Ferrite
Ferrite is a soft, malleable, and magnetic crystal structure of iron with low carbon content. It forms on slow cooling and has higher toughness than austenite.
Physicochemical mechanism of action
Ferrite is a crystal structure of iron that is soft and malleable at room temperature. It consists of a microscopic lattice that forms during slow cooling in the weld pool. Ferrite can only dissolve very small amounts of carbon.
Metallurgical relevance & risks in welding
Ferrite has higher toughness and better formability than austenite, making it suitable for many applications. However, ferrite is prone to hot cracking on fast cooling because it can become glass-hard. This can lead to damage.
Workshop practice & instructions
To avoid ferrite in the weld and increase toughness, ensure slow cooling in the weld pool. This can be achieved by controlling the cooling rate, e.g., by using a cooling water system or applying cooling jackets.