PWHT soaking time for impact testing applicable vessel

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Muhammed Ibrahim PK

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Dec 8, 2021, 1:20:51 AM12/8/21
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Gentle men,

A pressure vessel required PWHT, and Impact test. The vessel thickness is 46 mm. The PWHT of this vessel required as per code is 108.6 minute.

The contractor submitted a PQR which is performed 60 minutes (1hr)  and  720 minute (12hrs) PWHT and and all mechanical test done in both holding time.

As ASME sec IX, clause 407.2 

"
QW-407.2 A change in the postweld heat treatment
(see QW-407.1) temperature and time range
The procedure qualification test shall be subjected to
PWHT essentially equivalent to that encountered in the
fabrication of production welds, including at least 80%
of the aggregate times at temperature(s). "

As per the above clause the PQR is acceptable?. It does not meant PQR shall be essentially equivalent within 80% of actual production PWHT?. Since the manufacture done 60 minutes and 720 minutes, and the production PWHT comes in between holding time (108.6) the PQR will be acceptable?

 
Thanks & Regards
Muhammed Ibrahim PK

pgos...@rogers.com

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Dec 8, 2021, 2:40:47 PM12/8/21
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By the law of rationales , you should accept this combination of   PQRs. Why, as explained below:

 

Your calculated time for soaking is -108.6 minute. 80% of that time is:- 108.6x 0.8= 86.88 @ 87 minutes.

  • Vendor submitted PQR No1, is for 60 minutes
  • Vendor submitted PQR No2, is for 720 minutes. 720 minutes of soaking time is well over the requirements of 89 minutes as per the above calculations.

 

In fact, vendor had submitted both the PQR’s to safeguard the 87-minute requirement, as PQR No1 was for 60 minutes and did not meet the cut off requirements of 87 minutes. Hence, they substantiated the Sec IX requirements with the PQR of longer soaking time, i.e., 720 minutes.

 

In fact, the PQR with 720 minutes meet the requirements of 108.6 minutes of PWHT time. If I would the welding engineer or approving inspection engineer, I would have asked the PQR 1-(60 minutes) to be removed from the dossier, so as to avoid the confusion.

Since vendor had submitted both PQRs and if they want to retain both in the documentations,  ask for a clarification note in the above-mentioned justification to close the issue.

Also you’ve to make sure that both PQR1 & PQR2 meet specifically charpy impact & hardness( if applicable)  in addition to the other mechanical test.

 

Hope this clarifies your query.

 

Thanks.

 

 

Pradip Goswami.P.Eng, IWE.

Independent Consulting Welding & Metallurgical Engineering Specialist

Consultant: SNC Lavalin Inc. (Nuclear &Non-Nuclear)

Saudi Aramco Approved Designated Project Welding Engineer (DPWR)

Qatar Petroleum Approved, SME-Materials & Corrosion Engineering.

Linkedin: https://www.linkedin.com/in/pradip-goswami-2999855/

Email:pgos...@rogers.com,pradip....@gmail.com

Cell/Whasapp:1-905-9793232

 

From: material...@googlegroups.com <material...@googlegroups.com> On Behalf Of Muhammed Ibrahim PK
Sent: December 7, 2021 2:28 AM
To: material...@googlegroups.com
Subject: [MW:32639] PWHT soaking time for impact testing applicable vessel

 

Gentle men,

 

A pressure vessel required PWHT, and Impact test. The vessel thickness is 46 mm. The PWHT of this vessel required as per code is 108.6 minute.

 

The contractor submitted a PQR which is performed 60 minutes (1hr)  and  720-minute (12hrs) PWHT and all mechanical test done in both holding time.

 

As ASME sec IX, clause 407.2 

 

"

QW-407.2 A change in the postweld heat treatment (see QW-407.1) temperature and time range the procedure qualification test shall be subjected to PWHT essentially equivalent to that encountered in the fabrication of production welds, including at least 80% of the aggregate times at temperature(s). "

 

As per the above clause the PQR is acceptable?. It does not meant PQR shall be essentially equivalent within 80% of actual production PWHT?. Since the manufacture done 60 minutes and 720 minutes, and the production PWHT comes in between holding time (108.6) the PQR will be acceptable?

 

 

Thanks & Regards
Muhammed Ibrahim PK

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José Juan Jiménez Alejandro

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Dec 8, 2021, 10:20:47 PM12/8/21
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First of all Greetings! Talk to your Authorized Inspector assigned to your company, if the container is going to be stamped, this indicates that your company has a Contract with an Authorized Inspection Agency (AAI) and that inspector is responsible for giving you that Technical support, if it is not doing it, Change the Inspection Agency.

