Phil Dwyer

Cutting Titanium

Recommended Posts

Hi Friends,

Any of you folks work with titanium? I'm trying to cut a 1" slice off of a 2"x4"x6" chunk of Ti-6Al-4V. It is slooooooooow going! I'm probably 6+ hours into it and still have almost 1" to go. Anyone have any suggestions, or is this par for the course?

Thanks, Phil

8464.attach

Edited by Farmer Phil

Share this post


Link to post
Share on other sites

After using a few bandsaws, something tells me that block should NOT take 6 hours. You need to change the blade. Your blade is probably doing nothing more then friction cutting, not unlike cutting a wood 4x4 with a metal wire. Call up grizzly, msc/J&L, kbc, etc and ask one of their techs what blade you need for your saw for exotic metals. Trust me you will be glad you did. That block shouldn't take easy less then an hour to cut through.

Share this post


Link to post
Share on other sites

If you don't need a perfect surface, you can cut Ti with a cutting torch just like steel. You may want to use a little darker shade in you cutting glasses with Ti than for steel since the sparks are very bright white.

Share this post


Link to post
Share on other sites

inazuma, new Ti is SPENDY. That's my understanding anyway.. But.... If you are resourceful, you might be able to find some cheaper. What I heard was that Ti has to be sold with its papers certifying it's make up. If a steel yard looses the paperwork associated with the Ti, then they can't really sell it as new.

Share this post


Link to post
Share on other sites

i dont have trouble hot cutting titanium, it is very soft to forge at a full heat use a thin slitting tools i use two and change to a cool one after a few blows.the scale is a greenish shade and gets everywhere.

Share this post


Link to post
Share on other sites

If your Ti has any paladium in it the cost goes up drastically, paladium is more expensive than gold or platnium. Also, cutting with a torch...do it outside, makes a TON of smoke! To the original question, should only take a new blade.

Share this post


Link to post
Share on other sites

I have heard that titanium gets fairly gummy when worked. Is there any truth to this? Would this affect the type of blade selected? i.e., gummy metal would require a coarser blade to be used to avoid plugging up the teeth.

I have no idea as to the validity of this. It's just a thought that popped into my head while reading this thread. I would imagine there are members here that know the answers.

Share this post


Link to post
Share on other sites

I believe Ti work hardenes some blade steels do also That simply means if you are useing a hand or bandsaw and the pressure is to light or the teeth are dull the spot you are cutting hardens and resists cutting. If using a bandsaw see if the blade will cut mild steel like it used to. You may also want to google Chuck Bybee, known as the Ti man he sells a lot and may have a thought.

Share this post


Link to post
Share on other sites

Thanks for all the ideas fellas. I'm on my third blade. It's a bi-metal variable 10-14 TPI. Got it from McMasters. Their chart says use variable blade for titanium. They also say use 2-4 TPI for my size stock, but for my blade length (64.5") 10-14 TPI is the fewest teeth they have. My previous blades both snapped. (I'm still learning how to use a horizontal band saw. Think I got all the guide bearings set right now.) I'll cut some steel with the blade in there now to see if it still cuts. Wouldn't that be a hoot if it's just dull? Anyway, guess I'll try and track down some folks who know more and can make more blade specific suggestions.

I don't want to use a torch. I'd really bugger this thing up then. It's also a too hefty a chunk (2"x4"x6") for hot cutting (for me anyway).

I got it as scrap for $10 a pound. I understand retail goes for over $100 per lb.

Share this post


Link to post
Share on other sites

If Rich is right and the piece work hardened (and from what I've heard about titanium, he probably is), don't try to restart the cut in the same place. After you check your blade and replace it if it's dull (which I'd bet it is), flip the piece over in the vise and restart the cut from the back. Make sure you've got plenty of feed pressure at all times. You may want to consider placing the blade against the block before starting the saw, or even adding weights to increase the pressure. Once you reach the work-hardened area at the bottom of the original cut, it won't be supported by anything and hopefuly will rip out.

Share this post


Link to post
Share on other sites

Well, I haven't done any more research yet, but am about to go check the saw blade. I'll probably put another new one on and flip the piece over and see how it goes.

As for usage of titanium....

