Is PWHT required for Cladding ?

[nktqc]

Hi Friends,

We are doing cladding on CS materials , having thickness more then 19.05 mmm.

There is PWHT requirement for Butt weld but "Is PWHT required for Cladd welding also"?

If required then which code is recommending for this.

Kindly help !

Thanks

 

[metengr]

The applicability of a construction code must first be determined to decide on necessary preheat and past weld heat treatment requirements. What is the component being cladded?

 

[nktqc]

Its Pipe , fittings and flanges for sour service.

 

[metengr]

What is the construction code you are working under? B31.1 Piping Code, ASME Section VIII, Div 1 or other???

 

[nktqc]

Sorry for late reply

Its B 31.3 , we are following.

 

[jbeckhou]

what type of clad material are you using? I believe NACE requires PWHT if being used for H2S service.

Petrotrim Services

http://www.petrotrim.com

 

[nktqc]

We are doing Alloy 625 and Alloy 825 cladding.

 

[metengr]

At 19mm base metal thickness, PWHT will probably be required to keep the base metal hardness below 22 HRc scale for NACE compliance. What you can do is have a weld coupon completed and evaluate the base metal heat affected zone hardness. If your carbon equivalent (CE) is low and you use an elevated preheat, you might be able to keep the BM hardness below 22 HRc scale.

 

[nktqc]

well , we had qualified WPS for both cases ( With PWHT without PWHT) including hardness. Earlier we did some projects in which there was NO requirement of PWHT for cladding but there was requirement of PWHT for butt weld ( Welded by Alloy 625 ) and we did.

Issue is , for cladding which code is recommending for PWHT ?

and IT is Required if we are meeting the hardness requirements ?

 

[metengr]

Seek and ye shall find-

ASME B31.3 323.4.3 Cladding and Lining Materials....

(d) Fabrication by welding of clad or lined piping
components and the inspection and testing of such components
shall be done in accordance with applicable
provisions of the BPV Code, Section VIII, Division 1,
UCL-30 through UCL-52, or the provisions of Chapters
V and VI of this Code, whichever are more stringent.

 

[nktqc]

Thanks metengr

I got following -

(a) Vessels or parts of vessels constructed of base material
with corrosion resistant integral or weld metal overlay
cladding or applied corrosion resistant lining material shall
be postweld heat treated when the base material is required
to be postweld heat treated. In applying these rules, the
determining thickness shall be the thickness of the base
material.

When the thickness of the base material requires postweld
heat treatment, it shall be performed after the application
of corrosion resistant weld metal overlay cladding or
applied corrosion resistant lining unless exempted by the
Notes of Table UCS-56.

 

[nktqc]

addition to above - from UCS56

(c) for welded joints of all thicknesses if required by UW-2, except postweld heat treatment is not mandatory under the conditions specified below:

(5) for corrosion resistant weld metal overlay cladding or for welds attaching corrosion resistant applied lining (see UCL-34) provided
preheat to a minimum temperature of 200°F (95°C) is maintained during application of the first layer when the thickness of the
pressure part exceeds 11?4 in. (32 mm).