Beta titanium alloys (Ti-15-3-3-3, Ti-3-8-6-4-4, Beta-C) are the strongest, toughest members of the titanium family — and the most brutal to drill. Low thermal conductivity, aggressive work hardening and edge-grabbing combine to punish anything short of a disciplined low-speed process.
Alpha and alpha-beta titanium alloys (Ti-6Al-4V) are already hard to machine. Beta alloys go further: they are denser in beta-phase content, stronger, lower in thermal conductivity, and far more springy. The cutting edge sees concentrated heat, the chip grabs and welds, and the work-hardened surface destroys the next pass. Deep holes in beta titanium demand the most conservative parameters in the titanium family.
| Parameter | Beta titanium (Ti-15-3, Beta-C) |
|---|---|
| Gundrill Vc (m/min) | 8–20 |
| BTA Vc (m/min) | 8–15 |
| Feed @ Ø10 mm (mm/rev) | 0.010–0.025 |
| Coolant | Oil, high EP |
| Coolant pressure | 100–200 bar (gundrill) |