Hi, I had a project to put brass vales in high pressure aluminium gas cylinders. If there was no "neutral" interface between the 2 materials the vavle would "weld" itself to the aluminium. It would rip threads out or tear the top of the cylinder off when it was removed!
We...
Max, Moist CO2 will form Carbonic Acid and attack common steels.
I would advise 316,309,310 SS, Monel, Hastelloy A,B,C or Monel for use with industrial CO2. Sorry, but steel will be corroded and fail eventually
Simon