Titanium coils can be considered its "golden partner" in industrial applications—both are renowned for their corrosion resistance, but titanium offers excellent overall performance at a much more affordable price, thus broadening its application range.
If your operating medium is a complex mixture of strong acids and you have extremely high requirements for equipment lifespan, titanium coils may be your "one-and-done" solution. For most chemical, marine, and pharmaceutical engineering projects, titanium coils provide sufficiently excellent corrosion resistance while significantly reducing equipment investment costs. Furthermore, titanium itself offers several grades to choose from: TA1/TA2 for general corrosive environments; and TA9 (titanium palladium) or TA10 (titanium molybdenum nickel) alloys for more demanding environments such as strong acids and crevice corrosion.
Titanium has limited resistance to some reducing acids (such as hydrochloric acid and dilute sulfuric acid) at room temperature. If your operating conditions involve such media at high concentrations, you need to confirm the suitability of the material or consider upgrading to a titanium alloy. The manufacturing of specialized titanium coils places high demands on welding processes (requiring inert gas protection) and bending techniques to prevent oxidation and cracking. Choosing an experienced professional manufacturer is crucial. Corrosion resistance varies (titanium is resistant to seawater but not to concentrated hydrochloric acid; tantalum is resistant to concentrated hydrochloric acid but not to HF), with tantalum exhibiting stronger chemical inertness but costing 2-5 times more.
Titanium exhibits almost no corrosion in seawater, chlorides, and wet chlorine gas; however, it is not resistant to concentrated hydrochloric acid, concentrated sulfuric acid, and hydrofluoric acid above room temperature. The surface TiO₂ oxide film is the core of its corrosion resistance, and it can self-repair when damaged. Its physical density is 4.51 g/cm³ (approximately 60% of steel), and its melting point is 1668°C; it maintains high toughness even at low temperatures (-253°C); its thermal conductivity is lower than copper/aluminum but better than 316 stainless steel. Pure titanium has moderate strength in the annealed state and can be strengthened by cold working; welding requires high-purity argon gas protection to prevent embrittlement.
Pipe preparation involves extrusion + multi-pass cold drawing + vacuum/inert atmosphere bright annealing; seamless titanium tubes are preferred for thin-walled coils; welded tubes are limited to low pressure applications and require TIG/EB welding + post-weld pickling to remove the oxide layer. Anti-wrinkle filled thin-walled tubes are often filled with inert powder/fine sand and sealed to prevent wall collapse and excessive ellipticity during winding. Forming and heat treatment involve spiral die winding/CNC bending; vacuum annealing after cold forming eliminates residual stress; pickling and passivation improve corrosion resistance. Inspection includes dimensional/wall thickness testing, PT/RT flaw detection, helium leak detection, and corrosion testing (e.g., ASTM G48 chloride stress corrosion testing).
The medium and temperature/pressure must not be used with hot concentrated hydrochloric acid/sulfuric acid/HF; TA9/TA10 is preferred for chloride-containing/crevice corrosion conditions; for pressures > 2.5MPa, wall thickness and bending radius must be calculated. Connection methods should prioritize argon arc welding + flange/socket welding; avoid threaded connections (prone to crevice corrosion); welding must be back-side purged with argon. Cleaning and storage: After passivation, dry and package; do not use hard tools such as wire brushes; use neutral/weakly alkaline solutions for cleaning to avoid damaging the oxide film. Key differences from tantalum coils: titanium coils are resistant to seawater/chlorine-based media, have lower cost, and are lighter.
