Crack limit modification
Microalloying steels with elements like niobium or vanadium increases the tear resistance and improves crack resistance. This prevents cracks and boosts mechanical strength.
Physical-chemical mechanism of action
Doping steels with microalloying elements like niobium or vanadium leads to a finer grain structure. These alloy into the weld zone and form more stable phases that increase crack resistance.
Metallurgical relevance & risks in welding
Insufficient doping can lead to low crack resistance and cause cracks. Overdoped material can lead to increased hardness and possible hot cracks.
Workshop practice & action instructions
Doping with niobium or vanadium in a content of 0.1 to 0.3 % is common. When welding, watch for controlled cooling to get the desired grain structure. For highly stressed applications, use filler rods with a higher microalloying element content.