Complexing Agent for Trace Elements
Trace element scavengers are additives that convert unwanted impurity elements into stable compounds, preventing them from moving freely and adsorbing at grain boundaries. This stabilizes the microstructure and increases toughness.
Physical-chemical mechanism of action
Trace element scavengers react with unwanted impurities such as oxygen or sulfur to form stable compounds. These compounds have lower mobility and reduce adsorption at grain boundaries, which stabilizes the microstructure.
Metallurgical relevance and risks in welding
Without scavengers, unwanted impurities can move freely and segregate to grain boundaries. This can cause porosity, reduced toughness, and increased susceptibility to cracking and hot cracking. Using scavengers stabilizes the microstructure, increases toughness, and improves weld quality.
Workshop practice and procedures
Add scavengers to the weld pool to stabilize unwanted impurities. The exact dosage depends on the material and the desired effect. For steels with high oxygen content, a scavenger content of 0.1-0.2% may be necessary. Optimize melting temperature and cooling rate to achieve the desired microstructure.