16Mo5+1.4002 cladding

[Titirli123]

Hi everyone!

We have a situation on a pressure vessel made of 16Mo5+1.4002 (85mm+5mm cladding) where the NDT company have encounter cracks on circumferential welds.

Our client agree only to remove the cracks by grinding but without any further welding.

The medium is hydrocarbons with hydrogen.

Does anyone encounter this problem before?

Thank you!

 

[pradipgoswami]

Hi ,
This vessel is constructed of C-0.5Mo steel with Ferritic(405) SS. cladding. I'm assuming cracks are on the wetted surface (FSS).If the depth of is very shallow, the ground area is rounded off and blended well, and client regularly monitors further damage mechanism, a deviation from regular weld repair may be thought of. Such deviations has to be accepted by a licensed engineer.

The other option is to proceed for regular weld repair. Weld repair should be done with austenitic SS, 309L/Inconel 182 electrodes. A properly executed weld repair may last for many years and is always a good option in hydrogen service.

Pradip Goswami,P.Eng.IWE
Welding & Metallurgical Specialist
ca.linkedin.com/pub/pradip-goswami/5/985/299

 

[metengr]

Where are the cracks - on the ID or OD surface of the vessel? Removal of the cracks is required. Further evaluation to decide if the excavations require weld repair is either a fitness for service (FFS) approach or fracture mechanics analysis.

 

[Titirli123]

Hello.

Thank you very much for your opinions.

The cracks were on the inside, on the cladding side.

Finally, they remove the cracks, but they didn't want to weld.

I think they will monitor the evolution of the vessel during operation.

 

[r6155]

Is it a new pressure vessel?
Are cracks only in one circumferential weld?

Regards
r6155