How to prevent rust on metals
This virtual course, which lasts 21 teaching hours, presents the main techniques currently used for the prevention and control of corrosion, as a starting point for the subsequent selection of the most appropriate protection options for each case. The participant’s dedication is approximately 15 hours per week.
This course is aimed at heads and managers of maintenance and production areas, inspectors of industrial installations and equipment, as well as professionals in loss assessment, professionals from different branches of engineering and university professors.
What products are used to protect metals from corrosion?
Corrosion is formed when a metal atom is oxidized by a fluid, causing the loss of material on the surface of the metal. The resulting loss of material reduces the wall thickness of carbon steel components and low alloy steels, which are affected by general corrosion and become more prone to mechanical failure.
Although generally detectable by close visual inspection, these cavities can grow deep enough to perforate a pipe wall completely. Pitting corrosion can also facilitate the initiation of cracks in stressed components. The environment with high chloride concentrations, including those created by the evaporation of salt water droplets deposited on the surface of the metal, is conducive to pitting corrosion, especially at elevated temperatures.
When examining metal pipes for pitting corrosion, look for reddish-brown iron oxide deposits, as well as possible cavities that may have formed on the surface of the metal.
Types of corrosion
If acid and/or corrosive gases are generated in the production process, such as hydrogen sulfide (H2S), sulfur dioxide (SO2), ozone (O3), nitrous oxides (NOx), ammonia (NH3) and derivatives, chlorine (Cl2) and derivatives, hydrofluoric acid (HF) or similar, they can penetrate the electrical rooms through doors, windows, ventilation holes, cable glands, creating a highly corrosive indoor environment that affects the installed instrumentation.
Corrosion attacks the connection terminals, pin connectors, IC sockets and the pins of the integrated circuits themselves, which leads to increased resistance to the passage of current through these elements, falsifying the actual readings and producing an overheating effect on the various elements, leading to failures. These failures generate considerable maintenance costs and even more costly production losses.
The best current technology for the removal of corrosive gaseous compounds, in this concentration range, is chemical filtration in air treatment units, where the filtering material is adsorbent spheres impregnated with chemical reagents.
How to avoid corrosion
Corrosion is the natural enemy of metallic steel structures. Literally: it is caused by factors in nature such as oxygen and accelerated by others such as chloridium: water and salt.
However, it is a mistake to assume that this represents a negative or a reason to avoid using the material. Steel can be prepared to resist corrosion. There are different processes to do so – these are three of them.
Generally, there are three basic processes to prevent corrosion in metallic structures: coating the structure with anti-corrosion paint, using corrosion-proof steel, or simply avoiding the environmental factors that cause corrosion.
Susceptibility to corrosion is essentially due to exposure to oxygen and moisture. The rate of the process is greatly increased in the presence of other corrosive agents, such as chlorine ions. To protect the material – and thus overcome one of its most basic limitations – the following processes can be carried out.