Globular Solidification Structure
Globular solidification structure is a fine-grained, equiaxed microstructure with high nucleation rates and strong undercooling of the melt. It improves the isotropic mechanical properties of the component.
Physicochemical Mechanism of Action
The globular solidification structure forms through rapid cooling of the melt, where many small grains solidify simultaneously. This results in a fine-grained microstructure with homogeneous properties in all directions.
Metallurgical Relevance & Welding Risks
This structure improves mechanical properties such as strength and toughness, as it allows for uniform distribution of stress across the entire microstructure. However, too rapid undercooling can lead to porosity and lack of density, which in turn reduces mechanical properties.
Workshop Practice & Action Guidelines
To achieve a globular solidification structure, it is important to cool the melt as quickly as possible. This can be achieved through high cooling rates, e.g., by using cooling water or special cooling gases. The optimal cooling time depends on the material used and the desired structure, but generally it should be between 10 and 30 seconds.