Welding procedure specification for duplex steel

Scope of PQR / WPS for material P-Number 10H

  • Material: ASTM A790 S31803 ASME B36.19M SMLS
  • Pipe size: NPS 2” Sch 80 (5.54 mm)
  • Joint design: Groove, included angle 60 – 70 deg, 6G position.
  • Welding process: GTAW deposit 5.54 mm, manual.
  • Code application: ASME IX

Suggest 3 test coupons for each PQR.

General information

Description of WPS, read more here.

QW-402 Joint details

imageimage

  • QW-402.1 Groove design: see sketchSee ASME B16.25 – groove bevel ends.
  • QW-402.5 Backing: “None”,
  • QW-402.10 Root Spacing: “3.2mm”
  • QW-402.11 Retainers: “None”Retainer are not allowed on product weld of piping process.

QW-403 Base metal

Base metal of the test coupon as mentioned in the PQR, base metal qualification of WPS follow an assigned material in table QW-422 including of P number, group number, thickness qualification.

imageimage

  • QW-403.5 Group no.: “1”, see QW-422,
  • QW-403.6 T limits: “2.77 to 11.08 mm”,
  • QW-403.8 T Qualified: “1.5 to 11.08 mm”, see Table QW-451.1,
  • QW-403.9 t pass > 13 mm: “None“,
  • QW-403.11 P Qualified: “10H”, see table QW-422,

QW-404 Filler metal

  • QW-404.3 Size:“2.4 mm”, refer to ASME II Part C SFA 5.9
  • QW-404.4 F Number: “6”, see table QW-432.
  • QW-404.5 A Number: “8”; see table QW-442,
  • QW-404.12 Spec. or Class. A/SFA.: “A/SFA 5.9 ER2209”,Note: ER2209 for duplex steels, ER2594 for super duplex steels.
  • QW-404.14 Filler: “Yes”;
  • QW-404.22 Consumable Insert : “None”,
  • QW-404.23 Filler metal product form: “Solid”,
  • QW-404.30 Max. Deposit thickness (t): “11.08 mm”, see to table QW-451.1,
  • QW-404.33 Classification: “-“ ,
  • QW-404.50 Flux: “None”.

Recommendation other filler metals, see annex A – table A.3 of API RP 582 2016 edition.

QW-405 Positions

  • QW-405.1 + Position: “All”,
  • QW-405.2 change position: “Vertical-uphill”,
  • QW-405.3 change vertical welding: “-“,

You should set up the test coupons at 6G position where you will be taken in different welding positions (low and high heat input). Because hardness and impact/corrosion test requirements are normally specified in the project for these material

QW-406 Preheat

Preheat temperature will effect to a quality of weldment such as high hardness value, impact test value at heat affected zone, etc.

  • QW-406.1 Decrease > 55 deg. C: “10 deg.C”,If the WPS application to ASME B31.3.
  • QW-406.2 Preheat maintenance: “-“,Not required for this electrode.
  • QW-406.3 Increase > 55 deg. C: “150 deg. C”,We recommend to refer preheat/interpass temperature in table 5 and subsection 8 of API RP 582; Table 330.1.1 of ASME B31.3; Appendix R of ASME VIII Div. 1.

QW-407 PWHT

  • QW-407.1 change PWHT: “None”
  • QW-407.2 change PWHT (T & T range): “-“
  • QW-407.4 T limits: “-“

QW-408 Gas

  • QW-408.1 Trailing or composition: “Argon”
  • QW-408.2 Single, mixture %: “99.997%”, refer to AWS A5.32,
  • QW-408.3 Flow rate: “10-18 lpm”,
  • QW-408.5 Backing flow: “99.997% Argon, 15-18 lpm”.
  • QW-408.9 Backing or composition: “None”,
  • QW-408.10 Shielding or trailing: “-”,

Note:Level of oxygen should not exceed 0.2% when back purging.Mix gas of 98% Ar and 2% Nitrogen for super duplex steels.

QW-409 Electrical characteristics

  • QW-409.1 Heat input: calculation HI = (V x A x 60)/ TS (travel speel – mm/minute).
  • QW-409.3 Pulsing current: “None”,
  • QW-409.4 Current and Polarity: “DC EN”,
  • QW-409.8 I & E range: “A: 60 – 80”, “V: 10-12”,
  • QW-409.12: Tungsten electrode: “2.4mm, 2%thoriated”,

Note:

  1. Follow project requirements about heat input, max. interpass temperature, hardness value, ferrite content, CVN test absorbed to set welding parameter.
  2. Restrict heat inputs to less than 2 kJ/mm for duplex steels and 1.75 kJ/mm for superduplex.
  3. Heat input calculation and limits of heat input value, refer to subsection 8.3 of Norsok M-601 2016 edition.

QW-410 Technique

  • QW-410.1 String/weave: “string”,
  • QW-410.3 Orifice, nozzle or gas cup size: size no.: “4 – 7”,
  • QW-410.5 Method cleaning: “grinding, wire brushing”,
  • QW-410.6 Method back gouge: “None”,
  • QW-410.7 Oscillation: “None”,
  • QW-410.9 Multi to single pass/ side: “Multi”,
  • QW-410.10 Single to multi electrodes: “Single”,
  • QW-410.11 Closed to out chamber: “None”,
  • QW-410.15 Electrode spacing: “None”,
  • QW-410.25 Manual or automatic: “Manual”,
  • QW-410.26 Peening : “None”,
  • QW-410.64 Use of thermal processes: “None”,

Code & specification requirementsMost offshore projects which make use of duplex and superduplex stainless steels specifyrequirements 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.

ReferenceNorsok M-601 – Welding and inspection of pipingAPI RP 582 – Welding guidelines for the chemical, oil, and gas industries.

Discusion and download template at weldinginspections.net

Nguyen Duy Bien
 

Enjoy learning and researching, reading book. Knowledge welding inspection painting inspection.

Skip to toolbar Log Out