In the 90’s we bought our Titanium tubing from a mill in Detroit called Ancotech.
We flew to Detroit and took a tour of Ancotech back in the day, and learned a lot about how titanium tubing is produced.
Helfrich was quite schooled on the subject (and by schooled we mean
self-taught), and worked with Ancotech getting the processes down that
resulted in our double-butted titanium tubeset. This was real honest to
goodness butting too, internally butted with a 2:1 wall thickness
differential between the fat ends and skinny middle. And it was very
expensive to do.
We’ll share a bunch of pictures with you that will show a little bit of the process. But first, we’re going to bring you up to speed on the process that happens before the small ingots get to the mill and are made into tubes.
Scot and Gary Helfrich wrote this together with much of the info coming from Gary (who has been known on occasion to embellish), but for the most part verified by our contacts at Ancotech. It’s been reprinted in various places over the last 15 years.
WHERE DOES IT COME FROM??
Titanium is the 4th most abundant metallic element found, after Aluminum, Magnesium, and Iron. A common source of titanium is Rutile Ore, consisting of TIO2, which is found in abundance all over the world - including some parts of Arkansas. Rutile is an accessory mineral commonly associated with igneous rocks. The word is from the Latin Rutilis, red, in reference to the deep red color often observed when light is transmitted through it. The other mineral commonly used to extract Titanium is Ilmenite, FeTiO3.
Now that we've found the metal in the ore, the fun begins. The most common method of separation is the Kroll process, which uses Magnesium (or sometimes Sodium) as a reducing agent.
There are two distinct steps in the production of metallic Titanium. First, Titanium dioxide (which by the way is the pigment often found in white paint) is mixed with coke or tar, then charged in a chlorinator. This is a real nasty process and should not be performed in the presence of the Sierra Club. The mix of TiO2 and coke is heated up and superheated chlorine gas is passed through the charge in the furnace. The ore reacts with the chlorine to form Titanium tetrachloride or "tickle" and the oxygen in the ore reacts with the carbon in the coke which forms carbon monoxide. This is vented off the atmosphere, and a pool of colorless liquid, the "tickle" remains in the bottom of the container. This liquid is then purified through fractional distillation. The highly refined tickle is mixed with powdered magnesium and the resulting sludge is put in a sealed container that is purged with Argon. The whole thing is heated up until it is glowing red and the magnesium has reacted with all the chlorine, leaving Magnesium chloride (a salt) and deposits of pure Titanium that look like sponge. This is called the titanium sponge.
At this point, the briquetting and alloying is done. The sponge is compressed by huge hydraulic presses into chunks of Titanium that are quaintly called "compacts," and then TIG welded end to end to actually form the consumable electrode that is described in the next paragraph. Aluminum and Vanadium are added at this time to make the alloy, for bicycles usually 3% Aluminum, 2.5% Vanadium or 6% Aluminum, 4% Vanadium. The weight of this "Melt" is about 15 tons, which is peanuts compared to Aluminum and Steel melts. For example, Bethlehem steel used to melt 1,700 tons at a time.
Part two is where you better hope there is a power station near by. After the sponge is compacted into huge electrodes, it is shoved into a consumable electrode vacuum arc furnace. What this means is that a chunk of Titanium up to three feet in diameter, and weighing 15 tons is shorted across the output of the Bonneville Dam. The resulting reaction is rather violent. This process is repeated up to three times to purify the ingot. The molten pool of Titanium is then allowed to freeze in the furnace, and stripped out along with the copper lining of the furnace. The lining is then ripped off the ingot. Machinists like the next step where this 15 ton ingot is chucked up on a rather large lathe and the titanium that is contaminated with Copper is turned off the outer layer. This should not be attempted on your Craftsman jewelers lathe.
Now we have an alloyed titanium bar weighing 15 tons that needs to get smaller. This is where a GFM machine comes in handy. This tool is a huge forge that defines the word gnarly. We are talking about raw horsepower here. The GFM machine pounds a 30" diameter ingot of pure Titanium down to as small as a 6" bar. They hammer on it, pound it and anneal it, slam it, batter it and anneal it, then they do it some more, until it gets down to the size desired for the breach of the impact extrusion machine.
The impact extruding machine makes the bar stock into the tubing. Imagine if you will the force required to convert solid 6" diameter bar of Titanium into a tube 1.5" in diameter. Not a little at a time, either. This happens in one pass, where a hydraulic cylinder as big as a whale shoves this bar into one end of the machine with tens of thousands of tons of force and out the other end spits a white hot tube about 25' long. The photo to the left shows the red hot ingot of Titanium about ready to be impact extruded. BOOM!
