625 cladded pipe welding - Root and Hot padd with NiCrMo3 and remaining with CS electrodes

[Anil Anlei]

In order to weld (pipe to pipe) CS pipe with Inconel 625 clad, can we use root and hot pass with NiCrMo3 Gtaw and remain with CS electrodes (SMAW or SAW). The design code is ASME B 31.3 @018 Edition.

 

[weldstan]

Not a good idea if you want to avoid cracking of the carbons steel weld metal's first pass over the NiCrMo3.

 

[SJones]

No - you will need a buffer layer between the 625 and the carbon steel. The buffer layer will be prone to solidification cracking, and it is unlikely that the weld will meet hardness restrictions.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[DekDee]

I do not have a lot of experience with overlay so would be interested in weldstan and sjones thoughts.
If you have CS pipe with overlay would it not be CS electrode for root and hotpass and possibly NiCrMo3 for filler ?
Or is the cladding internal and not external ?

 

[SJones]

@DekDee
It is taken that the OP is referring to a single sided girth weld with the CRA cladding on the inside.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.

 

[DekDee]

SJones - thanks for the response.
Cheers

 

[weldstan]

Complete the joint (root, hot pass and fill) with E/ER-NiCrMo3. This was common practice in the past 50 years of my experience.

 

[SJones]

Indeed. Many have tried the three filler, approach, and it clearly hasn’t gained any lasting support.

Steve Jones
Corrosion Management Consultant

http://www.linkedin.com/in/drstevejones

All answers are personal opinions only and are in no way connected with any employer.