Cutting Titanium

[habu68]

my brother is a tool and die maker, and has some experience working TI heavy feeds and speeds are called for and he recommends never pausing or retracting a drill or mill until cut is finished, because the part will work harden as soon as the pressure is off.

a couple of other notes: One of the first uses of Ti in aircraft was the SR-71(habu) black bird and the learning curve was steep. Part failures were high until they discovered that the chlorine in the water was reacting with the Ti and causing stress cracks. Also trace amounts of chrome from chrome plated tools would cause TI bolts to fail. Part failure at Mach-3+ can be a real E-Ticket ride.

[Farmer Phil]

Hmm, maybe I should even speed up the saw a little more. I just went up from slow to medium. There's one more pulley I can move to. I have to stop cutting every ten minutes or so though. The 1/3 hp motor, as well as the block of Ti, get pretty hot. Anyway, that's some fascinating info. Thanks.

[DerekC]

Happy to see you were successful in your cut.

I worked 5-years in the Saw-Department of a Forge-Shop that produced rings and forgings for aerospace applications (up to 120-inches in diameter.)

Typically (as in almost always) we cut Titanium (6-4, CP, 6-2-4-2, 8-1-1, etc) with abrasive cut-off saws. I believe we did cut it with band-saws on very rare occasions like when the billet-diameter was oversize (greater than 12-inch diameter) too large for the abrasive saws.

We used wet-abrasive saws driven by 250 HP electric motors, so each cut was fairly quick (seconds to a bit over a minute.) There were "special-blend" abrasive blades used for cutting it (titanium) though our "General-Purpose" abrasive blades would work in a pinch, but not as well (straightness-of-cut and speed.)

As best I recall, when using a band saw, we had recommended feed-rates and speeds for the various grades of titanium, but it went slow and was hard on the blades.

After the saw-department, I worked in Inspection/Quality-Control a few more years, then several years more as supervisor in their Heat Treating department.

[Farmer Phil]

Wow, now that's some experiences with Ti! Wish I had some equipment like that, but alas, my cut off saw is as whimpy as my band saw. I cut off another slice though. Did it with the band saw, which is a small one, as it only can handle a 1/2" blade. Went through three bimetal blades to do it. I may have gottten a good deal on the Ti, but the cost of cutting is sure running up the tab. I worry for the little 1/3 hp motor on the saw too. After this knife project for my Dad, I'm not sure I'll be doing much with the stuff, simply because of lack of proper equipment resources.

[RegionalChaos]

Make a really thin hot cut and try hot cutting it!

I'f you've got some Ti laying around, how could you not try forging some tongs out of it!?

[Farmer Phil]

The piece thats left is about 2" x 4" by 4.5". I'm not sure how I'd even hang on to it to get it in and out of the forge, never mind whacking away at it with a hot cut until shearing through it. A pair of tongs would be cool though, that's for sure!

[DerekC]

Yes Phil, lots of experience cutting Titanium, Nickel, Cobalt, Chromium, Aircraft-Aluminum, Magnesium, Niobium, Molybdenum, Tool-steel, Stainless, etc.

Over in the Forge Shop, they would take scrap titanium and Forge some really fine 3-foot-long "Jimmy" or Pry-Bars for us to use in stacking billets and moving bars and rounds on the rolling-tables that fed the saws.

Titanium really puts out bright, white light from the sparks when cut with an abrasive saw, and it forms a tan oxide when removed from the furnace to cool.

Was wondering if you or anyone would know where might be a good source of titanium-scrap, that could be purchased by the general public?

I would really like to forge one of those light-weight jimmy-bars of my own some day.

[RegionalChaos]

Originally Posted by Farmer Phil

I'm not sure how I'd even hang on to it to get it in and out of the forge, never mind whacking away at it with a hot cut until shearing through it.

Why you make some tongs of course!

Some tongs and a nice handled, wide hot cut.. Then go to town!

[tompdw]

Do you have access to a plasma cutter?

[Farmer Phil]

Ha, I might try the tong wresting of titanium in the forge yet. Don't know of anyone with a plasma cutter, off hand. A while back there was a fella selling Ti to members of the bladeforums. There are quite a few folks selling the stuff on eBay.