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Up Topic Welding Industry / ASME Codes / PWHT method
- - By Boon (**) Date 03-05-2013 15:03
We are working on a project using crome-molly plates. If fabrication code is according to ASME B31.3, must PWHT be perform if customer didn't specify it but is a recommendation by plate manufacturer?

I think some would say follow the WPS but we do not have a current WPS, need to start working on new procedure test and question is whether to include PWHT.

I did a search but could not find answers on how a PWHT is being carried out.
1. Can there a time delay between completion of welding till the start of PWHT?
2. How many heating methods are generally available for PWHT?
3. PWHT is applied only to the weld or completed product?

Best regards
Boon
Parent - - By bert lee (**) Date 03-05-2013 15:40
material pno please?
Parent - - By Boon (**) Date 03-05-2013 15:55
A204,  8 mm, 10 mm thick.
Parent - By Joey (***) Date 03-08-2013 10:09
The answer is in B31.3 Table 331.1.1 Requirements for Heat Treatment
Parent - By js55 (*****) Date 03-05-2013 20:07
1) yes
2) furnace, induction, and electric resistance come to mind
3) the weld, the HAZ and some of the unaffected base metal if you do locals. If you do furnace its moot.
Parent - - By G.S.Crisi (****) Date 03-07-2013 22:56
ASME B31.3 is the Code for design and erection of chemical plants and refinery piping. You're talking of plates.  
How does B31.3 apply to plates?
Giovanni S. Crisi
Sao Paulo - Brazil
Parent - By 803056 (*****) Date 03-08-2013 05:42
The code, B31.3, includes the conditions for which post weld heat treatment is required.

The customer has already "told" you what the requirements are when they specified the applicable construction code. Ypou should ask the design engineer for additional information if you can't figure out the requirements based on the information provided by the drawings and project specifications.

The design engineer should be able to tell you if PWHT is necessary since the need for PWHT should have been considered during the design stage of the project.

Al
Parent - - By ssbn727 (*****) Date 03-08-2013 11:10 Edited 03-08-2013 11:32
These are some examples Professor;

Blanks are flat plates that get sandwiched between flanges to block flow...
Main & intermediate anchors...
The fabrication of certain types of expansion joint systems...
A wide variety of piping supports as well as piping guides.

With respect to PWHT, one has to determine which category of piping is being erected such as Category "N" or Category "M" in order to select the proper details such as time & temperature, etc... It's all there in B31.3 (Joey & Al beat me to it:wink:)... One needs to find it inside, and then properly apply the ASME B31.3 Process Piping Code to the job as per contract specifications...
Also, make darn sure the plate component that's being welded together applies to B31.3 and not ASME BPVC, Section VIII, Division 1.:eek::yell::lol::roll::roll::roll::wink::cool:

Respectfully,
Henry
Parent - By 803056 (*****) Date 03-08-2013 14:53
Pipe supports, hangers, supporting members, etc. are designed and fabricated to AISC requirements, which incorporates AWS D1.1 for structural components made of carbon and low alloy steels. Miscellaneous structural supports are not usually subjected to stress relief.

Al
Parent - - By G.S.Crisi (****) Date 03-08-2013 20:34
I insist.
B31.3 is the Code that rules chemical plant and refinery piping. It says when and how to PWHT piping welds.
A 204 is a low alloy steel (carbon molybdenum) plate. It doesn't fall under B31.3. As Al said, the variety of items made of steel plate that Henry pointed out are governed by AISC and are not subject to PWHT.
What I don't understand is the reason for using a low alloy (carbon molybdenum) steel plate to make pipe suports, anchors and guides, things that are usually made of plain carbon steel.
If A 204 were used for pressure vessels, it had to be PWHT for thicknesses 3/4 of an inch and above. In his case, the thickness is 10 mm, roughly 3/8 inches. 
Conclusion: Boon doesn't need to worry about PWHT of his A 204 plate.
Giovanni S. Crisi
Parent - - By ssbn727 (*****) Date 03-08-2013 22:03
Especially if it was just a "Recommendation by plate manufacturer." Which is not the same as a "Requirement."

Respectfully,
Henry
Parent - - By ssbn727 (*****) Date 03-13-2013 02:13
Btw, I should have looked earlier but hey nobody's perfect!:yell::twisted::eek::lol::twisted::cool:
I didn't previously check to see what standard falls under pipe hangers, pipe supports, etc... When I did, I was pleasantly surprised...

Pipe hangers, supports, etc. do indeed follow a specific set of standards known as MSS SP-58 2009, MSS SP-69 and it's associated standards as well...
So here are some links to them:

http://www.scribd.com/doc/87318949/73427823-MSS-SP-58-2009

http://www.scribd.com/doc/15741974/Pipe-Support

http://www.scribd.com/doc/73427823/MSS-SP-58-2009

Respectfully,
Henry
Parent - - By 803056 (*****) Date 03-13-2013 04:14
I stand corrected. I should have said the structural steel added to support hangers, etc. is design and fabricated per AISC. Oops!

Al
Parent - By ssbn727 (*****) Date 03-13-2013 23:54 Edited 03-14-2013 00:01
That's okay Al... Nobody's perfect including both you and I:lol::lol::lol::wink:

I think Boon wherever he went, is referring to blanks when he mentioned Plate and I also think that A-204 is really a typo for A-240 but then again this is only a guess on my part.

I do hope that Boon does rejoin the thread so that he can clarify some glaring questions regarding the specifics of his OP.:eek::lol::wink::cool:

Respectfully,
Henry
Up Topic Welding Industry / ASME Codes / PWHT method

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