Machining and fabricating titanium alloy tubes require specialized techniques and tools due to the material's unique properties: low thermal conductivity, high chemical reactivity at elevated temperatures, and a tendency to work-harden. Standard steelworking practices often lead to poor surface finish, rapid tool wear, and even ignition risk if proper precautions are not taken.
For cutting, abrasive waterjet or precision laser/plasma cutting are preferred for their cold-working nature, which avoids generating the heat that can alter the material's microstructure at the cut edge. For machining operations like turning, boring, or threading, use sharp, carbide-tipped tools with positive rake angles and a rigid setup to minimize deflection. Employ high-pressure coolant directed at the cutting interface to remove heat and prevent chip welding. Speeds should be moderate with low feed rates to control heat generation.
For bending, titanium's springback is significant. Cold bending with a mandrel is standard, but precise over-bending is required to achieve the final desired angle. For tight-radius bends or heavy-wall tubes, induction or furnace heating within a specific temperature range (for the given alloy) may be necessary to reduce bending forces and prevent cracking. Welding titanium tubing demands an inert argon or helium shielding gas envelope covering both the inside and outside of the weld zone to prevent atmospheric contamination (oxygen, nitrogen) which embrittles the weld. Always follow established procedures (e.g., AWS D1.9) and consider post-weld heat treatment for critical applications to relieve stresses.
