BS ISO 27831-2:2008

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Essential information to be supplied by the purchaser
   to the processor
5 Requirements
6 Standard cleaning methods
7 Non-corrosion-resisting steels, cast irons and pure irons
8 Corrosion-resisting and heat-resisting steels
9 Pretreatment of metals prior to powder coating
10 Cleaning and preparation processes
11 Aluminium and aluminium alloys
12 Copper and copper alloys
13 Nickel alloys
14 Titanium and titanium alloys
15 Magnesium alloy
16 Zinc-based alloys
17 Tin and its alloys
18 Tungsten alloys
19 Lead and its alloys
20 Zinc-, cadmium-, chromium- and gold-coated items
21 Pretreatment of metals prior to powder coating
22 Cleaning and preparation processes
Annex A (informative) - Maintenance of organic and vapour
        degreasing baths
Annex B (informative) - The control of acidity in vapour
        cleaning baths
Annex C (normative) - Method for the determination of
        oxidizable material in sulfuric acid
Annex D (informative) - Method for determining free acidity
Annex E (normative) - Selection of method of cleaning
        according to the tensile strength of the steel in
        zinc-coated steel items prior to chromate conversion
        coating
Annex F (normative) - Method M4
Bibliography

Describes 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.

This part of ISO 27831 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. However, many of the processes included in this part of ISO 27831 may be used for these operations at the discretion of the users of this part of ISO 27831.

This part of ISO 27831 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.

This part of ISO 27831 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).

This part of ISO 27831 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.