Macroscopic Ingot Segregation
Macrosegregation is the uneven distribution of alloying elements in an ingot. It occurs due to convection currents and shrinkage during solidification.
Physical-Chemical Mechanism of Action
During solidification of a casting, natural convection currents and shrinkage effects occur. These move the alloying elements unevenly within the material, leading to an uneven distribution.
Metallurgical Relevance & Risks in Welding
Macrosegregation can lead to uneven strength and toughness within the block. This increases susceptibility to cracking and hot cracking, especially in highly stressed areas.
Workshop Practice & Action Guidelines
To minimize macrosegregation, during welding production:
• Ensure uniform thermal conductivity of the block.
• Perform the solidification steps slowly and in a controlled manner.
• If necessary, a homogeneous alloy can be improved by adding filler materials.