WELDING PROCEDURES SPECIFICATIONS (WPS) Neptune Energy
Detailed welding procedure shall be established and qualified in accordance with NoBo as per PED, NEN-EN 13480 and as further required in this Specification
No production welding shall commence until the appropriate procedure tests have been completed and approved.
Repair welding procedures are to be established and, where necessary, qualified.
WELDING PROCEDURE SPECIFICATIONS WPS:
A written welding procedure specification together with test certificates indicating mechanical
properties and chemical analyses of both base materials and welding consumables shall be
submitted to the Company representative for preliminary approval.
No procedure qualification tests shall be performed until the procedure specification has been
granted preliminary approval by the Company representative.
Welding procedure specifications shall contain the following “applicable parameters” with all
explanatory details necessary (see also: ISO 15609):
Material specification of base metals.
Wall thickness and diameter range used for procedure qualification (chemical analyses and
mechanical properties of the base material and welding consumables used for the procedure
tests shall be included in the welding procedure qualification record).
Geometry of welding groove showing allowable tolerances.
Root gap showing allowable tolerances.
Welding position and direction.
Filler metal classification.
Specification of flux.
Gas shielding – flow, mixture, composition (to include back purging).
Number and sequence of the important passes (indicate stringer or weave beads).
Welding current range, voltage range and polarity.
Travel speed or electrode runout length for each pass and range.
Heat input range.
Preheat and interpass temperatures.
Method of cleaning, cutting and machining if applicable.
When any changes in these parameters are made, the welding procedure qualification shall be
set up as a new WPS, and shall be completely re-qualified.
WELDING PROCEDURE QUALIFICATION WPQ:
A qualified welding procedure specification is one which is tested to and has achieved the
requirements of this Specification, and has been witnessed and approved by the Company’s
representative and the Certifying Authority.
The Contractor shall conduct the tests required to qualify each procedure and tests shall be
witnessed by the Company representative and the Certifying Authority. The results of previous
welding procedure qualification tests may be accepted by the Company’s representative and
the Certifying Authority providing:
a) Welding specifications and resulting test certificates are authenticated by the original
documentation, or by certified copies.
b) The Contractor submits documentation, for the approval of the Company representative, to
demonstrate that all the appropriate test requirements, applicable parameters, welding
conditions, equipment and materials as used in the original welding procedure qualification
tests, comply with and fulfil all the appropriate test requirements of this Specification.
All services in connection with the establishment of welding procedures, welders performance
qualifications, related tests and additional corrosion tests shall be by the Contractor.
Qualification of a welding procedure is restricted to the Contractor or Subcontractor where
the test weld was produced.
Welding procedure and welders performance qualification shall be new and subject to
approval by Company’s representative.
Welding procedure qualification tests shall be conducted to verify the WPS’s, and shall
simulate, as far as practical the conditions and materials to be used for production welding.
A qualified procedure is valid only for diameters and thickness in accordance with PED and
PROCEDURE QUALIFICATION RECORD PQR:
The specific parameters of the WPS and test results of the WPQ shall be recorded in the
procedure qualification record PQR, signed by the responsible welding engineer, QA engineer
INSPECTION OF PROCEDURE QUALIFICATION TEST WELDS:
The base material, welding consumables and welding process shall be equal to those as
specified in the welding procedure specification WPS.
Dimensions of the weld samples shall be sufficient to provide for the required test pieces as
defined in the PED and NEN-EN 13480.
During welding, the welder’s name and all data listed in the WPS shall be recorded.
All weld samples for the procedure qualification shall be subject to NDT (radiographic,
ultrasonic testing and surface examination) and acceptance in accordance with this
Specification prior to mechanical testing. The acceptance criteria for mechanical testing shall
be in accordance with PED and NEN-EN 13480.
A cross-section of the weld shall be made for microscopic and a macroscopic investigation.
The cross-section shall clearly show the weld metal, fusion line and heat affected zone. The
ferrite content shall be measured using a magna-gage equipment or an alternative tool
approved by the Company. At least 5 measurements shall be made. The ferrite content shall
be expressed in a extended ferrite number EFN and the average value shall be between 30
and 65 for the weld metal and heat affected zone. Any single value shall not exceed a 10% of
Hardness tests shall be carried out at one line 2 mm away from both surfaces of weld cross-
section and halfway between these surfaces. Zones of indentations should give three values in
the base material BM on both sides of the weld in addition to those in the weld metal WM and heat affected zone HAZ.
The minimum distance between the indentations should be two and half times the width of
the previous indentation. The maximum allowable hardness measured is 305 HV 10 (305
Vickers hardness measured on 10 kg load). Maximum allowable hardness variation between
any point indicated may be 100 HV 10.
Charpy-V notch impact test shall be carried out when the wall thickness of pipe or fitting
exceeds 5 mm.
Three notch impact test pieces (standard specimen 10 x 10 mm) shall be taken in transverse
direction on the weld and shall be tested at Vt-test temperature in accordance with EN 13480
requirements for an Vc-assessment temperature of minus 20 degrees centigrade. The average
impact value shall not be less than 52 Joule with only one value lower, but not below 39 Joule.
The dimensions, preparation and testing of the impact test specimens shall be in accordance
with NEN-EN 875.
Subsized specimen may be used when standard specimen cannot be prepared. In this case
the required values may be lowered accordingly.
Pitting corrosion test to ASTM G48 ( method A ) test method at 22 degrees centigrade.
Exposure time 24 hours ( no pitting at 20x magnification and weight loss less than 5.0 g/m²).
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