Combining 2 PQRs

[lalitmalla]

Dear Expert,

I am having 2 PQRs i.e.:
1. 2" Sch. 80 Pipe (thk.-5.54mm) - GTAW (70S-2)
2. 6" Sch. 160 Pipe (thk.-18.26mm) - SMAW (7018)

My question is: Can I combine these 2 PQRs for buiding up one more WPS for 8" Sch. 80 Pipe (thk.-12.70mm)using GTAW+SMAW (Root and hot with GTAW and filling and capping with SMAW)

Thanx in advance for your valued comments...

 

[david339933]

No, you cannot. Your GTAW PQR must be done on a coupon at least 1/2" thick. See QW-200.4(b)

 

[fleischfresser]

The diameter is not a variable for a PQR
“QW-211 BASE METAL
The base metals may consist of either plate, pipe, or other product forms. Qualification in plate also qualifies for pipe welding and vice versa. … “

That mean we have to consider only the thickness ranges.

PQR1: 5.54 mm, GTAW: qualifies for
base metal thickness T 1.5 – 11.08 mm(without impact test requirements), 2.77 – 11.08 mm (with impact test requirements)
deposited thickness t max. 11.08 mm

PQR2: 18.26 mm SMAW: qualifies for
base metal thickness T 5 – 36.52 mm (without impact test requirements, 16 – 36.52 mm(with impact test requirements
deposited thickness t max. 36.52 mm

If you combine both PQR the qualified thickness ranges still remain. That means for the base metal thickness you can use only the overlap of both base metal thickness ranges.
Combination of both PQR’s leads to the following:
Thickness ranges without impact test requirements: 5 – 11.08 mm, deposited weld metal GTAW max. 11.08, SMAW max 36.52 mm
Thickness ranges with impact test requirements: Combination of both PQR’s is not possible, because there is no overlap for the base metal thickness range.

Therefore the combination of the above PQR's do not support the welding of a joint 12.70mm thick.


Regards - Juergen

 

[david339933]

The above works for combining different WPSs in the same joint, but I am yet to be convinced that two different PQRs can be used in the same WPS outside of QW-200.4(b).

Interpretation: 1-46-O6
Subject: Section IX, QW-200.2(f) and QW-200.4
Date Issued: September 19, 1985
File: BC85-328
Question: Does the combination of 2 PQRs, each of different processes, support a WPS
combining the two processes in a single joint, with all essential and supplementary essential variables unchanged?
Reply: No.

I currently have a request for interpretation, to see if this is still applicable.
Request Record: 16-3074

 

[david339933]

Finally received a response:

Item: 16-3074
Dear Sir,
Our understanding of the question in you inquiry and our reply is as follows:

Question: May a combination of two PQRs each of different welding processes, support a WPS combining the two processes in a single joint with all the essential and supplementary essential variables unchanged?
Reply: Yes, provided the base metal and deposited weld metal thickness limits of QW-451 are satisfied for each process.

 

[DekDee]

David,
This one makes me scratch my head ?

Interpretation: IX-15-05
Subject: QW-451.1
Date Issued: September 11, 2014
File: 14-786
Background: One PQR was qualified with GTAW on a test plate thickness of 3/8 in. (0.375 in.). A second PQR was qualified
with SMAW on a test plate thickness of 3/4 in. (0.75 in.).

Question: Can a WPS supported by both PQRs be qualified for 1/16 in. (0.0625 in.) to 3/4 in. (0.75 in.) without the minimum
thickness applicable to the SMAW process being restricted to 3/16 in. (0.1875 in.) per QW-451.1?

Reply: No.

The way I am reading the answer is you cannot write a GTAW/SMAW WPS with a qualified range of 1/16" (1.5 mm) to 3/4" (19 mm) but you can write one for 3/16"(5 mm) to 3/4"(19 mm).
This seems to contradict QW 200.4 (b).
Your thoughts ?
Cheers,
Shane

 

[metengr]

Keep in mind the Interpretation process is unique in the sense the committee typically rewords the original Inquiry to affect a broader audience appeal or to provide clarity. Sometimes this works and other times I wonder if we really understood the question.

Second comment, the committee membership changes over time and suddenly perspectives change. This is why old interpretations should be carefully considered for later editions of the code especially when code revisions and rewrites happen. Just a view provided from a committee member.

