Bicycle frame ZR 9000 alloy

[rocketbracket]

Hi,
Any information/experience on proper filler rod to use for this alloy.
Thx.

[kize]

Hi,
Any information/experience on proper filler rod to use for this alloy.
Thx.

Quick search on the net--I find that zr 9000 alloy (that was heavily used by Klein) is just 7000 series aluminum that is hydro formed. So 7000 series filler applies. I'm no expert on it. I'm sure someone that's a metallurgist will chime in. Good luck.

[H80N]

Trek

Hi,
Any information/experience on proper filler rod to use for this alloy.
Thx.

Are you planning on repairing a TREK frame..??

you might consider contacting them as to filler and possible preheat and post weld heat treat that it requires. if any.

I found sales hype but nothing about the metallurgy of ZR9000
do not know if it is an actual proprietary Aluminum alloy or if it is simply a tradename (used by Klein/Trek Bicycles) of a more common alloy

ZR 9000 Alloy -- Trek's Advanced Concept Group spent over a decade developing a new generation of alloy. And their work has finally paid off. During those years, Trek engineers experimented with hundreds of alloy variations to discover a frame material that's light and fast riding. The whole character of an alloy is decided by its hardening agents. Creating alloys, engineers will strengthen it with Magnesium, Lithium, or Silicon in small quantities to harden it. But if you make the alloy too strong, it'll crack when you try to form it. Make it too light, and it'll dent. After twelve years of development, Trek engineers discovered the perfect amount of the hardening agent Zirconium to create a remarkable material for bike frames.
ZR 9000 Alloy is the first alloy developed exclusively for the bike industry. Why's that such a big deal? To make superior bike tubes, an alloy must be able to withstand the stresses and stains unique to cycling. The frame material has to be strong, but at the same time be dense, weldable, formable, and capable of heat treatment. This has been achieved by adding the hardening element Zirconium. This has allowed a tubing that is fast and strong enough to surpass the expectations of the riders of the Trek/VW mountain bike racing team. One of Trek's engineers said of ZR 9000 Alloy, "It's been fun to work with." ZR9000 Alloy is now available on seven road and mountain bike models (some made especially for women).

http://trekdg.com/brands/klein-bicycles-pg68.htm

http://totalbike.com/web/interbike/2001/trek_bicycles.html#zr9000

[elvis]

If it is a bike frame you might want to contact the mfg for a warranty replacement. I broken many trek frames and warrantied them out many times. I always got a Brand new product back.

[rocketbracket]

Hi,
Thank you all for all the info.
Yes Trek's Gary Fisher edition model Sugar.
I will try to contact Trek.
Doing repair for riding bud. I'll check with him about doing the warranty thing with Trek.
I will be testing 5356 on that rear shock bracket. I can always grind it down.
Thx

[H80N]

Hi,
Thank you all for all the info.
Yes Trek's Gary Fisher edition model Sugar.
I will try to contact Trek.
Doing repair for riding bud. I'll check with him about doing the warranty thing with Trek.
I will be testing 5356 on that rear shock bracket. I can always grind it down.
Thx

Ouch.... that looks like a design issue... stress concentration...

just welding it up will not fix the problem... likely crack right along side the new weld bead in short order...

[elvis]

Fwiw, I typically broke my frames around the read linkage. I think I rode harder than the engineers thought I would.

Good luck. That could be quite the challenge!

[Hobart Aluminum]

This is the best article that I've found on this alloy and it's written by the guy (Gary Klein) who developed alloy ZR9000.

https://dl.dropboxusercontent.com/u/87530746/Trek%20ZR%209000.pdf

Without knowing the exact chemistry it's impossible to know for sure what the best filler metal for welding one of these frames is, but he gives enough info where we can make a pretty educated guess.

Based on the article he started with 6061-T6 and tweaked the chemistry so its not a 7000 series alloy. He mentions that the frame is heat treated several times and I'm sure, for strength reasons, that it was post weld heat treated. There were only two filler metals available when this alloy was developed that were heat treatable: 4643 and 4145. 4145 is not recommended for welding 6XXX base metals so I suspect these frames were welded with 4643 (the earlier version of 4943 that was developed in 1963 by Bruce Anderson at Alcoa).

Alloy 4943 is going to give the the closest match to what was originally used (plus it will be slightly stronger). Keep in mind that if you don't PWHT&A the frame, that the HAZ of the weld (tube) will be even weaker than before and will probably crack again. That is because you are partially annealing and overaging the base metal in this region. I know that's bad news, sorry.

You mentioned that you might try to repair it with 5356. That is a possibility but you will still have problems in the HAZ plus its a bad idea to weld over 4XXX filler metal with 5356. The high mag content of the 5356 mixes with the high silicon of the 4XXX and gives you a highly crack sensitive weld.

[rocketbracket]

Good info. and article.
I will definitely buy a 1# of 4943 after reading that.

I tested with 5356 . it seemed to be "grabbing" it very nice w/o any cracks. After grinding weld down and giving it rough polishing it had nice penetration.
I will add some gussets in certain area. Will also proceed with PW heating and annealing.