Ferrite stabilizer
A ferrite stabilizer such as chromium or molybdenum prevents austenite structure and promotes ferrite formation in multi-phase steels. This increases hardness and toughness but reduces formability.
Physicochemical mechanism of action
Ferrite stabilizers such as chromium or molybdenum bind oxygen in the molten phase. This prevents austenite structure and promotes ferrite formation. The body-centered cubic lattice remains stable, which increases hardness and toughness.
Metallurgical relevance & welding risks
An excessive amount of ferrite stabilizers can make the structure too hard and reduce formability. This leads to increased susceptibility to cracking and coarser grain during cooling. With incorrect welding parameters (too fast cooling), glass-hard, crack-prone structural constituents form.
Workshop practice & actionable instructions
Use ferrite stabilizers in filler metal selection for steels with high hardness and toughness requirements. Ensure correct cooling rate (t8/5 between 10 and 20 seconds) to achieve a balanced structure. If cooling is too fast, the structure can become too hard, leading to cracks.