Hi everyone, I was asked to weld a titanium bike frame. But I have never welded titanium before, I use an ac/dc gen. Trailblazer w/high frequencey with low amps of about 40. I haven't seen the frame yet,
but I think it is about 0.040x1-1/2 in tube. I don't know what grade the titanium is? Givin this, what rod, gas, preheat, postheat, and amps,
etc. would be practicle, and is welding titanium like welding aluminum or
stainlless? help from anyone appreciated.
A large concern for you will be ensuring that the weld joint is adequately protected against oxidation during welding. If not, an otherwise good looking weld will crack in service due to the formation of the hard "alpha case" (which heat treatment does nothing to remove). The inside of the tube(s) must be thoroughly purged before and during welding. You must plan how to ensure absolute gas coverage of the weld pool, the weld filler, and the trailing region behind the weld pool. You cannot clean the base or filler metals too much, you must be very thorough about this. Obtaining some Ti tubes for practice seems to be suggested.
Hi, Bonniweldeor, thanks for the info on the Ti welding, the bike frame
owner was in a hurry to get it back to his son, I told him to take it to
someone setup to weld Ti. I'm a mobile welder and not setup for this.
James,
Find out the grade of Ti your working with and let us know. Also...
There are some pretty good threads here on the AWS boards. These threads have some excellent weblinks to vendors and articles from NASA, Naval Joining Center and others.
Click on the "search" function at the top of your page Type in keywords such as "Titanium" and "Alpha Case," also, make sure you type in 999 for the max age of posts so that you get postings from the last few years.
Here are a few links to threads posted in this forum that cover similar questions to yours.
http://aws.org/cgi-bin/mwf/topic_show.pl?id=4382#18837
http://aws.org/cgi-bin/mwf/topic_show.pl?id=4739#22118
http://aws.org/cgi-bin/mwf/topic_show.pl?id=4603#20373
Hi Lawerence, I told the owner of the Ti bike frame I was not set-up for this . I saw the frame, it had no tags or brand name on it, and
finding the grade of Ti, I couldn't. (question) is there a grade of Ti-
rod that is a kind of fix all like 7018 is for steel? (anyone?) thanks.
p.s. (for non critical work) that is.!!
CP (commercially pure) filler rod can be used to weld most Ti alloys. But you may be giving up strength. Usually better to use matching filler. Most manufacturers seem to use use 3AL2.5V tubing. But apparently some use CP2 tubing, typically joined by bonding. 6AL4V is used a lot for machined parts.
You don't consider a bicycle critical work? Or was that just for future reference?
I think you made the right decision. It is best not to take on a job like this without sufficient information and experience to do it right.
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