Molybdenum Pitting Resistance Equivalent
The molybdenum pitting resistance factor describes the improvement of pitting resistance by molybdenum in corrosive, chloride-containing media for high-alloy steels. It increases the service life and reliability of the material.
Physical-chemical mechanism of action
Molybdenum reduces the number of chloride ions on the steel surface, which slows down the corrosion reaction. It forms a dense layer on the surface that interrupts contact between the steel and corrosive media.
Metallurgical relevance & welding risks
Too high a molybdenum content can lead to increased hardness and reduced formability, making the weld more difficult. There is also a risk of hot cracking if cooling is too fast.
Workshop practice & action instructions
Use molybdenum in filler materials only in the specified amount (usually 0.1 to 0.5 %). Make sure the weld cools slowly and in a controlled manner to avoid hot cracking. Monitor the corrosion of the material regularly and adjust the filler content accordingly.