Titanium is immune to corrosive attack by salt water or marine atmospheres. It also exhibits exceptional resistance to a broad range of acids, alkalies, natural waters and industrial chemicals. Titanium offers superior resistance to erosion, cavitation or impingement attack.
Titanium is at least twenty times more erosion resistant than the copper-nickel alloys. Titanium and titanium alloys have proven to be technically superior, highly reliable and cost-effective in a wide variety of chemical, industrial, marine and aerospace applications. Titanium is utilized in many critical services due to its unique set of properties. Titanium is 45% lighter than steel and hence contributes to weight saving which is of paramount importance in offshore applications.
Whenever fresh titanium is exposed to the atmosphere or to any environment containing oxygen, it immediately acquires a thin tenacious film of oxide. It is the presence of this surface film that confers on the material its excellent corrosion resistance in a wide range of aggressive services. Titanium requires no corrosion allowance in design.
For sea water applications titanium performs better than copper based alloys. In fact for sea water applications no other material comes close to the economical and technical performance offered by titanium. Titanium is resistant to crevice corrosion up to about 80°C in sea water. Titanium is also immune to microbiologically influenced corrosion.
Typical specifications for Titanium piping
Following is a typical specification for class 150 Titanium Alloy piping 150 psig @ 150° F
Pipes
- 1/2" thru 2"------ Sch 80s ASTM B 861 Gr 2 seamless.
- For large bore pipes use ASTM B862 Grade 2 (welded). Large diameter pipes are fabricated using ASTM B265 Grade 2 plate.
Fittings
- 1/2" thru 2"------ Butt weld fittings to ASTM B 363 Gr WPT2, Wall thickness same as pipe.
Flanges
- 1/2" thru 2" --------- Weld Neck RF flanges to ASTM B 381 Gr F2 material.
- For corrosive applications with lap joint flanges, the stub end face is fabricated to ASTM B363 Grade WPT7
Gaskets
- Spiral wound gasket SS316 with PTFE filler.
Gaskets made from or containing polymers which may release fluoride on thermal or acid decomposition must not be used with titanium piping systems. Note that all titanium alloys are rapidly attacked by hydrofluoric acid even in dilute concentrations and also in fluoride containing solutions below pH7.