Alternate Gear Material
Alternate Gear Material
(OP)
I had a request to make a gear set lighter. My colleague asked about using Titanium alloy. I need 166ksi UTS material with a wear resistant surface. Is this strength obtainable with titanium? Can I make its surface wear resistant via some modification treatment (nitriding, anodize, PVD, etc)? What about an aluminum alloy?





RE: Alternate Gear Material
Thread330-110611
RE: Alternate Gear Material
RE: Alternate Gear Material
The current state of technology really does exist for creating robust titanium alloy gears. Titanium alloys can be processed to your recommended strength level, and they can be treated by diffusion processes involving oxygen or nitrogen for surface hardening, but these processes do not create the fatigue resistant surface that carburizing does for steel. Your best bet for reducing gear weight is to increase the surface stress on a steel design, and make the steel design very strong. This can be done by using the best steel grades (low inclusions, high temper resistance), optimal heat treating parameters that create the best microstructures (no intergranular oxidation, no non-martensitic transformation products, optimized carbide structures & retained austenite, etc.), shot peening to create residual compressive surface stresses, and some type of finishing treatment to reduce surface roughness, such as the isotropic finishing done by REM. The following links have some excellent information on this subject:
http://www.grc.nasa.gov/WWW/5900/5950/Research.htm
http:
Also, you should contact Carburize to discuss this project, as he is intimately involved in gears and gear heat treating.
RE: Alternate Gear Material
TVP: Is this really feasible with the optimized steel design you speak of?
Also, thanks for the links. I will definitely check them out over the holidays. Cheers.
RE: Alternate Gear Material
I have seen some gears that use Ti for a hub and spyder, and use high strength tool steel for the rim & teeth. With PM tool steels a lot is possible.
= = = = = = = = = = = = = = = = = = = =
Corrosion never sleeps, but it can be managed.
http://www.trenttube.com/Trent/tech_form.htm
RE: Alternate Gear Material
Holes and reduced hub section are two points.
RE: Alternate Gear Material
RE: Alternate Gear Material
The last three responses from EdStainless, unclesyd, and Carburize offer significant insight when discussing TOTAL mass of the system. I agree with EdStainless that a 50% reduction may not be possible, but it really depends on the details of gear type, lubrication, temperature, etc. By the way, I meant to say that "the current state of technology really does NOT exist for creating robust titanium alloy gears" in my previous post. Sorry for any confusion.
RE: Alternate Gear Material
RE: Alternate Gear Material