Painting of stainless steel castings 1

[prc]

We have seen some black marks on the surface of smooth white stainless steel casting (AISI 316)-10 inch valve body)in middle east. To avoid this corrosion marks, propose to paint the valve body with epoxy +polyurethane paint. What should be the surface preparartion and nature of primer paint(etch primer as in csae of aluminum?)to be used to get a reliable painting ?

 

[CoryPad]

Abrasive blasting followed by paint is the usual method. Here is a guide:

http://www.bssa.org.uk/topics.php?article=119

 

[prc]

Thanks Corypad.

 

[babouic]

Here under is the surface preparation recommended by Total in GS EP COR 350

Stainless steels shall be segregated, carbon steel supports for storage shall be systematicallypainted, and lifting equipment shall prevent iron contamination.
Stainless steel surfaces to be coated shall be etched or degreased and blast-cleaned with a
non-ferrous and chlorine-free abrasive.

The blast cleaning procedure to be submitted to Company shall include:
• Abrasive composition to obtain a surface roughness of Ra = 10 microns (8 microns
acceptable locally)
• Dust level (maximum level 2 maximum according to ISO 8502-3)
• Substrate contamination checks. Ferrous contamination/direct colorimetry method using
Prussian blue (potassium ferricyanide) - No surface pollution is acceptable