ISO 27831-2:2008 specifies processes for the cleaning of the surfaces of non-ferrous metals and their alloys to remove any irrelevant or unwanted deposits or other material at any stage of manufacture, storage or service and for the preparation of these surfaces for further treatment. It does not cover cleaning operations associated with the preliminary removal of heavy deposits of oil, grease or dirt accumulated during operational service, preparations for welding or the cleaning of electrical contacts.
It covers processes which are needed for the preparation of metal surfaces prior to the application of the following surface coatings:
- electrodeposited metal coatings;
- autocatalytic metal coatings (autocatalytic and displacement types);
- conversion coatings;
- anodic oxidation coatings;
- hot-dipped coatings;
- sprayed metal coatings;
- coatings produced by vitreous enamelling;
- coatings produced by physical vapour deposition of aluminium and cadmium;
- powder coatings.
It describes processes for carrying out the following treatments:
- degreasing;
- descaling;
- pickling;
- etching;
- de-rusting;
- chemical smoothing;
- chemical polishing;
- electrobrightening;
- electropolishing;
- fluoride anodizing (for cleaning magnesium alloys).
It relates the processes described above to the following metals:
- aluminium and aluminium alloys;
- copper and copper alloys;
- nickel alloys;
- titanium and titanium alloys;
- magnesium alloys;
- zinc-based alloys;
- tin and tin alloys;
- tungsten alloys;
- lead and lead alloys;
- zinc-, cadmium-, chromium- and gold-coated items.
