STEEL’S RESISTANCE TO CORROSION

All metals, with the exception of the most prized like silver and gold which are found in nature in their natural state, are extracted from their ores. Metals therefore have a tendency to remain in a stable state, which represents each metal’s original state that corresponds to its oxide state.

Corrosion is essentially an electrochemical reaction that takes place between the metal and its surrounding environment.

In general it is difficult to predict how a certain metal will react over time when placed in certain environments. Thanks to its chemical composition, stainless steel is able to self-passivate and protect itself even in the most aggressive environmental conditions.

The following factors contribute to corrosion:
– the frequency of exposure to an aggressive environment
– exposure to extreme temperatures
– the velocity of liquid’s contact to the metal
– a metal’s surface finish

TYPES OF CORROSION

Pinhole corrosion: localised ruptures of stainless steel’s passive layer, caused by electrolytes that are rich in chlorides or sulphides
Cavernous corrosion: electrolytes that contain a high percentage of chlorides that are enclosed in a poorly-designed structure tend to lead to an excessive accumulation of chloride ions. This leads to the progressive acidification of the environment, which causes the breakdown of the passivated layer.
Intergranular corrosion: can occur in welded areas due to low levels of chromium
Stress corrosion cracking: this type of corrosion affects the entire surface of the metal as it is attacked by a corrosive element. On a micro-graphic scale it corresponds to a loss of uniform thickness and weight.

In general the best antidote to corrosive phenomena is offered by austenitic steels, which have a particularly resistant passive film. In order to avoid potential corrosion, it is important to properly select the material to be used depending on its function and its purpose. It is also helpful to follow certain precautions during the production phase and to avoid exposure to less quality metals, such as common steel, during the stocking phase, as well as production, and installation. Sometimes cleaning stainless steel simply requires soap and water or soap and baking soda. In cases where there is a lot of dirt present, you may need to undertake pickling and decontamination, using appropriate pastes on localised areas.

As part of its wide offering of services, Inoxstyle offers the most effective treatments to fight corrosion, including professional treatments of polishing and pickling, the intensive cleaning that removes unwanted surface layers.

You may also be interested: