Super duplex nitrogen alloying effect
The targeted addition of nitrogen to the austenite alloy increases corrosion resistance and improves mechanical strength in the weld zone.
Physical-Chemical Mechanism of Action
Nitrogen is incorporated into the metal as an interstitial element, which stabilizes the austenite structure. This prevents the phase transformation to martensite and coarsens the grain, which improves the corrosion protection layer.
Metallurgical Relevance & Welding Risks
The addition of nitrogen increases corrosion resistance in crevices and reduces the loss of mechanical strength in the weld zone. However, incorrect doses can lead to phase transformations, which can affect hardness and toughness.
Workshop Practice & Instructions
For superduplex steel, use a nitrogen content of 0.1 to 0.3 %. Ensure correct welding temperature and adequate post-treatment for strengthening. A too high dose of nitrogen can lead to phase transformations, which can affect hardness and toughness.