New Coating Allows High-Temp Titanium Forming

Titanium can reduce exhaust system weight by 40%, but successfully forming the metal is slow and costly.

Researchers at the Fraunhofer Institute for Machine Tools and Forming Technology in Chemnitz, Germany, say they have overcome both problems with a one-step hydroforming system that can quickly bend titanium exhaust tubing at temperatures above 800 C.

Titanium is light, strong, extremely malleable and temperature and corrosion resistant. But at room temperature, the metal suffer from severe work hardening that requires after-forming treatment to avoid cracking. Work hardening issues disappear at extremely high forming temperatures. But under those conditions the metal tends to stick to the tooling, thus making mass-production techniques difficult.

Developers at Fraunhofer say their system enables titanium tubing to be quickly formed with special nickel-alloy tooling protected by an undisclosed micro-thin coating that prevents the titanium from sticking.

The researchers say their process could allow titanium to be substituted for heavier stainless steel for exhaust manifolds, pipe, mufflers and catalytic converter canisters.