1. Why Titanium Piping Can Fail Early
Titanium itself is highly corrosion resistant, so most premature failures in titanium piping come from outside the material: galvanic coupling with less noble metals, crevices that are not designed out, mechanical damage, vibration fatigue and welding contamination. Understanding these mechanisms is the first step to a long life. A well-designed and correctly fabricated titanium line can operate for decades with little maintenance.
2. Design Rules That Protect the Piping
Design the line with flow velocities within the recommended range to avoid erosion, and provide drains at low points so that stagnant corrosive media do not accumulate. Avoid crevices at flange joints, supports and dead legs wherever possible, because crevice corrosion is the main risk in chloride service. Support the pipe at the correct spacing to prevent vibration and sagging, and allow for thermal expansion with properly placed expansion loops or bellows.
3. Managing Galvanic Corrosion
Titanium is cathodic to most common structural metals, so when titanium piping is coupled to carbon steel or aluminium in a conductive electrolyte, the other metal corrodes preferentially. Insulate the flange faces and bolting, use non-metallic gaskets, and avoid direct metal-to-metal contact at supports. In seawater systems, carbon steel connected to titanium should be protected by coating or cathodic protection, and the designer must account for the increased current demand.
4. Welding and Fabrication Quality
Welding is the most demanding step in titanium fabrication. The weld zone must be shielded with inert gas on both the face and the root until it cools, and the work area must be clean and free of moisture, oil and dust. Welds are examined visually for colour, and by penetrant and radiography or ultrasonic testing for critical service. A contaminated weld is brittle and can crack in service, so the shielding practice is never compromised.
5. Cleaning, Maintenance and Operation
Keep the system clean during operation: remove scale and deposits on a planned schedule, and flush lines after shutdown. Avoid cleaning agents that are aggressive to the connected materials, and never use hydrofluoric acid-based pickling solutions without a qualified procedure. Monitor the water chemistry and temperature in heat-transfer service, and keep the operating envelope within the design limits. Correct operation is as important as correct design.
6. Inspection Programme
Run a planned inspection programme with wall-thickness ultrasonic measurements at representative locations, visual checks of welds and supports, and leak testing of flanged joints. Eddy current examination is effective for detecting localised damage in tube and small-bore lines. The inspection data is compared with the previous readings to identify corrosion or erosion trends early. Early detection allows the repair or replacement of a single section instead of a whole line.
Design out crevices and support the line against vibration.
Insulate titanium from connected steel to prevent galvanic attack.
Weld with full inert gas shielding and inspect on a planned schedule.
Frequently Asked Questions
Q: Does titanium piping corrode in seawater?
Titanium itself is virtually immune to seawater corrosion, but connected metals must be protected from galvanic attack.
Q: What is the main cause of titanium piping failure?
Most failures come from design and fabrication issues such as crevices, galvanic coupling, vibration and weld contamination rather than from the material itself.
Q: How do you prevent galvanic corrosion with steel flanges?
Insulate the flange faces and bolting with non-metallic materials and keep the steel surfaces coated or cathodically protected.
Q: Why must titanium welds be shielded so carefully?
Hot titanium absorbs oxygen and nitrogen from the air, which embrittles the weld, so inert gas shielding is applied until the weld cools.
Q: How often should titanium piping be inspected?
The interval depends on the service, but wall-thickness ultrasonic checks and visual weld inspections are typically carried out on a planned schedule.