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james gerald

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Dec 8, 2021, 10:20:50 PM12/8/21
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I suppose according to ASME SecIX 2 PQR can be combined provided all essential variables are same except one say in your case PWHT time


pgos...@rogers.com

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Dec 8, 2021, 10:49:10 PM12/8/21
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Yes James,

 

That’s possible, however from my experiences, I’ve seen combination PQRs always puzzle the Independent Inspectors, unless things are explained in a proper way. During our learning days in BHPV , L&T often we used to be queried by the TPIs, on combinations PQRs for PWHT and various other problems. However proper explanations of the code clauses  would often solve problems.

 

Thanks.

 

Pradip Goswami.P.Eng, IWE.

Cell/Whasapp:1-905-9793232

 

From: 'james gerald' via Materials & Welding <material...@googlegroups.com>
Sent: December 8, 2021 8:52 PM
To: material...@googlegroups.com
Subject: Re: [MW:32650] RE: 32639] PWHT soaking time for impact testing applicable vessel

 

I suppose according to ASME SecIX 2 PQR can be combined provided all essential variables are same except one say in your case PWHT time

 

On Wed, 8 Dec 2021 at 11:40 pm, pgos...@rogers.com

By the law of rationales , you should accept this combination of   PQRs. Why, as explained below:

 

Your calculated time for soaking is -108.6 minute. 80% of that time is:- 108.6x 0.8= 86.88 @ 87 minutes.

  • Vendor submitted PQR No1, is for 60 minutes
  • Vendor submitted PQR No2, is for 720 minutes. 720 minutes of soaking time is well over the requirements of 89 minutes as per the above calculations.

 

In fact, vendor had submitted both the PQR’s to safeguard the 87-minute requirement, as PQR No1 was for 60 minutes and did not meet the cut off requirements of 87 minutes. Hence, they substantiated the Sec IX requirements with the PQR of longer soaking time, i.e., 720 minutes.

 

In fact, the PQR with 720 minutes meet the requirements of 108.6 minutes of PWHT time. If I would the welding engineer or approving inspection engineer, I would have asked the PQR 1-(60 minutes) to be removed from the dossier, so as to avoid the confusion.

Since vendor had submitted both PQRs and if they want to retain both in the documentations,  ask for a clarification note in the above-mentioned justification to close the issue.

Also, you’ve to make sure that both PQR1 & PQR2 meet specifically charpy impact & hardness( if applicable)  in addition to the other mechanical test.

james gerald

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Dec 8, 2021, 11:28:01 PM12/8/21
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I agree sir but there may  be some reasons like varying thickness or other essential variables in addition to PWHT TIME for combining zPQRs else as you mentioned in your first mail one pqr is suffice



Paresh Patel

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Dec 8, 2021, 11:38:43 PM12/8/21
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Both pqr required to support the wps as to fulfill impact requirement as per Mr. James e-mail and the justification as per Mr. Pradips first e-mail.


To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/1303942843.99494.1639023445909%40mail.yahoo.com.

james gerald

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Dec 9, 2021, 4:56:57 AM12/9/21
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Inline image


Thanks & Regards

J.Gerald Jayakumar




Muhammed Ibrahim PK

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Dec 9, 2021, 4:56:58 AM12/9/21
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Dear Mr. Pradeep goswami,

As per the statement at least 80% meant minimum or it should be at least 80% closer to actual production PWHT? The statement in sec IX is "essentially equivalent to that encountered in the fabrication of production". 

Suppose I have done a PQR of 6 Hours and the impact test passed. If I am using same PQR and doing PWHT of 1 hour in job, what is the guarantee that the impact will pass in PTC?. We need to simulate the production condition of at least 80% closer to PQR and impact test?.


image.png


Thanks & Regards
Muhammed Ibrahim PK

james gerald

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Dec 9, 2021, 5:11:20 AM12/9/21
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As you increase the soaking time at particular temperature then Grain size will increase. AS per Hall-petch equation and theory, Finer grains produce Good charpy Impact properties and strength.

In Aramco specification the reverse of ASME Sec.IX is mentioned for soaking time as it will affect the Hardness.

Thanks & Regards

J.Gerald Jayakumar


Muhammed Ibrahim PK

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Dec 9, 2021, 5:42:48 AM12/9/21
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Dear Mr. james,

So as per your opinion one longer PWHT PQR (12 hr) will prove impact property at 1 hr to 12hr in job?

Reg,
Ibrahim

image.png

james gerald

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Dec 9, 2021, 6:10:30 AM12/9/21
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PWHT PQR(12 hr) will have less Charpy impact properties when compared to PWHT PQR(1hr)

Thanks & Regards

J.Gerald Jayakumar


james gerald

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Dec 10, 2021, 6:01:14 AM12/10/21
to 'james gerald' via Materials & Welding
Ibrahim,

Just to share.

ASME Sec VIII Div.I provides when you decrease the PWHT temperature you can increase the soaking time, same effect

Inline image


Thanks & Regards

J.Gerald Jayakumar


Mohd Siraj

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Feb 7, 2022, 4:18:15 AM2/7/22
to Materials & Welding
yes, acceptable, there is ASME interpretation.

I try to attach it but was not able to attach it.

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