Stress Relieving 6al-4v Titanium

RUGUR

RUGUR

Joined
Jun 4, 2005
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I would like to learn more about stress relieving 6al-4v titanium. Please share your techniques and experiences. What works for you?

I find it to be very time consuming to flatten titanium in preparation for making folding knives. But I recently heard that I can get a big head start on flattening by "stress relieving" my titanium in a heat-treat oven first. Apparently, the titanium will flatten out some during the stress relieving process.
The instructions I have found for stress relieving 6al-4v titanium have all been very different from each other. I'm interested to hear what really works for other knifemakers.

When I flatten materials, I lap them on my surface plate and I check the flatness with a precision straight edge.
 
Any input would be helpful please. I want to know if this procedure has worked for anyone else and I would like help deciding on a specific course of action for stress relieving my own 6al-4v Ti. What times and temperatures will give me the best results? Can I perform this operation in a Paragon HT oven or is there some problem that I have not thought of yet?

Here are some of the instructions I found:

Dynamet
Mill Anneal: 705-790°C for 1-4 hours, air cool (or equivalent)
Solution Treat + Age (STA): 940-970°C 10 min., water quench (or equivalent) plus 480-595°C for 2-8 hours, air cool (or equivalent)
Stress Relief: 480-650°C for 1-4 hours, air cool (or equivalent)

http://www.titanium.com/titanium/tech_manual/tech6.cfm
900 - 1200F, 1 - 4 hr., AC

http://www.key-to-metals.com/Article97.htm
2 h at 540°C (1000°F)
 
Rob,i've had fairly good luck with doing the following:

I profile out me handles,then use arbour press to straighten as close to flat as i can.Much easier to straighten thin strips then large pieces.i then lay out my handle pattern,drill in skeleton holes.after you remove all this steel its far easier to bend the TI around

I'm also able to do all my critical drilling as i use my drill set up on my mill,where i can clamp parts down so they are 100% flat.if handles are'nt flat when drilling this could obviously cause issues but on your drill press if you use strong clamps you'll be ok.

I'd like to know how to flatten large pieces,but there does'nt seem to be much info out there?i tried heating it in the oven and press quenching it,but it does'nt seem to react the way steel does,it still has heavy springyness.
 
I haven't found a specific answer to my original question. One experienced knifemaker told me that he didn't think a standard HT oven could get up to the temperatures required to make titanium flatten out. I don't have my own HT oven yet so I will have to wait to experiment.

I found a different solution. I'm going to send my titanium out for "double disc grinding" service. Double disc grinding will make the titanium precisely flat and parallel. It's a little bit expensive, but it will be worthwhile because it will save me time and it may be more accurate than if I do it myself. I like to do all the work myself but I'm going to get some help in this case.
I had heard of double disc grinding before but I didn't understand how it works untill now.
 
I'd rather not create a new thread when this one asks my question. Which of these methods work best? I just received 25 "flat" 1"x5"x1/16" blanks, and they are mostly warped because the guy sheared one side and used a wheel to cut the other.

If no one says otherwise, I'm gonna try 1000f for 1hr then air quench in my 1" plates to try to flatten them.
 
Yes, from a guy in MI. About half are really nice, clean, sheared, and flat. The other half are warped and look as if they were cut with a dremel.
 
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