Welding procedure specification - GTAW (ASME IX P-Number 10H)

Preset welding procedure for P-No. 10H.

Code & specification requirements
Most offshore projects which make use of duplex and superduplex stainless steels specify
requirements for a similar range of properties:

  • Strength.
  • Hardness.
  • Toughness (Charpy test).
  • Ferrite and microstructure.
  • Corrosion (ASTM G48A test).
  • Other common weld procedure requirements, eg NDT, bend tests.

Note: Impact testing is required for nominal wall thickness ≥ 6 mm.

Reference
Norsok M-601 - Welding and inspection of piping
API RP 582 - Welding guidelines for the chemical, oil, and gas industries.

Download template: WPS , WPS register list .

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Other notes when GTAW weld for duplex stainless steel

duplex%20presentation_Page_63

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Advantages

  • Non-consumable electrodes
  • No flux is required because inert gas shields molten metal.
  • No slag inclusion problems, no spatters.
  • High quality
  • Achived good profiles
  • Suitable for welding of thin members.
  • Wide range of metal using and welding consumables likes aluminium, copper or dissimmilar.
  • It can be done in both automatic and manual.

Disadvantages

  • Gives low deposit rates compared with other welding process.
  • Required high skills of welder.
  • High initial cost.
  • Less economical than MMA, GMAW, SAW for thicker metal 10 mm and above.
  • Tungsten inclusions may occur.
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Why T limits qualified from 2.77 to 10.08 mm, instead of 1.5 to 11.08 are detailed in QW-451.1?

Thanks

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Yes, that is T limits when CVN requirement.
If not, range of WPS qualification is 1.5 to 11.08 mm.

  • QW-403.8 T Qualified: “1.5 to 11.08 mm”, see Table QW-451.1,
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