The corrosion resistance of stainless steel rests on the formation of a very thin chromium oxide rich passive layer which only develops on metallic clean stainless steel surfaces.
Scale layers, welding colours and tarnish, ferritic impurities (e.g. abrasion), mechanical treatments (e.g. grinding, blasting etc.) inhibit the formation of a closed passive layer.
Only fully controlled pickled stainless steel surfaces and weld seams therefore guaran-tee full corrosion resistance of the material and in addition offer a decorative metallic appearance.
Chemical pickling processes
Depending on the requirements and the size of the workpiece the components to be pickled are immersed into pickling baths or the pickling medium is sprayed on the metal surface and rinsed off with conditioned (demineralized) water and passivated.
The pickling chemicals consist of acid mixtures effecting chemical removal on the top material layers in a range of 1-3 µm.
High-alloyed ferrous alloys, copper and copper alloys, nickel and nickel alloys, titanium and titanium alloys, niobium and niobium alloys