General guide lines for procedure and
performance qualification
Referenced by all ASME code of
construction
Covers welding as well as Brazing
WPS:
It is a written procedure prepared to provide welding
parameters for making welds as per code requirement.
Can be used on production only after successful
qualification of supporting PQR(s).
A WPS can be supported by one or multiple PQR(s).
PQR:
Record of the actual welding data used to weld a test
coupon.
Also contains test results (Mechanical, Chemical & Non
Destructive Test) of the test coupon.
Code of
construction
Detailed
drawing of
weldment
Material
Thickness
Configuration
Process
Contract/Customer/
Code/TPI
Preheat/Postheat/
PWHT
requirements
Skilled welder
Good welding m/c
with accessories
Application
•
Variables are defined for each process in QW-250
through QW-280
•Each variable shall be addressed with facts, e.g.
yes, no, none or any other meaningful definition
• A PQR is a record of welding data used to weld a test coupon • It is a record of actual variables recorded during the welding
of the test coupons
• PQR shall document all essential and, when required, all supplementary essential variables for each welding process
• Nonessential variables may be recorded (optional)
• All variables are actual values used during welding of the test coupon
• Changes to a PQR are not permitted as it is a record of what happened during a particular welding test, except for
editorial corrections and addenda
• All changes except editorial and those invoked by an
Addenda, require re-qualification and recertification of the PQR
Preheat
PWHT
Joint design
Backing material
P Number
Welding Process
Filler metal
Electrode
Method of back
gauging
Essential
Non-essential
Supplement
al essential
Essential variable:
A change in welding condition which will affect the mechanical properties other than toughness of weldment
Any change in this variable calls for re-qualification of PQR
Supplementary – essential variable:
•A Change in welding condition which will affect impact toughness of weldment
•Change in this variable calls for re-qualification of PQR in case there is requirement of impact toughness for the vessel
Non - essential variable:
•No change in mechanical properties is expected
A WPS shall record all essential, supplementary
essential & non essential variables
QW 402: Joints
•
Non essential variables
-Groove design,
Backing,
Root gap,
Retainers
QW 403:
Essential variables
- P No,
Thickness of base material qualified,
Thickness of each pass beyond 13 mm for
multipass welding
•
Supplementary essential variables
- Group no for base material
Base Metal P Numbers
P1 - P11 Steel P21 - P25 Al alloys P31 - P35 Cu alloys P41 - P47 Ni alloys P51 - P53 Ti alloys P61 - P62 Zr alloysBase Metal P Numbers
Examples of P nos P1 C Steel P3 1/2 Mo steels P4 1 Cr 1/2 Mo steels P5A 2 1/4 Cr 1 Mo steels P6 13 Cr steel P7 17 Cr steel P8 ASS P9A 2 1/2 Ni steels P10A Mn - 1/2 Ni - V steels P11 9 Ni steels
Base Metal for WPS
Test Coupon Base Metal qualified
Px - Px Px
Px - Py Px to Py
P3 - P3 P3 - P3, P3 - P1
P4 - P4 P4 - P4, P4 - P3, P4 - P1 P5A - P5A P5A - P5A, P4 - P4, P4 - P3,
P4 - P1
P4 - P3, P4 - P1 P4 - P3, P4 - P1 P5A - P4, P5A - P3} P5A - P4, P5A - P3
Impact Specimens
Fillet Weld Fracture
Tensile Specimens CTOD Specimens
Bend Tests Non Destructive Exam
QW 404:
Essential variables -
•F no, •A no,
•Thickness of deposited weld metal •Flux / wire class,
•Alloy addition through flux (SAW), •Re-crushed slag (SAW)
Supplementary essential variables
-
•Electrode Diameter > 6 mm for SMAW
Non essential Variables
–
F-Number grouping of electrodes &
welding rods is based essentially on their
usability characteristics to reduce the
number of tests required to qualify
procedures and welders.
A - NUMBERS
Used to describe the weld deposit chemistry
and is applicable only to the ferrous metals
for the qualification of a welding procedure.
F
Number
Description
1 Heavy Rutile Coated Iron Powder Electrode
2 Most Rutile Coated Iron Powder Electrode
3 Cellulosic Electrodes 4 Basic Coated Electrodes
5 High Alloy austenitic stainless steel & Duplex Stainless steel Electrodes
6 Any Steel or coated Wire (with flux or Metal)
2X Aluminum & Its Alloys Electrodes 3X Copper & Its Alloys Electrodes 4X Nickel & Its Alloys Electrodes 5X Titanium & Its Alloys Electrodes 6X Zirconium & Its Alloys Electrodes 7X Hardfacing Overlay Electrodes
F Number ASME
Specification
AWS
Classification
4 SFA 5.1 E7018, E7018-1
6 SFA 5.18, 5.28, 5.29, 5.30 All classification 43 SFA 5.11 ENiCrFe-2, ENiCrFe-3 43 SFA 5.14 ERNiCr-3
71 SFA 5.13 ECoCr-A, ECoCr-B ECoCr-C, ECoCr-E
A-No .
