particular note to his observation that most aluminum bike frames are heat treated after initial fabrication.

When a repair is performed on a heat treated aluminum alloy, the result will always be an somewhat softened weld and heat affected zone.

When you consider that the target area was subjected to high stress to the point that a material failure occured in the strengthened material, it leads to questions of the viability of a repair area that will be weakened by welding unless you have post weld heat treatment facilities.

Not saying you can't weld it. But if you do discover your frame is heat treated aluminum it is something additional to consider.

Edit:
Here is a link to an "Easton" manual for welding bike frames of both 6061 and 7005. They mention many of the small "craftsmanship" details one would expect when doing critical welds. Check it out.
http://www.eastonbike.com/downloadable_files/fab_instr/fab_instructions-7005_6061.pdf

Even more interesting stuff
http://www.mtbr.com/files/data/250.html

http://www.eastonbike.com/downloadable_files/r&d_files/R&D-03%20Scandium.pdf

By moltinmaster Date 02-20-2006 14:11

Thanks guys. I got some info frome one of the people at Trek. They said that it is not recomended to perform the repair because of the heat treatment, but that if I absolutley had to repair the frame they would send a piece of rod. I told him yes just to see what it was like.

P.S. It has to be welded in a inert atmosphere(must have Mag in it or something) Thanks for all of the replies.___

By Lawrence (*****)

Date 02-20-2006 15:16

If your frame requires an inert atmosphere above the normal GTAW normally used on bike frames I suspect that the thing may be Titanium.

A simple spark test will give you the truth on this.

Trek does produce some Ti frames... If you find this is the case its a whole new game.