Sulfur grain boundary segregation

Physicochemical Mechanism of Action

Sulfur atoms attach to grain boundaries and improve the bonds in the lattice. This leads to higher cohesion strength.

Metallurgical Relevance & Welding Risks

Sulfur segregation can prevent hot cracks by stabilizing the crystal lattice. However, excessive segregation can lead to higher hardness and lower formability, which makes later machining harder.

Workshop Practice & Instructions

To promote sulfur segregation, you can slightly raise the melt temperature or use special segregation gases. The optimal sulfur content should be between 0.1% and 0.3%. Watch the cooling curve carefully to avoid hot cracks.