Macrosegregation
Macrosegregation is the uneven distribution of alloying elements or impurities over a large part of a component. It occurs due to slow cooling and leads to varying material properties.
Physical-Chemical Mechanism of Action
Macrosegregation occurs when a metal cools over a long period. During solidification, alloying elements or impurities can concentrate in certain areas and build up. This leads to an uneven distribution profile.
Metallurgical Relevance & Welding Risks
Macrosegregation can lead to uneven stress buildup and varying strength within a component. This increases the risk of cracks and distortion, especially under mechanical load. In welded joints, it can cause inconsistency in hardness and stress state of the weld.
Workshop Practice & Action Items
To avoid macrosegregation, cool the metal as quickly as possible after welding. You can use cooling water or air flow. For long solidification times, ensure homogeneous cooling to achieve even distribution of alloying elements and impurities.