Component segregation coefficient
The component segregation coefficient indicates how much a metal coarsens during cooling and which elements accumulate and in what concentration.
Physical-chemical mechanism of action
The component segregation coefficient (Sk) describes how much a metal coarsens during cooling and which elements accumulate and in what concentration. It is the ratio of the concentration of an alloying element in the solid state to that in the liquid state at equilibrium.
Metallurgical relevance and risks in welding
A high segregation coefficient leads to strong coarsening and non-uniform element distribution. This can cause cracks, fractures, or reduced mechanical properties of the weld. As the segregation coefficient increases, the risk of hot cracks and porosity also increases.
Workshop practice and procedures
To minimize segregation, controlled cooling is essential. This can be achieved by choosing the right welding process (e.g., TIG welding) and the correct cooling time. For highly segregating alloys, slow cooling is recommended to avoid coarsening.