Localized Austenite Network
A continuous network of retained austenite along grain boundaries in incompletely transformed steels or cast materials. This network can cause toughness and hardness issues.
Physical-Chemical Mechanism of Action
In the melting process, some of the metal in certain steels or cast materials remains in the austenitic structure. This retained austenite forms a network along the grain boundaries that has not fully transformed to ferrite.
Metallurgical Relevance & Risks in Welding
The localized austenite network can increase the toughness and hardness of the weld. It leads to increased susceptibility to hot cracking and can unevenly alter the microstructure, resulting in stress buildup and further defects.
Workshop Practice & Instructions
To minimize the risk of hot cracks and toughness issues, it is important to precisely control melting times and temperatures. For steels with high austenite content, a slow cooling method should be used (t8/5 > 25 s) to ensure the network fully transforms. Use special welding consumables or processes that suit these metals if needed.