oxygen,hydrogen,nitrogen in titanium 1

[joecontrol]

I am working on a heat treat furnace and i need to know at what temperature rage does,Oxyegn,hydrogen and nitrogen start to get infused into the titanium?

We and the customer and I are not sure if we want to build and indirect fired or direct fired furnace. I have seen heat treating for titanium done both ways. Their is a large cost difference in the designs.
thanks,joe

 

[EdStainless]

How large are the parts?
What steps are done after heat treatment?
Do you care about surface damage?
What Ti alloys are you working with?

You can pull up thermodynamic data for this, but basically anything higher than about 200F and you will have detectable reactions with O, C, N, H, S and so on. The real question is what can you tolerate.

Unless these are large thick parts that will get extensive surface machining afterward I would never look at direct fired for Ti. Way too many risks.

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Plymouth Tube

 

[TVP]

I agree with Ed--direct-fired furnaces really are not appropriate. Most heat treating of titanium is being moved to inert atmosphere or vacuum furnaces due to the contamination problems associated with H, O, etc. SAE AMS 2801 Heat Treatment of Titanium Alloy Parts is a good reference on this subject and a requirement if the parts are for aerospace applications. It even has a table that shows how much material needs to be removed if the parts are not heat in a vacuum or inert atmosphere.

 

[calphad]

Some basic information regarding the influence of elements such as oxygen, nitrogen, and hydrogen (among other alloying elements) on titanium and its alloys can be found toward the end on the following web page:

http://www.calphad.com/titanium-aluminum.html

Alojz Kajinic, Ph.D.

 

[metengr]

calphad;
Interesting web site.