Magnelis® steel outperforms galvanised steel in soil

The complexity of corrosion mechanisms has made it difficult to establish norms and standards for solar steel structures in soils. Thanks to its extensive research, including laboratory and outdoor testing over a number of years, ArcelorMittal has proven that Magnelis® has a much more stable behaviour and much better resistance against corrosion compared with traditional zinc coatings. The French Corrosion Institute confirmed in December 2021 that Magnelis® behaves 3.8 times better than galvanised steel.

Magnelis® behaviour in soils extensively tested

Atmospheric corrosion of metals has been studied extensively for years. However, for structure parts in soil, corrosion mechanisms are more complex and corrosion categories cannot be defined in the same way. There are also fewer norms and standards regarding soil corrosivity, as well as less literature and data.

Nevertheless, engineers need to reduce this uncertainty and evaluate the lifetime of their solar structures, be they exposed to harsh atmospheric conditions or rammed in soil.

To achieve this, ArcelorMittal has developed a deep knowledge of the behaviour of Magnelis® in soils through accelerated laboratory and outdoor tests, internally and in collaboration with external research centres such as the French Corrosion Institute.

Different types of soils - clay, silt, and sandy - with different corrosivity levels (evaluated using the German standard DIN 50929-3: 2018) have been used for these tests.

The results, after several years, confirm the improved resistance of Magnelis® vs galvanised steel: the rate of corrosion of Magnelis® increases at a lower rate and with less dispersion of the results.

High performance in soil validated

In December 2021, The French Corrosion Institute assessed the performance of Magnelis® in soil and concluded that, in the tested soils range, the average corrosion resistance of Magnelis® in soils was improved by an average factor of 3.8 compared to continuous hot dip zinc coating. This factor has been calculated based on mass loss according to the ISO 8407 standard.

Depending on soil analysis, Magnelis® ZM430 (35 µm per side) or ZM620 (50 µm per side) are the minimal coatings to be used.

The durability of rammed poles can be guaranteed by ArcelorMittal on a project basis, provided that physical, chemical, and electrical soil analyses have been performed.

Text:
ArcelorMittal Europe - Flat Products

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ArcelorMittal Europe - Flat Products