How do you bend Titanium sheet metal?

Kyle_in_Tex · Feb 23, 2015

I made my wife a cookie sheet out of some Ti6Al4v (grade 5) that I had laying around for years. I think it is about .035" thick. I put it on the brake we have at work and started bending. I wanted about a 1/2" lip on the long edge for strength and a place to grab with a pot holder. When it got close to 90 degrees, it started cracking and in a couple places, actually split in half. I ended up tig welding it back together at the bend.

Pretty expensive cookie sheet I know. But the most expensive part was sanding it down to a decent surface finish. I'd say it has a 16 finish or so.

Probably should've engraved my name and the date on it so when my children's children's children use it, they'll remember my name. LOL.

DuckSlayer1017 · Feb 23, 2015

I've always heard that it needed to be hot formed. Try heating it then putting it in the brake.

Kyle_in_Tex · Feb 23, 2015

Does anyone know how hot?

DuckSlayer1017 · Feb 23, 2015

I once toured a shop that did it. They had it red hot and then let it cool in the die so it wouldn't move. A quick Google search said 1200F.

Baby Grand · Feb 24, 2015

You do know that titanium will burn if heated hot enough in air, right?
Can be a very difficult fire to extinguish in a hurry.
The powder is especially "sparky", so be careful with any grinding or sawing.

http://titanium.com/wp-content/uploads/2010/10/Material-Safety-Data-Sheet.pdf

Some forming & general info:
Warm forming titanium parts - TheFabricator.com

Some more info:
Forming of the Titanium and Titanium Alloys: Part One :: Total Materia Article

I love the material - I have been wearing a fairly inexpensive titanium watch for the past 6 or 7 years that has a titanium case, back and wrist band. It's eerily light and has held up well to the abuse I've dished out to it.

Pepsiboy · Feb 24, 2015

Kyle,

having over 20 years experience in precision sheet metal, I would say that you are trying to bend it to sharp. Measure the thickness with a micrometer. Then use a forming die that has an INSIDE radius that is 3 times that thickness. Also, being it will be a baking sheet, I would not bend it more than 60 degrees. As you get close to 90 degrees, the stress on the OUTSIDE radius of the bend is VERY high. When I would be working with Titanium, I would do what is called a "Soft form" to get 90 degrees, NEVER a "Hard form" as the metal COULD fracture along the outside radius.

For the finish, I would use a dual action orbital sander with 120 grit pads, then go to 180 grit or 220 grit. After getting it very even finish with that, go to a 400 grit, then to 800 grit. Take your time and be patient with the finish. After using the 800 grit, I would TRY making a pad of 4-0 (0000 that is) of steel wool. Wash very well with mild soap and water, and dry. HOWEVER, Titanium SHOULD have a VERY smooth surface to start with. If your sheet DOES NOT, it probably is an inferior grade. What I have worked with was always labeled as "T-3". :2cents: Best of luck.

Dave

Kyle_in_Tex · Feb 24, 2015

Thanks guys. Great info.

Dr_Zinj · Feb 25, 2015

So much for my idea of turning titanium sheet metal into a nice set of armored plate.

Kyle_in_Tex · Feb 25, 2015

Pepsiboy said:
Kyle,

having over 20 years experience in precision sheet metal, I would say that you are trying to bend it to sharp. Measure the thickness with a micrometer. Then use a forming die that has an INSIDE radius that is 3 times that thickness. Also, being it will be a baking sheet, I would not bend it more than 60 degrees. As you get close to 90 degrees, the stress on the OUTSIDE radius of the bend is VERY high. When I would be working with Titanium, I would do what is called a "Soft form" to get 90 degrees, NEVER a "Hard form" as the metal COULD fracture along the outside radius.

For the finish, I would use a dual action orbital sander with 120 grit pads, then go to 180 grit or 220 grit. After getting it very even finish with that, go to a 400 grit, then to 800 grit. Take your time and be patient with the finish. After using the 800 grit, I would TRY making a pad of 4-0 (0000 that is) of steel wool. Wash very well with mild soap and water, and dry. HOWEVER, Titanium SHOULD have a VERY smooth surface to start with. If your sheet DOES NOT, it probably is an inferior grade. What I have worked with was always labeled as "T-3". :2cents: Best of luck.

Dave

I think the larger radius is the secret for us backyard benders. The heat would be difficult to do in a small time operation.

Kyle_in_Tex · Feb 25, 2015

Dr_Zinj said:
So much for my idea of turning titanium sheet metal into a nice set of armored plate.

What you really want is a suit of beryllium armor with kevlar undersuit.

MossRoad · Feb 25, 2015

What happened to the SR-71 Blackbirds after they were retired?

OkieDave · Feb 25, 2015

MossRoad said:
What happened to the SR-71 Blackbirds after they were retired?