 

[david339933]

I don't believe that it contradicts 200.4(b), as that is used to extend the qualified base metal thickness. 1/2" ooupon GTAW coupled with 1-1/2" SAW coupon to give GTAW/SAW WPS qualified for 8". Your interpretation doesn't state that you could write a wps for 3/16" to 3/4" either....the problem with "no" replies.

But 200.4(b) seems to be the only place in the code that states you can combine different process pqrs into one WPS....which is backed by the original interpretation I stated.

IMO this interpretation sets things right. If you can use multiple procedures in a single joint (variables unchanged) then you should be able to write a combo wps for the same.

 

[DekDee]

David,
You have lost me here.
Your 1st post stated the OP couldn't do what he/she proposed.
Does your last post mean in your opinion the OP can or cannot do what they proposed ?

metengr,
Agree 100% with your comments.
I am involved with the B31.3 committee IRG (International Review Group) - which allows me to comment but not vote on ballots.
Has given me a great understanding of what goes on "behind the scenes" in the committee.
Cheers,
Shane

 

[david339933]

OP cannot do what they proposed because it contradicts 200.4(b)....OP is trying to extend GTAW base metal qualified to cover 12.7mm - when in is only qualified for 11.08mm (2 x 5.54). If the GTAW was done on 1/2" then the WPS could be written to cover up to 36.52mm ( 2 x 18.26), using GTAW for root.

What I am saying is that the code doesn't specifically state you can combine 2 different pqrs of different processes into one WPS.....other than 200.4(b) as above.

Example: 3/8" coupon GTAW - 1/16" to 3/4" qualified
3/8" coupon SMAW - 1/16" to 3/4" qualified
Code doesn't state I can combine these two pqrs into one wps.....GTAW/SMAW 1/16" - 3/4". The first interpretation I posted states that NO you cannot combine these two pqrs into a single wps, but the new interpretation states you can.

 

[DekDee]

David,
What do you think about this one ?
Not sure what the relevance of the tube wall thickness being less than 1 in. is ?

Interpretation: IX-92-75
Subject: Section IX, QW-200.4@), Combination of Welding Procedures
Date Issued: September 22, 1993
File: BC93-490

Question: When writing multi-process welding procedures per QW-200.4(a), where the tube wall thickness is less than 1 in., using a separate qualification for the root deposit only, must the root deposit qualification coupon be 1/2 in. minimum thickness as stated in QW-200.4(b)?

Reply: No.

 

[david339933]

200.4(a) talks about using more than one wps in a single joint. It also talks about multi-process wpss being used individually or in different combinations, but doesn't address different process pqrs being used to write a multi-process wps.

If wall thickness is less than 1", say 1/2", then a gtaw wps qualified on 1/4" coupon would be qualified for 1/2" basemetal and therefore the 1/2" min requirement of 200.4(b) wouldn't be necessary.

You could use gtaw wps + another process wps qualifed for at least 1/2" thick basemetal in the same joint. There is no need to extend the base metal qualified by the process that deposited the root layer, as it is already qualified to that thickness.

If you wanted to weld anything thicker than 1", say 8" thick, then the code gives a way of not having to weld an 1-1/2" GTAW coupon to achieve this....as long as the pqr coupon was 1/2" thick you can combine pqrs to achieve the 8" max base metal qualified.

This interpretation seems to infer that a combo wps can be done, contradicting the 1985 interpretation, but in line with the most recent I had posted.

 

[CWEng]

From the interpretation below, I think the subject has been revisited since 1985, and the answer was different:

Standard Designation: BPV Section IX
Edition/Addenda: 2015
Para./Fig./Table No: QW-200.4, QW-200.2(f)
Subject Description: SC IX; QW-200.4, QW-200.2(f) - Combination WPS
Date Issued: 06/06/2017
Record Number: 16-3074
Interpretation Number : BPV IX-17-30
Question(s) and Reply(ies): Question: May a combination of two PQRs each of different welding processes, support a WPS combining the two processes in a single joint with all the essential and supplementary essential variables unchanged?

Reply: Yes, provided the base metal and deposited weld metal thickness limits of QW-451 are satisfied for each process.

 

[david339933]

That is the interpretation I received...as posted above.