Rust Conversion
Rust conversion is a chemical treatment that transforms existing iron oxides on steel into stable, insoluble complexes with reactive primers. This prevents underfilm corrosion of the subsequent coating.
Physico-chemical mechanism of action
Rust conversion is a process where existing iron oxides on steel are converted into stable, insoluble complexes using reactive primers. The primer reacts chemically with the iron oxides and forms a layer that prevents further rusting.
Metallurgical relevance & risks in welding
Rust conversion is especially important in welding to prevent corrosion damage. Without this treatment, the steel can continue to rust after welding and reduce the service life of components. A faulty rust conversion process can lead to incomplete conversion or over-conversion, which in turn causes undercutting of the subsequent paint and contaminates the weld.
Workshop practice & instructions
For successful rust conversion, it is important that the steel is cleaned thoroughly before painting. Apply the primer to a thickness of 20-30 µm and let it dry for at least 15 minutes. After conversion, treat the steel with a suitable paint within 4 hours to create the protective layer.