I'm making my Dad a set of hunters for Christmas. He's having his second hip replaced in a couple of weeks. I was thinking of using copper and brass for the hardware in his knives. But have decided to try to see what I can do with titanium (as in his new hips) for the fittings.

The pic below shows my start of his gift. The larger blade is 57 layers (random) of 1084 and 15N20 I made up at a friends, Indian George, with his press. The smaller blade is actually for my young son. (He's now a bit older than in my avatar. He just turned seven.) It's cable damascus with copper guard and butt cap. I still have to forge another small one out for my Dad from the 57 layer billet. The antler is from a buck Dad shot in 1959 when I was two years old. I've uploaded a photo of me and our dog, at the time, with it after hanging and freezing.

8474.attach

8475.attach

Edited by Farmer Phil

Share this post


Link to post
Share on other sites

I got the stuff cut. Seems I just had to be more aggressive. I moved the drive belt up to a faster speed and shimmed up the motor so the belt was tighter. I also loosened the counter weight spring to increase the saw feed pressure. Additionally, for more weight, I hung a large pair of tongs off the end of the saw. She sure ripped (figuratively speaking) after that.

Thanks for the compliments on the blades Doug. You might want to hold them until the project is finished, as there's no telling how they'll come out.

All the best, Phil

8481.attach

Share this post


Link to post
Share on other sites
Thanks for all the ideas fellas. I'm on my third blade. It's a bi-metal variable 10-14 TPI. Got it from McMasters. Their chart says use variable blade for titanium. They also say use 2-4 TPI for my size stock, but for my blade length (64.5") 10-14 TPI is the fewest teeth they have. My previous blades both snapped. (I'm still learning how to use a horizontal band saw. Think I got all the guide bearings set right now.) I'll cut some steel with the blade in there now to see if it still cuts. Wouldn't that be a hoot if it's just dull? Anyway, guess I'll try and track down some folks who know more and can make more blade specific suggestions.

I don't want to use a torch. I'd really bugger this thing up then. It's also a too hefty a chunk (2"x4"x6") for hot cutting (for me anyway).

I got it as scrap for $10 a pound. I understand retail goes for over $100 per lb.


Phil, no offence to mccmaster-carr but you should call up J&L industrial and ask to speak to one of their experienced machinists/tech's and describe them your saw and your process. Seriously, you will be glad you did. I used to live by a J&L in chicago, there were impeccable with answering machining questions like this. Chances are you are not using the right blade/lubrication/power/speed requirement. Cutting billet Titanium is an advanced process and if it is taking 6 hrs to cut through that billet your blade is most likely work hardening the material as it is cutting. :( Titanium also has a springy quality which can result in oscilation during cutting and end up with rather light cuts and a byproduct of excess heat. You may even notice that your cut on your saw is not that clean of a cut due to the inefficiencies in your cutting method.


Check out this link and then i would try J&L or even KBC and talk to an experienced machinist.

Cool Tips for Cutting Titanium


Cheers,
Av

Share this post


Link to post
Share on other sites

Thanks for the tips Av. I did phone MSC/J&L up. The fella I spoke with said I'm pretty limited by my saw. There aren't many options for 1/2" wide blades. They do have a bimetal one that has a few less TPI though. Of course, its twice as expensive as the bimetal blades I got from McMasters Carr. Now I just need a few more bucks in order to place an order. In the mean time, I'll keep mucking along. And, see what others might carry.

Edited by Farmer Phil

Share this post


Link to post
Share on other sites

Phil
Glad to hear you got through the billet, While its not pertinant to this conversation I thought I might mention how I cut titanium in case you get in some thin .100 thick Ti that needs cutting.
I turn the blade backwards on my woodcutting bandsaw and friction cut with it. I can usually cut about 1 inch a second and mostly cut straight lines, sounds crazy but works very well.
Chris

Share this post


Link to post
Share on other sites

That's a good tip Chris. I've cut a fair amount of corrugated roofing in a similar way with a circular saw blade turned backwards in my worm drive. Noisy as xxxx, but it works.

Share this post


Link to post
Share on other sites

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.:o

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

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.

Edited by DerekC
correct minor error and add text

Share this post


Link to post
Share on other sites

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.

Share this post


Link to post
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.