Austenite stabilizer
Austenite stabilizers such as nickel or manganese prevent the formation of martensitic phases during cooling by stabilizing the face-centered cubic lattice of iron and extending the high-temperature austenite range to lower temperatures.
Physical-Chemical Mechanism of Action
Austenite stabilizers like nickel or manganese reduce the energy required for the transition of iron to the martensitic lattice. They bond to the iron atoms and alter the crystal structure, making the martensite formation path energetically less favorable.
Metallurgical Relevance & Welding Risks
Without austenite stabilizers, the iron structure forms martensitic phases during rapid cooling, leading to high stresses and crack-prone microstructures. This can cause hot cracks and low weld toughness. Using austenite stabilizers slows down the cooling, allowing for a more stable and tougher microstructure.
Workshop Practice & Instructions
Use alloys with austenite stabilizers in welding processes with rapid cooling. Ensure that the weld cools down slowly and in a controlled manner to avoid martensite formation. When using nickel or manganese in the alloy, pay attention to the correct dosage, as too much can lead to high stresses.