In AISI 316L stainless steel, chromium is present between 16 and 18%, nickel between 11% and 14% and molybdenum up to 3%. In stainless steel AISI 304, there is a quantity of chromium between 18 and 20% and of nickel between 8% and 11%. These are two types of alloys in austenitic stainless steel, ie with high percentages of binders.

EiQ Industrial is in any case able to offer electrical panels in steels different from the standard ones thanks to the design team able to study customized solutions based on Steel Design and Fabrication needs. Materials 1.4541, 1.4571 and 1.4435 can be considered resistant to intercrystalline corrosion.

Pitting corrosion

In the case of this corrosion, the passive layer is broken only at certain points. The consequence is that pits or holes form on the surface. Pitting corrosion is mainly caused by halogen ions, especially chlorine ions. It can be strengthened primarily by water and wastewater, often related to the presence of chlorine and chloride ions.

Galvanic corrosion is very common and is created when metallic materials of different potential come into contact in the presence of an electrolyte. In this case, the less noble metal is attacked by the electrolyte and dissolves.

The importance of corrosion is proportional to the amount of electricity flowing in this galvanic element. This type of corrosion is very common. One of the best known examples of this corrosion is the connection of steel and stainless steel flanges. This type of corrosion also occurs in the case of screwing cast iron flanges with stainless steel screws.

Cavernous occurs when the passive layer of stainless steel is destroyed, for example by the presence of corrosive products combined with a lack of oxygen. Therefore, this type of corrosion is common in narrow slots and small cavities, for example under joints, under the heads of nuts.

An example is that of the gas cap in the fermentation tanks, inside which there is a corrosive product in the form of a fermentation gas, but in which the oxygen is totally lacking. Special attention is needed to avoid the formation of such corrosion as shown in Steel Design and Fabrication.

Cleaning and maintenance

For the removal of fingerprints, a solution of dishwashing liquid is generally sufficient. Some manufacturers of cleaning products offer special products with a better cleaning effect thanks to the addition of a maintenance component. In the case of stubborn soiling, it is possible to use standard cleansing milk, which also combats limescale and discolouration. After cleaning, the surface is rinsed with clean water.