1) Is titanium used in the automotive market? It is, although I see it used more in the aftermarket, racing, or high-performance segment of the automotive industry along with motorcycles versus typical automotive production. I see it in areas of high-output engines such as valvetrain components – valves, valve springs, valve spring retainers, rocker arms, wrist pins, and connecting rods. Titanium is also used for other racing applications where high strength and light weight are desired.
2) What are titanium’s advantages in high-performance automotive applications? Any time you can reduce weight without sacrificing strength, you are gaining performance. Performance can be improving miles per gallon, increasing payload capacity, or decreasing lap or run times in racing. There are reports showing for every 100 lb in weight reduction, you can improve mpg by 1% to 2%. In high-performance engine applications, the less rotating mass you have, the less parasitic loss you have to overcome, leaving more horsepower with which to race.
3) Is there a reason it’s not used more in general automotive production? High costs and sourcing challenges are the key deterrents. Titanium, compared to steel alloys, can be 20x more expensive per pound. Combine this with machining challenges, and the cost per component can get high. For example, I looked at a racing parts catalog and a set of eight, 4130 steel-alloy connecting rods was $250. A similar set of titanium connecting rods was $6,000.
4) What are the machining challenges? High density and modulus of elasticity make titanium desirable, but these features also make it challenging to machine. Titanium can be machined efficiently if correct cutting parameters and cutting-tool geometries are used. In general, you would machine titanium at 40% of what you would machine steels. Overly aggressive machining in steel has minimal consequences except to wear out your tooling faster. If you get too aggressive when machining titanium you can develop an oxide surface layer that can lead to part failure. It takes heat and pressure to generate a chip, so when the heat gets excessive, it can generate this oxide.
Great care in the machining process with coolant placement and cutting tool geometry are contributing factors in how much heat is generated. Higher positive rake angles and higher helix angles, such as the ones in our Z-Carb series of tools, reduce the necessary pressure to generate a chip, reducing the heat. It’s challenging to maintain sharp cutting edges that reduce the generated heat with proper cutting-edge strength to be as productive as possible.
5) Are there any opportunities for increased titanium use? Yes, the titanium industry looks for new opportunities in the automotive market, including exhaust, body panels, and suspension components. Cutting tool manufacturers continue to advance the tooling used to improve the productivity and reliability of machining titanium.
For more info: www.kyocera-sgstool.com