Bonding Zone
The fusion zone is the area between the base material and the weld metal where metals exchange. This process improves strength and microstructure.
Physicochemical Action Mechanism
The fusion zone forms by the exchange of atoms between the base material and weld metal. During welding, metals from both materials diffuse into each other, leading to a homogenous bond.
Metallurgical Relevance & Welding Risks
An uneven fusion zone can lead to weak spots and cracks. Too little diffusion can cause poor bonding between the weld and base material, leading to tearing and hot cracks. Too much diffusion can coarsen the microstructure and reduce strength.
Workshop Practice & Procedures
To achieve a good fusion zone, the welding process must be carefully controlled. Temperatures should be set to allow sufficient diffusion without coarsening the microstructure. Optimal cooling time is crucial for a homogenous bond.