when to do PWHT for cladded vessel

[inammanj123]

If a vessel is under PWHT and there is a S.S cladded plate also. How cladded is done? i mean after rolling of plate by vessel manufactuured or the mill will send the cladded plate?

PWHT for whole equipment will be after cladding or before cladding is applied?

 

[Geoff13]

I'm only aware that cladding can be done by the original clad plate manufacturer while it's still flat, using either roll bonding or explosive bonding. It would be a good idea to let the clad plate manufacturer know you'll be PWHT'ing the completed vessel so they can incorporate that into their planning.

For cladding that would be PWHT'd in the completed vessel I've always seen an L grade used for austenitic stainless (i.e. use 304L in place of 304) to minimise the carbide precipitation during PWHT.

The equivalent to cladding for a completed vessel would be weld overlay. This may be done after PWHT (i.e. for P1 materials) but other base metals could require the weld overlay to be done before PWHT. I would guess weld ovelay would be more expensive than cladding for new construction.

 

[cap1a79]

It depends on whether the process is weldoverlay or rolled clad plate.

1) For the process of weld overlay, you need to perform PWHT after 1st layer is deposited. Refer to below link, table 4. (There is filler metals information for different clad metal)

https://www.asminternational.org/do...yNow.pdf/152a4ca7-ca11-4a48-ad7d-4c2b2c39bd16

https://www.eng-tips.com/viewthread.cfm?qid=435339

2) If it is rolled clad plate, PWHT shall be applied after bonded. As there is sensitization issue (carbon precipitation of SS), the cladded SS shall be stabilized grade. (ex., SS 321, SS347)

Refer to ASME Sec VIII-1, UCL-34 and below post as well.

https://www.eng-tips.com/viewthread.cfm?qid=435339

Lee SiHyoung,
WorleyParsons Oman Engineering,