Corrosion Classes

Corrosion classes refer to how different environments affect materials. The classes range from C1 to C5, where C1 represents the mildest environment and C5 the most severe.…

Corrosion Classes

Corrosion classes refer to how different environments affect materials. The classes range from C1 to C5, where C1 represents the mildest environment and C5 the most severe. When we talk about corrosion, we refer to the process that gradually degrades metal over time. In other words, the corrosion class indicates how durable steel is in a given environment. In the table below, the classes are listed along with examples of typical environments.

Corrosion rates vary depending on both the environment and the type of metal in question. The table below provides general corrosion rates in µm over a 20-year period.

The figures in the table are indicative and will depend on the specific environment, material alloy, and other factors.

The key point to remember is that corrosion classes indicate the severity of the environment, not how suitable a particular material is. Material suitability is typically expressed in terms of how many grams of material corrode per square meter per year.