Hydrogen Bakeout?

[lcmechengr]

I have several used vessels that were previously in hydrogen service that a client has aquired and would like to return to service. Per API 941, with the expected design temps and partial pressures of Hydrogen, all of the vessels are fabricated from metals that are resistant to High Temperature Hydrogen Attack. We have performed an internal visual inspection and there are no visible signs of HTHA. I was also going to perform Mag Particle testing on some of the welds and HAZ. Is there reason to perform more NDE than this? I have had someone recommend preforming a Hydrogen Bake out to cause any defects to surface. Is this standard practice? Thanks for any insight.

 

[metengr]

I was also going to perform Mag Particle testing on some of the welds and HAZ. Is there reason to perform more NDE than this?

Based on what you have stated above, no.

I have had someone recommend preforming a Hydrogen Bake out to cause any defects to surface.

This would only be used in the event you needed to perform weld repairs on a damaged vessel.