Microstructural Banding
Microstructural Banding is a banding of different metal structures in the weld, caused by segregation of alloying elements during cooling.
Physical-Chemical Mechanism of Action
During primary solidification in welding, the metal forms different crystal structures depending on alloying elements and cooling rate. These different structures build up as bands or rows.
Metallurgical Relevance & Risks in Welding
Microstructural Banding can lead to increased hardness and toughness, improving mechanical properties. However, it can also cause stress buildup leading to cracks or wear issues. Additionally, it can make welding of heavy alloys more difficult.
Workshop Practice & Instructions
To minimize Microstructural Banding, control the cooling rate and use the correct alloy. For heavy metals, use special welding processes like gas welding or TIG welding with low voltage. If needed, post-weld heat treatment (PWHT) can be applied to homogenize the structure.