In our opinion, stainless steel pickling is the most important treatment of the three listed.
Pickling means a treatment capable of completely removing the scales of oxides that form on the surface of the welded piece (tig-mig-electrode), as well as the thin layer of chromium-depleted steel due to the alterations due to the heat of the welding.
Industrial chemical pickling systems involve the use of baths in which the pieces are immersed and left for a period ranging from 30 to 50 minutes (variable time based on temperature and based on the type of oxide to be carried).
Pickling pastes and gels are also available which are applied to the area to be pickled by means of brushes or spray pumps and then rinsed with cold and pressurized water.
The advantage of pickling by means of gel or paste is that of being able to treat even very large objects and not having to prepare a large and difficult to manage bathroom with very high costs.
The most commonly used mixtures for making pickling baths and gels are the mixtures of nitric acid and hydrofluoric acid.
On the market there are mixtures without nitric acid, with a better olfactory impact.