PICKLE AND PASSIVATE STAINLESS STEEL

Pickling is the process that uses chemical means to remove oxide flakes that are formed during hot processing in the presence of atmospheric oxygen: the final result is a product with a regular surface and uniform grey colour, in preparation for any subsequent passivation or electropolishing treatment.

Pickling is the simplest and cheapest method to obtain a decontaminated and homogeneous stainless steel surface that can guarantee the characteristics for which this alloy was used. The formation of the particular protective film that distinguishes stainless steel can only be formed correctly in the absence of the oxides and contaminants that pickling eliminates. Contaminated stainless steel that has not been pickled will corrode sooner or later - guaranteed!

Pickling and passivation treatments can be performed in accordance with ASTM A480 and ASTM 967 standards by immersion or spray using gels or liquids, with products completely free of or containing nitric acid, according to the customer's specifications.

DECONTAMINATION
The decontamination treatment eliminates ferrous and other metal contaminants from the surface of the stainless steel. The presence of these foreign materials on the surface interferes with the formation of the protective film, favouring potential corrosive triggers. The immersion or spraying of special solutions allows the complete removal of these pollutants without altering the original appearance of the product; compared to pickling, there is practically no material removed.

Decontamination always has a beneficial effect on the stability of the passivation of stainless steel and for this reason it is often improperly defined as passivation. Decontamination can be verified with specific reagents, compliant with the reference ASTMs, or with a cycle of wetting repeated over 24 hours .