Duplex, super duplex and titanium piping
Spools and assemblies for seawater cooling, desalination, brine and wet chlorine service.
About duplex and titanium piping
Duplex grades need controlled heat input to keep the right phase balance; titanium needs full inert-gas shielding. Both are welded with GTAW and checked for ferrite content or weld colour as part of inspection.
Typical materials
| Service | Alloys often specified | Why |
|---|---|---|
| Dilute and intermediate sulphuric acid | 904L, Alloy 20 | Copper and high nickel keep the alloy passive where 316L corrodes |
| Seawater and brine | Super duplex 2507, 254 SMO, titanium Gr 2, Cu-Ni 90/10 | High PREN or a stable oxide film resists chloride pitting and crevice attack |
| Chlorides with stress (chloride SCC risk) | Duplex 2205, super duplex | The two-phase structure resists chloride stress-corrosion cracking |
| Wet chlorine and hypochlorite | Titanium Gr 2, 7, 12 | Titanium's oxide film is stable in oxidising chlorides |
| Hydrochloric acid and mixed acids | Hastelloy C276 | High molybdenum and tungsten in a nickel base |
| High-temperature steam | A335 P11, P22, P91 with matching forgings | Chrome-moly steels keep creep strength at temperature |
Send your isometrics for a spool quotation
Isometrics, material class and QAP. We reply with price and schedule.
What a spool order includes
| Stage | What is included |
|---|---|
| Isometric review | Spool breaks, field welds and material take-off checked against your isometrics |
| Materials | Pipe from stock or mills; flanges, fittings and bolting from Teshi Group manufacturing |
| Fabrication | Cutting, bevelling, fit-up and welding to qualified ASME IX procedures |
| Testing | Visual, dimensional and the NDT and hydrotest your QAP specifies |
| Finishing | Pickling and passivation for stainless; painting for carbon steel; end caps and tags |
| Documents | Weld map, NDT reports, material certificates and test records per spool |
Welding, testing and traceability
Welding
GTAW root for stainless and exotic alloys with inert-gas purging; procedures and welders qualified to ASME IX.
Testing
- RT or UT per QAP
- Dye penetrant on root and cap
- PMI on alloy components
- Hydrotest where specified
Cleaning
Stainless and nickel alloys pickled and passivated; weld tint removed; ends capped for shipment.
Traceability
Every component's heat number recorded on the weld map, from flanges and fittings we make to pipe from the mill.
Questions buyers ask
How is ferrite controlled in duplex welds?
By qualified procedures with limited heat input and interpass temperature, and by measuring ferrite on welds when the QAP requires it.
Get a quotation from the manufacturer
Send your BOQ, drawing or tender reference. You deal directly with the manufacturer.
- Reply from our estimation team, usually within one working day
- Carbon steel to titanium on one order
- EN 10204 3.1 or 3.2 certificates, third-party inspection welcome
- ISO 9001:2015 certified and IBR approved, since 1971
Drawings and BOQ spreadsheets are easiest by email. Mention your project name.