Microscopic Segregation Line
Microscopic segregation lines are one-dimensional concentrations of impurity elements along solidification paths or deformation lines. They cause local differences in mechanical properties.
Physical-chemical mechanism of action
Microscopic segregation lines are formed by the concentrated enrichment of accompanying elements such as silicon or carbon along solidification paths or deformation lines. These concentration enrichments affect the local microstructure and the mechanical properties of the material.
Metallurgical relevance & risks in welding
Segregation lines can lead to increased hardness and grain size in the weld, which impairs toughness and dimensional stability. They increase the risk of cracks and hot cracking, especially when they are located near stress concentration points.
Workshop practice & action guidelines
To minimize the effects of segregation lines, it is important to carefully select the welding material and processes. For highly stressed applications, special welding methods such as gas tungsten arc welding (GTAW) or plasma welding should be used to ensure homogeneous deformation and solidification. The hardness of the weld should be checked by ultrasonic testing to ensure that it is within the acceptable range.