View attachment 413978

Some are on display at various museums, others are at Davis-Monthan AFB.

MossRoad · Feb 25, 2015

OkieDave said:
Some are on display at various museums, others are at Davis-Monthan AFB.

The others are at Duncan Hines.

beeforty · Feb 26, 2015

Kyle_in_Tex said:
What you really want is a suit of beryllium armor with kevlar undersuit.

I'd rather have the titanium, much lighter weight and comes in sheet form. It is hard to drill through and form, DC10's used it as a thin skin doubler around door frames, making it hard to do doubler repairs in the cracked Aluminum cutouts. Never seen Beryllium in sheet, usually as a rod for making bushing/bearings. Very hard wear surface but it is nasty/toxic material to work with. They made tools out of it for working in highly explosive areas like mines and missile silos so if you drop a tool it won't spark. The Beryl co. was one maker of sockets I've seen. I have a claw hammer that was my wife's grandfathers who used to work as a carpenter in mines back in the 30's-40's. Looks like a brass hammer but a little more coppery looking.

Gary Fowler · Feb 26, 2015

Kyle_in_Tex said:
Does anyone know how hot?

I welded a lot of Titanium piping and it was a strict no-no to expose Titanium welds to atmospheric oxygen when above 500F IIRC. We had to have argon gas coverage on the weld when TIG welding it. We did this either in a argon purged Plexiglas container or by fabricating a trailer that was attached to the TIG torch and kept inert gas on the hot weld. Weld length was a little less than the length of the trailer and we had to stop and let it cool. If we removed it too quickly, the titanium weld would change from a bright silver to gold then blue. Light Gold was sometime OK but dark gold indicated a titanium oxide had formed which was extremely hard and the weld would have to be ground out and replaced. We could quickly check it with a very sharp pointed tungsten welding electrode. If we could scratch it with the tungsten, it was ok. If it got too much O2 before cooling, it was so hard that no amount of pressure on the tungsten would leave a mark.
For this reason, I think any heating and working of the metal would have to be in an inert atmosphere, otherwise it would just harden the surface and make it harder to bend.

Titanium oxide, I believe is what you get when you buy black titanium jewelry or even drill bits with gold titanium oxide finish, super hard surface finish that is very durable.

Dr_Zinj · Feb 26, 2015

I've seen beryllium in tube form. Makes some incredibly light and strong bicycle frames. But the cost is astronomical.

oldtimer 66 · Feb 26, 2015

When the SR-71 Blackbirds were built back in the late 50's that is when titanium was developed as a material. A lot of trial and error heat treatment gage size etc. There are lots of good articles on the planes development. They initially had trouble drilling the titanium and that is when cobalt (M42) drills were developed. Penn State developed the engine fuel/ hydraulic fluid. The hydraulic fluid needed to withstand 800 degree F and then was burnt as fuel.Now again as I generally do, this from memory, so if I made an error or two here, it's on me. It is well worth the time to read the history of the SR-71A. I think i still have a couple of VHS tapes on the planes developement. Later

MossRoad · Feb 26, 2015

oldtimer 66 said:
When the SR-71 Blackbirds were built back in the late 50's that is when titanium was developed as a material. A lot of trial and error heat treatment gage size etc. There are lots of good articles on the planes development. They initially had trouble drilling the titanium and that is when cobalt (M42) drills were developed. Penn State developed the engine fuel/ hydraulic fluid. The hydraulic fluid needed to withstand 800 degree F and then was burnt as fuel.Now again as I generally do, this from memory, so if I made an error or two here, it's on me. It is well worth the time to read the history of the SR-71A. I think i still have a couple of VHS tapes on the planes developement. Later

What I find most ironic is the titanium ore for that plane came from Russia. Gotcha, comrade! :laughing:

Kyle_in_Tex · Feb 27, 2015

beeforty said:
I'd rather have the titanium, much lighter weight and comes in sheet form. It is hard to drill through and form, DC10's used it as a thin skin doubler around door frames, making it hard to do doubler repairs in the cracked Aluminum cutouts. Never seen Beryllium in sheet, usually as a rod for making bushing/bearings. Very hard wear surface but it is nasty/toxic material to work with. They made tools out of it for working in highly explosive areas like mines and missile silos so if you drop a tool it won't spark. The Beryl co. was one maker of sockets I've seen. I have a claw hammer that was my wife's grandfathers who used to work as a carpenter in mines back in the 30's-40's. Looks like a brass hammer but a little more coppery looking.

Beryllium is less than half the weight of Titanium. And 50% greater modulus of elasticity than steel. True, you don't want to breathe in any dust or particles of it. You grandpaw's hammer is probably beryllium copper.

But it is so rare, they should rename it Unobtanium.