Titanium

Titanium Diffusion Hardening (TDH)

Alleviate wear scarring with highly efficient, high load, lightweight bearings

Titanium Diffusion Hardening (TDH) is a surface-hardening process for titanium alloys that significantly improves its tribological properties in lined self-lubricating bearing systems by providing a high-hardness outer surface to the titanium base material. This is a diffusion hardening process (not a coating); conducted in a controlled atmosphere that yields a deep, uniform, hardened case layer within the titanium component. TDH will consistently yield a high-hardness case layer with an affected depth that is unmatched by other titanium surface engineering processes.

“Using our proprietary Titanium Diffusion-Hardening process, we’ve really been able to raise the bar for lightweight self-lubricating plain bearing systems. Using a diffusion-hardened Ti64 mating surface, we’ve been able to achieve KAron wear and friction results equivalent to those we experience with high-hardness stainless steels (at nearly half the assembly weight)” said Mat Mormino, VP of Engineering, KAMAN Specialty Bearings & Engineered Products.

In applications that require low overall weight, titanium alloy is a popular choice for bearing material. For years customers using these bearings struggled with the fact that at very high bearing loads (such as those specified in AS81820), titanium alloys tend to exhibit less-stable dynamic friction coefficients. Titanium alloy bearings can also be subject to surface distress (wear scarring of the titanium). Using a diffusion-hardened Ti64 mating surface within self-lubricating bearing systems, KAMAN Specialty Bearings & Engineered Products has been able to alleviate wear scarring, providing customers with a solution for highly efficient, high load, lightweight bearings.

TDH treated titanium Journal bearings have successfully passed the test requirements of AS81934 (High Load-Wear) at four times the required cycles with only one-tenth the allowable wear. From the figure below one can easily discern that during high load-wear testing, bearings utilizing the TDH capability significantly outperform those that have not been treated. In addition to the AS81934 test, TDH treated titanium spherical bearings have also passed the respective tests of AS81820 (high-load spherical bearing tests).