You have not read far enough into the specification. If you read SFA-5.1 Annex paragraphs A7.6.7.1 and A7.6.5.4, you will find that E7018, E7016, and E7015 are all, all position, low hydrogen, electrodes which may be used with downward progression for diameters 5/32 inch (4.0mm) and less (typically). E7048, addressed in A7.6.10 is specifically compounded to be used in the vertical position with downward progression and therefore may be preferred but is often not readily available. Vertical progression down with E7018 and E7018-1 has been used successfully in welding of tanks and water towers for many, many years. Welding with downward progression takes special expertise and practice in order to handle the flux and obtain sound welds.
John
From: materials-welding@googlegroups.com [mailto:materials-welding@googlegroups.com] On Behalf Of Suresh Babu
Sent: Wednesday, April 06, 2011 3:44 AM
To: materials-welding@googlegroups.com
Subject: [MW:10612] help in solving a problem regarding Welding Procedure Qualification
Dear Gents,
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
Best Regards,
Suresh.
QW-253Error! Filename not specified.WELDING VARIABLES PROCEDURE SPECIFICATIONS (WPS) Shielded Metal-Arc Weldi
QW-410
Error! Filename not specified.
|
Technique
Legend:
+ Addition | > Increase/greater than | Uphill | ¬ Forehand | Change |
− Deletion | < Decrease/less than | ¯ Downhill | ® Backhand | |
22
QW-253.1
Error! Filename not specified.Error! Filename not specified.WELDING VARIABLES PROCEDURE SPECIFICATIONS (WPS) Shielded Metal-Arc Welding (SMAW)
Error! Filename not specified.Special Process Variables
|
QW-403
Base
Error! Filename not specified.Error! Filename not specified.Metals
QW-404 Filler Metals | .12 | Classification | | |
.37 | | A-Number | | |
.38 | | | Diameter (1st layer) |
QW-405 .4 + Position + Position
Error! Filename not specified.Positions
Error! Filename not specified.QW-406 .4
Dec. > 100°F (55°C) preheat Dec. > 100°F (55°C) preheat
Error! Filename not specified.Error! Filename not specified.Error! Filename not specified.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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