Tech in GCC: Heat treatment of Titanium 6Al4v?

[sammyg]

I machined 2 rings from Ti6Al4V recently,they came out rather nice if I say so myself. Where do I go from here? Seeing that I after boring and tapering the ID, I finished the OD with a file, sand paper, scotch brite and leather, it seems this stuff is relatively easy to scratch.

Would heat treating the rings help this? If I'm not mistaken, Titanium doesn't get hard after heat treating, rather heat treating is used for annealing or stress relief. Would the heat treatment help the surface durability? I know it will get a nice color, which isn't that important seeing as how I think they look good raw.

If it would help maintain surface finish, what heat/time/quench should I follow? The metallurgy class I was in for welding wasn't clean on how to heat treat metals, what solutions to use (I would be doing it in air), any of that. I have googled it.
Thanks

[sammyg]

Anyone from the mid day Saturday crew have any ideas?

[Roc Doc]

Sorry I don't have any real metallurgy to offer, but I know that when they make bike frames from that alloy, they either polish it or brush it, and that both are fairly easy to scratch. The Rockwell harness is only 36, so it's gonna polish easy, and scratch easy.

[Triaged]

It isn't quench and temper like steel but solution and age. You need to find out what condition you got your material in. You need to do it in an argon atmosphere for the solution treat. What you might want to look up is "alpha-case". A bit of alpha case on your ring might get the surface hardness that you want...however everyone is most concerned with eliminating it not making it happen on purpose so info might be sparse.

[brianZ71]

You can anodize it, but im pretty sure it will change the coloring/look of it.

[usmcdoc14]

Originally Posted by brianZ71

You can anodize it, but im pretty sure it will change the coloring/look of it.

only if he added a dye. he could clear anodize and have no issues.

I am not sure on the tempering requirements

[reddman]

Originally Posted by sammyg

I machined 2 rings from Ti6Al4V recently,they came out rather nice if I say so myself. Where do I go from here? Seeing that I after boring and tapering the ID, I finished the OD with a file, sand paper, scotch brite and leather, it seems this stuff is relatively easy to scratch.

Would heat treating the rings help this? If I'm not mistaken, Titanium doesn't get hard after heat treating, rather heat treating is used for annealing or stress relief. Would the heat treatment help the surface durability? I know it will get a nice color, which isn't that important seeing as how I think they look good raw.

If it would help maintain surface finish, what heat/time/quench should I follow? The metallurgy class I was in for welding wasn't clean on how to heat treat metals, what solutions to use (I would be doing it in air), any of that. I have googled it.
Thanks

My understanding of Ti heat treatment is the same as yours, it can increase the strength of the material, but the hardness remains pretty much the same across the board, typically in the range of Rc35 plus or minus a few.

Titanium reacts violently with oxygen at it's heat treating temperatures. If you don't have the equipment to keep it in a 100% Argon environment in the heat treat oven you would likely be creating a bomb by putting Ti in an oven. It's a close relative of Magnesium.

There are some cool coatings out there that are as hard or harder than sapphire. TiN is gold colored, but personally I hate gold, so I would look at:

TiAlCN is dark purple to black.

ZrN is a tan color.

I have a 6Al4V Titanuim plate on my keychain, based on the one in my spine. I made it just over ten years ago, and initially tried to keep it's mirror polish, but it just won't stay on Ti. This is it's current sheen after a decade of beating against my keys:

[johnmcd]

This has the same wear as my wedding ring of 10 years next month. I do concrete construction and wear it daily, it does show lots of hazing scratches but nothing deep or that you can feel.

[brianZ71]

Originally Posted by usmcdoc14

only if he added a dye. he could clear anodize and have no issues.

I am not sure on the tempering requirements

From a quick google search it looks like titanium pretty much always changes colors with anodizing depending on the voltage used. I've never anodized any titanium, but I remember someone at work telling me about that when we quoted some anodized TI parts.

Wikipedia quote, so take it with a grain of salt:

Anodizing titanium generates an array of different colors without dyes, for which it is sometimes used in art, costume jewelry, body piercing jewelry and wedding rings. The color formed is dependent on the thickness of the oxide (which is determined by the anodizing voltage); it is caused by the interference of light reflecting off the oxide surface with light traveling through it and reflecting off the underlying metal surface. Titanium nitride coatings can also be formed, which have a brown or golden color and have the same wear and corrosion benefits as anodization.