Phase Transformation Kinetics
Phase transformation kinetics describes how metals transform from one crystal structure to another and which factors influence the speed.
Physicochemical mechanism of action
Phase transition kinetics refer to the transition from one crystal structure to another through diffusion or nucleation. This process is temperature-dependent and can be influenced by the speed of diffusion processes.
Metallurgical relevance & risks in welding
Incorrect phase transition kinetics can lead to uneven stresses, cracks, or missing properties. For example, too fast cooling can lead to a glass-hard structure (martensite), which increases hardness but reduces toughness.
Workshop practice & action instructions
To ensure optimal phase transition, it is important to precisely control the cooling steps. This includes holding the weld at a specific temperature for a specific time (t8/5). For steels with high carbon content, the cooling steps should be slow to ensure sufficient austenite. For lower carbon content, a faster cooling process may be appropriate.