How Titanium Is Cut
Titanium does not come ready to be milled into a product. It takes four major processes to take titanium from its raw form to the final product. The basic steps that titanium undergoes are as follows: titanium is reduced into a porous form; the porous form melted into an ingot; and the ingot then converted into general mill products. When converted to general mill products, titanium ends up as billet, bars, plates, sheets, strips, or tubes. At this point, titanium is then cut and undergoes secondary fabrication.
Cutting titanium is not an easy task. Because it is a reactive metal, it changes its chemical properties when exposed to heat. Therefore, titanium is cut cold. In the video below, you can see a Cosen AH320 Horizontal Band Saw being used to cut a block of titanium. This is one of the more popular ways to cut titanium. There are other methods such as water jet cutting, another “cool” way to cut titanium, and plasma cutting. Here at Titanium Metal Supply, we use the band saw and plasma cutting method.
The blade that we use to cut our titanium blocks is a Lennox Ti-Master Band. It measures thirteen inches long and has a 2-3 tooth pattern. These blades are always carbide tipped. Ironically, carbide is made from either titanium carbide or tungsten carbide. When the blade is tipped with it, the teeth stay sharper much longer than other materials. The main body of the blade is made from steel and the teeth are tipped with the carbide. With proper maintenance, carbide tipped tools can keep a sharp edge ten to twenty times longer than steel tipped tools. The blades at Titanium Metal Supply can last anywhere from a minute to the entire work week, depending on the operator and their experience.
Some logistics about what you are seeing in the video: the speed of the blade is 156 feet per minute, the material setting knob is on 7, and the head decent rate is set at 1 (this is set slow for video purposes). With this configuration, we can cut up to 4 square inches per minute while maintaining optimum blade life. We aim to cut 4 square inches a minute on various different pieces of titanium. This block of titanium was 35 square inches and should take 9 minutes to cut; with the slower settings it took about 15 minutes. In order to cut this particular piece of titanium, we could turn the head decent rate up to 2.5-3.
When cutting a titanium block, a coolant is continuously being poured over the saw to keep the process cold. This coolant is Cut-Cool #500. This coolant is collected at the end of the cutting process, drained and then put back in the machine to run again. You may also notice the metal shavings that come off the titanium block. These shavings are collected and compiled in a Gaylord… a bulk sized container. Once a truck load of Gaylord containers has accumulated, they are sold back to the mills for reprocessing.
The block seen in the video is 6AL-4V Grade 5 titanium and measures approximately 5” by 7”. It is being cut for a customer that manufactures underwater robots. They use a lot of titanium as it submerges easily and is resistant to corrosion. Grade 5 is the strongest grade of titanium available. One of it’s many advantages is that Grade 5 titanium is heat treatable (something that commercially pure titanium is not). This grade combines the strength and corrosion resistance of pure titanium with the ability to be welded and fabricated easily.
At Titanium Metal Supply, we work 8 hours per day, Monday through Friday, cutting titanium for a variety of different fabrications. From the aerospace industry to lightweight sporting equipment, the first step is to cut the titanium to certain specifications. As you can see, it requires both experience and state of the art equipment.