Some Pros and Cons to Consider About Titanium Tubing
Because we at Metal Cutting are specialists in precision cut-to-length metal tube, people often pick our brains to learn more about the advantages or disadvantages of different tubing materials.
Titanium tube is an interesting topic because it’s a material that offers some unique benefits but also poses some distinct challenges. Even so, titanium is used in some medical devices and other applications where its unique characteristics are beneficial.
1. Desirable Attributes of Titanium Tube
Titanium tube is often used because of its superior chemical resistance, which is well above that of stainless steel grade 304 or even grade 316.
As a high-strength, low-weight material with high corrosion resistance, titanium provides a high strength-to-weight ratio that makes it a good choice for a diverse range of tubing applications. For example, Metal Cutting makes a variety of parts from titanium, including:
- Small diameter radiused tubes for use in automotive applications
- Small, round titanium tubes used for seed casings in brachytherapy.
- Thin wall titanium tubing for the casings of chemically active containers used in life sciences
Titanium tubes are also useful in analytical instruments, such as for chromatography and other applications where the tubing must:
- Resist repeated exposure
- Not interact with many different types of chemicals and other substances
Another advantage of titanium tube in medical devices is that it is biocompatible. Not only can the human body tolerate the use of titanium (which is important enough), but it is also nonmagnetic — an increasingly important trait as the use of magnetic resonance imaging (MRI) becomes more common in medical diagnostics.
From a temporarily placed cardiac needle to a (hopefully) permanent bone joint replacement, MRI compatibility is important for any medical device that is inserted or implanted in the body for any length of time and where a slightly magnetic material would be dangerous.
Otherwise, what is supposed to be a non-invasive diagnostic test could cause a metal device to be ripped from the body. Needless to that, that is NOT a good outcome!
2. Remarkable Variety of Grades and Recipes for Titanium Tubes
Another great thing about titanium is that, just as there are different types of stainless steel, there are many different grades of titanium tube.
For instance, ASTM has a variety of standards (principally B265, B348, and B381) relating to the “recipes” for titanium grades used in different applications. If you look at the specs, you will see there are even multiple grades for unalloyed titanium.
The most common commercially available titanium alloy, grade 5, offers high strength and toughness. And unlike pure titanium, grade 5 titanium is heat treatable, allowing it to be welded and fabricated for tubing and other uses in aerospace, marine, chemical, and medical applications.
3. Titanium Tubing with Shape Memory
For applications requiring shape memory, you might also consider titanium tube available in the form of nickel titanium, or NiTi (also called nitinol), which is its own, separate category of product.
While in theory the material is a 50/50 blend of nickel and titanium, NiTi is never exactly that. In fact, NiTi is always a custom blend, having no ASTM specification and with each manufacturer having its own unique, proprietary formula.
NiTi is often used to produce medical tubing that requires a high degree of flexibility and kink resistance, such as catheter guidewires, stents, and super-elastic needles for microsurgery. When properly treated, the material also offers excellent corrosion resistance.
4. Challenges of Working with Titanium
Of course, no material is all things to all applications, and titanium is no exception.
Comparison with Stainless Steel
One of the difficulties is that the material is somewhat more brittle and more difficult to draw than stainless steel. This makes titanium harder to work with.
Although titanium can be drawn into a tube, the process does not produce the nice smooth surface that can result when drawing stainless steel. There are companies that can draw titanium down to Ra 8-10 microinch; however, stainless steel can be drawn to a substantially smoother Ra 3-4 microinch or better.
The rougher ID on titanium tube can have an impact on the microfluidic properties of any liquid that needs to move through the tubing. This may be an issue in applications where the smooth flow of the liquid is especially important.
For most medical device applications, where the tube will carry blood and other bodily fluids, this is not a concern. However, turbulence is a serious problem in applications where the tubing must carry tiny fluid volumes.
Machinability of Titanium Tube
Being a more brittle and less forgiving material, titanium is also harder to machine. The more you have to do to titanium to achieve your final product, the greater the chances you can have a problem with chipping and other surface roughness issues.
The machining of titanium also requires more coolant than other materials may need. High-pressure coolant must be delivered at precisely the place of machining from multiple nozzles and angles, to flood the area with coolant.
In addition, titanium is rarely used for the junctures of tubes. In fact, for medical devices in particular — where a lot of machining is required to create flares, swages, and threading at the points of connection — metal of any kind is a very small part of the tube fittings market.
Instead, tube fittings for medical devices more often use high durability PEEK (polyether ether ketone) or other specialized plastics that can be molded and machined more easily.
5. The Cost of Titanium Tube
Across both the pros and the cons, the cost of titanium tubing must also be considered.
Historically, because titanium is not used as frequently as a material such as stainless steel, there are only a few smaller vendors that make titanium tube. Additionally, it comes in fewer standard sizes, requiring greater lead time to produce custom sizing, which in turn also adds to the cost.
Therefore, titanium tube is a material you’d better be sure you REALLY need — not something to be chosen lightly — if you are going to specify it.
Here’s an added tip: From a practicality standpoint when titanium is needed for a final product, companies often prototype the product design in another, less expensive metal to test the feasibility and function. If the initial testing validates the design, it can then be retested using titanium.
With such a remarkable variety of titanium tube options, it is vitally important to always specify which particular type and grade you want — whether it is pure titanium, one of the many alloys, or a NiTi formula — to optimize the manufacturability of your product.
(Learn more about Optimizing for Manufacturability in Small Parts Sourcing.)
6. Experts in Cutting Titanium Tube
If it IS the appropriate material for your specific tubing application, you can be confident that Metal Cutting knows how to cut titanium. In fact, we can cut, machine, or finish whatever type and grade of titanium tube you might need.
We routinely cut, grind, lap, and polish tubes in lengths as short as 0.006″ (0.152 mm) with wall thicknesses as thin or IDs as small as 0.001″ (0.025 mm) — in any metal, including titanium. (We like to say that if the diameter can be drawn, we can work with it.)
We can also cut coated tubing precisely without damaging the coating and while maintaining concentricity and a clean ID. In addition to titanium cutting, we can customize tubes with features such as angle cuts, slots, points, and holes.
To discuss titanium tube or other materials for your application needs, just give us a call. You can also learn more about medical device machining and metal tubing in our free, downloadable white paper Medical Tubing in the 21st Century: Who Needs It?