POST HEATING OR dehydrogenation heat treatment

[NIKHIL THOMAS JOY]

Dear friends,

Greetings of the day,

I would like to check the post heating details for pipe welded joints for alloy materials.

Please share in which code its available to refer.

My main concern , there is any need to mention post heating in wps or pqr.

if yes, in which code its mention.

Waiting for experts advice.

 

[Jamie Reyes]

PWHT is determined by the thickness of the material. Depending on how thick the material is will determine if Post weld heat treat is needed. To refer you to a certain code without knowing the code of Construction would only be guessing. There is more caveats involved, but without knowing more information, this  is as far as I can go. Refer to the correct code of construction for the fabrication involved.

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Regards,

Jamie Reyes

J.R. Machine Company, Inc.

[NIKHIL THOMAS JOY]

Sir,

Now i'm doing POST HEATING ON WELD AFTER WELDING AT 350deg cel. for 30 min.  But could you tell me which code it mention.

Waiting for experts response.

BEST REGARDS,

NIKHIL THOMAS JOY

IWI LIMITED 

ADNOC-WHRP

0544975526

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[luis carlos greggianin]

Normally you could find this informations in Engineering Recomendations, Project Technical Instructions, or Recomended Practices, like API RP. 

Regard

L.C. Greggianin

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[atul khatri]

I am sorry , Perhaps I misinterpreted your query with simple PWHT instead of Post heating / dehydrogenation.

Regards,

Atul Khatri

Principal Engineer- Piping

Haldor Topsoe India Pvt. Ltd

https://www.linkedin.com/in/atul-khatri-95ba3667

On Mon, Oct 26, 2020 at 10:17 AM atul khatri <atul....@gmail.com> wrote:

Dear Mr. Nikhil,

If your concern  is related to process piping then refer to table 331.1.1 of ASME B 31.3. It's based on control thickness.

If you want the specific answer to your query then please share..

-Constructional code

-Material

 -Thickness of pipe   

- Fluid service

Please check if your client  or Licensor is having any stringent requirements ,as it can supersede the codes requirement as well.

And Yes, Post weld heat requirement shall be mentioned in WPS / PQR. Refer ASME IX. It's an essential variable. Refer QW-407

Feel free to discuss in case you need further assistance.

Regards,

Atul Khatri

Principal Engineer- Piping

Haldor Topsoe India Pvt. Ltd

https://www.linkedin.com/in/atul-khatri-95ba3667

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAJxkuiU1dwdP%3DbozD2kk%2B2-CP623VZkwdMhaPr-ZGWAncxbXRA%40mail.gmail.com.

[atul khatri]

Dear Mr. Nikhil,

If your concern  is related to process piping then refer to table 331.1.1 of ASME B 31.3. It's based on control thickness.

If you want the specific answer to your query then please share..

-Constructional code

-Material

 -Thickness of pipe   

- Fluid service

Please check if your client  or Licensor is having any stringent requirements ,as it can supersede the codes requirement as well.

And Yes, Post weld heat requirement shall be mentioned in WPS / PQR. Refer ASME IX. It's an essential variable. Refer QW-407

Feel free to discuss in case you need further assistance.

Regards,

Atul Khatri

Principal Engineer- Piping

Haldor Topsoe India Pvt. Ltd

https://www.linkedin.com/in/atul-khatri-95ba3667

To view this discussion on the web visit https://groups.google.com/d/msgid/materials-welding/CAJxkuiU1dwdP%3DbozD2kk%2B2-CP623VZkwdMhaPr-ZGWAncxbXRA%40mail.gmail.com.

[udaya bhaskar]

FYI,

Check

 QW-407

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With Regards

Udaya bahaskar.D

+919676270121

[NIKHIL THOMAS JOY]

Mr.Udaya bhaskar,

Sir, QW-407 Gives description about PWHT. There is no mention about post heating or DHT.

BEST REGARDS,

NIKHIL THOMAS JOY

IWI LIMITED 

ADNOC-WHRP

0544975526

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[Jamie Reyes]

 I believe I misunderstood your query. When mentioning “post heat,” I believe you should be referred to “preheat maintenance.” If so, this is a nonessential variable in most weld processes and is not needed in order to qualify weld procedures per ASME IX. Although, not to say that the code of construction doesn’t require preheat maintenance. Refer to ASME IX per weld process used and the code of construction for which the fabrication was designed under. 

QW-406.2 A change in the maintenance or reduction of preheat upon completion of welding prior to any required postweld heat treatment.

 In closing, if pre-heat maintenance was utilized prior to any required post weld heat treatment, then simply list the method used. If pre-heat maintenance was not utilized prior to any required postweld heat treatment, then simply state “NONE,” considering if the variable is listed as “nonessential,” in accordance with the weld process used during qualification. (Ambient room temperature can also be noted as well, in place of “NONE” if that is the case. Cheers.......

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[George Dilintas]

There is no post-heating variable among the essential and not essential variables. Post  -heating is mentioned in QW-409.15 which is related to the electrical characteristics of Resistance Welding

There is Preheat Maintenance (read QW-406.2 to understand the meaning) which is a non-essential variable.

There is PWHT (read QW-407.1 & 407.2). Post heating to remove hydrogen should be treated as PWHT

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Dr. Georgios Dilintas,

Dipl. Ing. In Aeronautic and Space Engineering

Ph.D in Mechanics of Solids - Computational Mechanics

A.I.S, A.N.I, IRCA Lead Auditor

Welding, Stress Analysis, Corrosion, QA/QC, Failure Analysis, Risk Analysis