Epistaxis
Epitaxial solidification is a process where new crystals grow on existing phase boundaries or inhomogeneities. This affects the kinetics of transformation and precipitation processes.
Physical-Chemical Mechanism of Action
Epistaxis is a crystallization process where new crystals grow on existing phase boundaries or inhomogeneities. This process is favored by the attractive forces between the atoms of the new phase and the existing phase boundaries.
Metallurgical Relevance & Risks in Welding
Epistaxis can lead to uneven grain formation, which can impair the mechanical properties of the material. It increases susceptibility to cracks and alters the microstructure by introducing new phases or structures.
Workshop Practice & Instructions
To minimize Epistaxis, controlled cooling time and temperature should be maintained during heat treatment. For steels with high carbon content, it is particularly important not to keep the cooling time too short or too long to avoid glass-hard martensite formation.