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Phosphorus grain boundary segregation

The thermodynamic enrichment of phosphorus atoms at the interfaces of former austenite grains. This lowers the cohesive energy and leads to intergranular brittle fracture susceptibility.

Phosphorus migrates to the grain boundaries during cooling and makes the structure brittle there. The risk of cracking increases, especially when the weld is heavily stressed. You need to control the cooling and not cool down too fast. Also make sure the material is clean so that not much phosphorus gets into the weld pool in the first place.

MetallurgieSchweißtechnik

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