The objective of writing this post is seeking your precious help in solving a problem regarding Welding Procedure Qualification
It is required to qualify a Welding Procedure specification for welding the bottom shell plates of an Oil storage tank.
Is it possible to use ESAB ATOM ARC 7018 electrode for Vertical down welding of the shell plates?
As per the AWS 5.1 -2004 Table-1 Electrode Classification, this electrode cannot be used for Vertical down welding and only E7048 can be used for vertical down welding.
According to ASME SEC IX, ( WELDING VARIABLES PROCEDURE SPECIFICATIONS (WPS) Shielded Metal-Arc Welding (SMAW) ) QW-253 the Position QW- 405 is a supplementary essential variable only.
Now the contractor has successfully completed the Welding Procedure Qualification Test using ESAB ATOM ARC 7018 in the vertical down position and submitted for approval.
Kindly advise, is it fair to accept it? Will there be any quality related problems in using this WPS and the ESAB ATOM ARC 7018 for welding Oil storage tanks as per API 650 standards?
The relevant portion of the ASME SEC IX extract, the brochure of ESAB ATOM ARC 7018 and the AWS 5.1-2004 are attached along with this.
Thanking You
Regards
QW-253WELDING VARIABLES PROCEDURE SPECIFICATIONS (WPS) Shielded Metal-Arc Weldi
QW-410
Paragraph Brief of Variables Essential Supplementary Essential Nonessential QW-402 Joints .1 Groove design X .4 − Backing X .10 Root spacing X .11 ± Retainers X QW-403 Base Metals .5 Group Number X .6 T Limits impact X .8 T Qualified X .9 t Pass > 1⁄2 in. (13 mm) X .11 P-No. qualified X QW-404 Filler Metals .4 F-Number X .5 A-Number X .6 Diameter X .7 Diameter > 1⁄4 in. (6 mm) X .12 Classification X .30 t X .33 Classification X QW-405 Positions .1 + Position X .2 Position X .3 ¯ Vertical welding X QW-406 Preheat .1 Decrease > 100°F (55°C) X .2 Preheat maint. X .3 Increase > 100°F (55°C) (IP) X QW-407 PWHT .1 PWHT X .2 PWHT (T & T range) X .4 T Limits X QW-409 Electrical Characteristics .1 > Heat input X .4 Current or polarity X X .8 I & E range X .1 String/weave X .5 Method cleaning X .6 Method back gouge X .9 Multiple to single pass/side X X .25 Manual or automatic X .26 ± Peening X .64 Use of thermal processes X
Technique
Legend:
| + Addition | > Increase/greater than | Uphill | ¬ Forehand | Change |
| − Deletion | < Decrease/less than | ¯ Downhill | ® Backhand |
|
22
QW-253.1
WELDING VARIABLES PROCEDURE SPECIFICATIONS (WPS) Shielded Metal-Arc Welding (SMAW)
Special Process Variables
Paragraph Essential Variables Nonessential Variables for HFO and CRO Hard-Facing Overlay (HFO) (QW-216) Corrosion-Resistant Overlay (CRO) (QW-214) QW-402 Joints .16 < Finished t < Finished t .20 P-Number P-Number .23 T Qualified T Qualified
QW-403
Base
Metals
|
QW-404 Filler Metals |
.12 |
Classification |
|
|
|
.37 |
|
A-Number |
| |
|
.38 |
|
|
Diameter (1st layer) |
QW-405 .4 + Position + Position
Positions
QW-406 .4
Dec. > 100°F (55°C) preheat Dec. > 100°F (55°C) preheat
Preheat > Interpass > Interpass
|
QW-407 PWHT | .6 | PWHT |
|
|
|
.9 |
|
PWHT |
|
| QW-409 Electrical Characteristics | .4 | Current or polarity | Current or polarity |
|
|
.22 |
Inc. > 10% 1st layer |
Inc. > 10% 1st layer |
| |
|
QW-410 Technique | .1 |
|
| String/weave |
|
.5 |
|
|
Method of cleaning | |
|
.26 |
|
|
± Peening | |
|
.38 |
Multiple to single layer |
Multiple to single layer |
|
Legend:
| + Addition | > Increase/greater than | Uphill | ¬ Forehand | Change |
| − Deletion | < Decrease/less than | ¯ Downhill | ® Backhand |
|
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