pickling/passivation after fabrication completed

[AspenMech]

Hi all,

What would be the normal internal cleaning procedure for vessels after fabrication? when is pickling or passivation required?

Thanks,

 

[EdStainless]

So, I will presume that this a 300 series SS vessel that you are talking about.
Is there any internal heat tint from the welds?
If so, then you screwed up your weld purging and you will need to pickle.
Nitric+HF is the only thing that will remove the heat tint.
There are pastes, swabs, and electrochemical methods of doing this.
Then you will need to rinse thoroughly with water multiple times.
The final rinse should be with clean (DI) water.
Then when you are done with all work and inspection and will not be touching the inside again you can passivate.
There are various options depending on what your customer requires and what specs are involved.
Then again multiple rinses finishing with DI water.
And then dry it well.

 

[mfgenggear]

OP
a tip passivate after final inspection but prior to ndt.
follow the procedure of AMS 2700