In Situ Lubrication in Forging of Pure Titanium Using Carbon Supersaturated Die Materials

Area of Science:

• Materials Science
• Tribology
• Manufacturing Engineering

Background:

• Dry forging of pure titanium presents challenges due to high adhesion and work hardening.
• Existing lubrication methods are often insufficient for high-reduction processes.

Purpose of the Study:

• To develop a new in situ solid lubrication method for dry forging of pure titanium.
• To investigate the formation and effectiveness of a free-carbon tribofilm.

Main Methods:

• Development of carbon supersaturation processes for ceramic and metal dies.
• In situ formation of a free-carbon tribofilm at contact interfaces.
• Upsetting tests of pure titanium bars with high reduction in thickness (up to 70%).
• Analysis using SEM-EDX, EBSD, and Raman spectroscopy.

Main Results:

• A free-carbon tribofilm was successfully formed in situ, protecting die surfaces.
• Achieved a low friction coefficient (0.05–0.1) during upsetting.
• Significantly suppressed work hardening in pure titanium.
• Demonstrated effective lubrication for high-reduction dry forging.

Conclusions:

• The in situ solid lubrication method using a free-carbon tribofilm is effective for pure titanium dry forging.
• The mechanism involves carbon diffusion and agglomeration to form a protective film.
• This approach offers a viable solution for reducing friction and work hardening in demanding forging operations.