Sunday, April 10, 2011

Re: [MW:10638] help in solving a problem regarding Welding Procedure Qualification

Hi Suresh,
 

As per ASME Sec-IX, QW-253 & QW405.3 (i.e welding progression is a 'Non essential Variable (NEV)') since uphill/down hill progression is NEV, a PQR with uphill can be used for both uphill & downhill and vice versa. But it is a EV (essential variable) for Welder qualification as per QW-353.

 

E7018 is not suitable for vertical down welding, the contractor can revise the WPS with suitable electrode (E7048) (refer SFA 5.1 table-1), with the same PQR qualified with E7018.

 

As per code it is legal to weld 'up to down' and vice versa, but quality point of view, I feel vertical down welding will have some quality issues for tank welding (may be practical problems). But we cannot argue since code permits this!

 

Please check your client spec, permits this deviation (vertical down welding) in tank welding?

 

But in WQT be strict, the welders shall qualify in vertical down welding only.

 

I was read API 650 also, I couldn't able to find any clause to object 'V down' welding?

 

Hope this clarifies,

 

cheers,

 

Raj



On Wed, Apr 6, 2011 at 11:44 AM, Suresh Babu <suresh75.babu@gmail.com> wrote:
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-253Text Box: --,,,,,,,,,,,,,,,,--,,,,,,,---WELDING 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 > 12  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 > 14  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

Text Box: --,,,,,,,,,,,,,,,,--,,,,,,,---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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