1) Manufacturing Process
Seamless tubes: Produced by extrusion, piercing, or rotary rolling of solid titanium billets at elevated temperatures, followed by cold drawing or cold rolling. No welding seam is formed during the whole process.
Welded tubes: Produced by cold forming titanium strip or plate into a tubular shape, then longitudinally welding the seam (usually by TIG or plasma welding), and sometimes followed by heat treatment and sizing.
2) Microstructure and Integrity
Seamless tubes: Uniform and continuous structure throughout the wall and circumference, no weld joint, no heat-affected zone (HAZ).
Welded tubes: Have a weld line and a narrow heat-affected zone. Although modern welding ensures high quality, the weld area has a slightly different mrcrostructure from the base metal.
3) Mechanical and Corrosion Properties
Seamless tubes: Excellent and consistent ductility, toughness, creep resistance, and corrosion resistance. Higher resistance to high pressure, fatigue, and stress corrosion.
Welded tubes: Mechanical properties are generally close to seamless tubes in annealed condition, but the weld zone may have slightly lower toughness and fatigue resistance. With proper welding and heat treatment, corrosion resistance can be very close to seamless tubes.
4) Dimensional Range and Cost
Seamless tubes: Suitable for small‑to‑medium diameters and thick walls. Higher material loss and processing cost, so the price is higher.
Welded tubes: More flexible in large diameters and moderate wall thicknesses. Higher material utilization, lower production cost, more competitive price.
5) Typical Applications
Seamless tubes: Preferred for high‑pressure systems, heat exchangers, condensers, aerospace, deep‑sea equipment, reactors, and critical components in seawater desalination.
Welded tubes: Widely used in general industrial piping, non‑critical heat transfer systems, offshore piping, chemical processing, and marine applications where cost efficiency is required.
In summary, seamless tubes provide superior reliability for critical and high‑pressure services, while welded tubes offer economical and reliable solutions for general industrial applications.
