Stainless Clad Removal

[dmyette]

We are doing repairs on a pressure vessel which is made of a carbon steel and is lined with 316L cladding. The cladding has experienced a significant amount of stress corrosion cracking and therefore needs to be removed. Currently we are grinding/gouging to remove the clad but it is very time consuming. Does anyone know an easier, more time efficient method for removing stainless cladding from plain carbon?

 

[metengr]

If this is weld deposited cladding, you are going about it the best way one can in this situation. I have seen portable milling machines on tracks, but this could be costly and time consuming.

Another option is to consider replacing whole sections of the vessel using a series of flush patch plates (remove sections of the vessel that contain the defective cladding and install replacement vessel plates that are full penetration welded to the existing vessel wall). Once the flush patch plate is installed, you can deposit new weld cladding from the ID surface of the vessel and tie it in to the existing cladding.

 

[EdStainless]

How thick is the shell? How thick is the clad?
How was it applied? (weld, subarc, explosive bond, rollbond)
What are you going to do after striping?

I hate to say it, but if you really need all of the stainless removed then you are doing it right.
I just wonder if you need to do this good of a job?

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[dmyette]

The shell is 18mm thick.
The clad is 3mm thick.
The clad was applied by a hot rolling technique.
After we strip the clad from the carbon steel we will overlay the carbon steel with a layer or 309 then a layer of 316.

The cracking is severe, with approximately 60% of the area experiencing cracking and 90% of the cracking is through to the carbon steel. The area which is experiencing the cracking is a hemispherical head that has a 17'-3" diameter.

The pressure vessel will contain black liquor which is at a concentration that will eat through carbon steel in a matter of weeks if exposed to it.

 

[StoneCold]

I am not an expert on the costs in this case but wouldn't you be money ahead to replace the vessel with a new one made of 2205. You could probably get away with a thinner shell and it would be a better alloy for the job.

Regards
Stonecold