Intercrystalline segregation phase
Intergranular segregation phase is a local enrichment of companion elements at grain boundaries during solidification, which increases the tendency for hot cracks or brittle fracture.
Physical-chemical mechanism of action
During cooling of metals, local enrichments of companion elements occur at grain boundaries. These segregation phases can form in various structures such as martensite or Widmanstätten.
Metallurgical relevance & risks during welding
These phases make the weld particularly brittle and prone to hot cracking. They can arise from too rapid cooling or uneven solidification, affecting the strength and toughness of the weld.
Workshop practice & instructions
To avoid intergranular segregation phases, it is important to ensure controlled cooling. This can be achieved by using shielding gases or with the use of cooling water. For highly brittle steels, the critical temperature window (t8/5) should be kept between 10 and 20 seconds to achieve uniform solidification.