Before you imact extrude the titanium, you need to heat it to near its melting point. Titanium doesn’t melt until it gets extremely hot—about 2,800F—so heating it is a challenge. Someone figured out you could heat it pretty darn hot (as you can see in these photos) with a magnetic induction oven. These four shots show various parts of this process. Oven 0 shows the ingots pre and post heat. And if you look closely at that picture, you can see that “Joe was here”.
Then you take some salad tongs and grab a piece of metal that's been heated to more the 2,000º F. Those are little billets of Titanium about to get heated down at the bottom of the picture.
Then you carry the nearly molten metal over to the press that you see up at the start of our imact extruding section and put it in the jaws.
If you are thinking, big deal, read on. This white hot tube comes out with an undesireable layer called an alpha layer, so these wizards do the only respectable thing, they throw it (red hot) into a big vat of Hydrochloric Acid. Not any dilute solution, either. It's more like the liquid that came out of the monster in Aliens, which ate through everything in sight including the hull of the Titanium spaceship.
To the left you can see the red hot newly extruded titanium tube, fresh out of the extruder, ready to get dipped in acid.
And here are the long tanks of Hydrochloric Acid ready for red hot metal. You can see some tubes hanging from that small overhead crane.
There are two common tubing sizes made by this impact extrusion. One is about 2.375" in diameter and is used to make all the tubes over about .8". The 1.74" tube makes tubes smaller than this. These raw tubes are then sent to a mill where yet another studly machine gets used to make the Titanium tubes we all know and love.
There are some particularly fun aspects to the process described above. While Titanium is molten, it is highly reactive. As you probably realize from viewing Titanium products, usually there is no paint applied. That's because it doesn't rust, tarnish or corrode. At low temperatures, below its melting point of about 2800ºF, Titanium doesn't react with much of anything, which is why it is used heavily in the chemical industry. It's even more "stainless" than stainless steel. In its molten state, it's like a bomb. When the ingot decides to take a holiday away from the furnace and visit the atmosphere, the route is via a water cooling jacket surrounding the furnace. When water comes in contact with molten Titanium an explosion results. Back in the '60's before they really had this process figured out, Teledyne managed to level quite a few acres of their plant by this process.
Titanium, like magnesium, burns in air and Titanium is the only element that burns in nitrogen. When we have parties one of the rituals is to set a large pile of Titanium on fire, then try to douse it with a hose. The water provides lots of Oxygen to really supercharge the burn, then when the Hydrogen comes off after the disassociation, you get a mini Hindenburg. The O2 is floating around trying to decide who to have a party with, the burning H or the burning Ti. Don't try this at home, kids.
The thing to remember here, is that this is a nasty process that involves lots of chemicals and carbon monoxide being released into the atmosphere. After you buy your Titanium frame, doo dad or thingamajig, you better park your car for a week and ride your bike everywhere to get your green karma back in balance.
by Gary Helfrich and Scot Nicol
The Rest of the Tour of Ancotech
Your tour guide, Gary Helfrich
Also visiting Ancotech at the same time, Rob Vandermark and Ted Costantino, both from Merlin at the time. Rob went on to found Seven Bicycles, and Ted is an editor at VeloNews.
Mark Norstad of Paragon Machine Works showing a small billet and the resultant extruded tubes, before they're 'rockered' into smaller sizes.
We can't remember the name of this contraption but you can see the titanium tube running by the rollers fo the machine and getting super bent. It's actually a tube straightening machine that works some kind of magic. Tubes actually get straightened by getting bent.
This is not as gross as it looks. It's a rocker machine that carefully and gently reduces diameter and wall thickness. The gross looking stuff is lubricant.
The Russians were big into Titanium. So you see the influences all over the place. One of the coolest things we saw was a Russian Titanium garden shovel, 'for the gardener who has everything'.
Lots of testing happens before the tubing goes out the door.
A long surface plate, for making sure those long pieces of tubing are straight.
Special bonus, we snuck around back
That is a lot of Nitric Acid. There were also tanks of Hydrochloric Acid.
It is what it says it is.
Our weld standards were very high, and welders had to practice a lot before we let them lay their beads down on a product that was going to be sold. We managed to get some 'scrap' out of Anco for welding practices. And no, none of this ever made it into saleable products. They were real strict on that.
FINAL INTERESTING TIDBITS
While in Detroit, we went to a Titanium trade show. Sound fun? At the trade show, we did get to see Gary wear a shirt with a collar, so that was a first. We also saw this car, a 1955 Firebird II.
Yes, the experimental concept car's body was made from titanium. GM's brochure from the 1956 Motorama auto show referred to titanium as the 'wonder metal'. GM stylist Harley Earl received patent 180509 for his design, which resembles a jet fighter on four wheels. The concept car never went into production, however GM's Pontiac division later adopted the Firebird name for their very popular muscle car. Here are a couple of better pictures, poached from the internet.
That is about it for today's detour. Bonus points for anyone who can tell us what the ANCO in Ancotech stands for. Anyone?