This standard specifies the acid pickling of aluminium and aluminium alloys. It is applicable whenever referenced. Purpose of process Pre-treatment before penetrant testing/penetrant inspection. Pre-treatment before anodizing. Final treatment for parts prior to adhesive bonding application. Final treatment before welding or brazing. Pre-treatment before chemical milling. Final treatment for parts prior to painting application. Pre-treatment for parts prior to surface conversion coatings. Desmutting (Blanchiment)@ after alkaline etching or acid pickling.