Types of Weld Deposit
Weld Metal Analysis, % [Single values shown are maximum ]
C Cr Mo Ni Mn Si 1 Mild Steel 0.20 … … … 1.60 1.00 2 Carbon-Molybdenum 0.15 0.50 0.40-0.65 … 1.60 1.00 3 Chrome (0.4% to 2%)-Molybdenum 0.15 0.40-2.00 0.40-0.65 … 1.60 1.00 4 Chrome (2% to 6%)-Molybdenum 0.15 2.00-6.00 0.40-1.50 … 1.60 2.00 5 Chrome (6% to 10.5%)-Molybdenum 0.15 6.00-10.50 0.40-1.50 … 1.20 2.00 6 Chrome-Martensitic 0.15 11.00-15.00 0.70 … 2.00 1.00 7 Chrome-Ferritic 0.15 11.00-30.00 1.00 … 1.00 3.00 8 Chromium-Nickel 0.15 14.50-30.00 4.00 15.007.50- 2.50 1.00 9 Chromium-Nickel 0.30 19.00-30.00 6.00 15.00-37.00 2.50 1.00 10 Nickel to 4% 0.15 … 0.55 0.80-4.00 1.70 1.00 11 Manganese-Molybdenum 0.17 … 0.25-0.75 0.85 1.25-2.25 1.00 12 Nickel-Chrome-Molybdenum 0.15 1.50 0.25-0.80 1.25-2.80 0.75-2.25 1.00
QW 405:
Supplementary essential variables
-
•Change from any position to vertical uphill progression for SMAW.
Non essential variables
–
QW 406:
Essential variables
-
•Decrease of more than 55ºC in the preheat temperature qualified.
Supplementary essential variables
-
•Increase of more than 55ºC in the interpass temperature qualified.
Non essential variables
–
•Change of preheat maintenance i.e. Dehydrogenation Treatment (DHT) etc.
QW 407:
Essential variables -
•Any change in the following conditions:
No PWHT,
PWHT below lower transformation temperature, PWHT above upper transformation temperature,
PWHT between upper & lower transformation temperature.
Supplementary essential variables –
•Increase in job PWHT soaking time beyond 20% of
the soaking time qualified in PQR.
QW 408
:•Essential variables
-Single shielding gas to mixture of gasses, Different types of mixed gasses,
Percentage composition of gasses for GMAW, FCAW,
GTAW process
•Non essential variables
–Flow rate,
Backing gas flow rate Backing gas composition
QW 409:
•Supplementary essential variables -
Increase in heat input ,
Change in current type ( AC / DC), Change in Polarity (DCEN / DCEP)
•Non essential variables –
Change in current range,
QW 410:
Supplementary essential variables
-
•Change in multiple to single pass per side . •Change of Single to multi electrode for SAW
Non essential variables
–
•Change of Stringer bead to Weave bead technique or vice versa,
•Method of cleaning,
Purpose
•To validate the capability of an welder to deposit sound
weld metal following a qualified welding Procedure
•Establish the range of qualification to minimize the
number of qualification
•Guide line for renewal of qualification
Welder
•Person performing welding by manipulating arc by hand
Welding Operator
•Person performing welding by controlling the manipulation of
A change in welding condition which will affect
the ability of welder to deposit sound weld metal
Any change in this variable calls for
re-qualification
Essential Variables
Change in welding Process
Change from direct to remote visual control
Deletion of Auto joint tracking
Addition of welding position not qualified
Deletion of consumable inserts
Deletion of backing
OD of Test coupon,mm Minimum OD Qualified, mm Less than 25 mm Size welded
25 to 73,mm Over 73 mm
25 mm 73 mm
Welding Performance Qualification
Test coupon More than 2 welders different procedure can do a single test
coupon. Failure then both are failed.
Retest - 2 consecutive test coupons to pass
Renewal if no welding for 6 months. Single test coupon plate/pipe, any thickness,
material, position. If passed then complete previous qualification is restored.
Welding Performance Qualification
1. Variables for SMAW
2. Removal of backing
3. Change in Pipe diameter 4. Change in P number
5. Change in F Number
6. Change in thickness of weld deposit 7. Change in welding position
Variables for GTAW
1. Removal of backing
2. Change in Pipe diameter
3. Addition / deletion of filler metal 4. Addition / deletion of insert
5. Change in P number 6. Change in F Number
7. Change in solid filler to flux cored filler metal 8. Change in thickness of weld deposit
9. Change in welding position 10. Removal of inert gas backing 11. Change in current or polarity
Radiography
No crack or LOP or LOF
Any elongated slag >1/8” for t <3/8”
1/3 t for t = 3/8 - 2 1/4” 3/4 “ for t > 2 1/4”
Any group of slag in a line with aggregate length t in
12 t unless separated by 6L
Max permissible dimension for rounded indication
smaller of 20% of t or 1/8”
For thickness<1/8”, max no of accepted rounded
indication
12 in 6” length
For thickness>1/8”,
PLATE QUALIFICATION
Visual examination Radiography
2 no of Tensile test
2 no each of Bend test - face and root bend ( 3t for both C steel and alloy steel 180 deg bend) 1 no Micro examination 1 no Macro examination PIPE QUALIFICATION Visual examination Macro examination
2 no each of Bend test - face and root bend ( 3t for C steel and 4t for alloy steel 90 deg bend)
PLATE QUALIFICATION Radiography
1 no each of Bend test - face and root bend
PIPE QUALIFICATION
1 no each of bend test - face and root bend Macro examination