Planar Solidification Front
A smooth phase boundary between solid and liquid metal that occurs during slow cooling or with pure metals. It prevents macrosegregation.
Physicochemical Mechanism of Action
The planar solidification front forms in a slowly cooling metal sample, where the solid and liquid phases lie against each other in a clear, smooth transition. This process typically occurs in pure metals or very slow cooling rates.
Metallurgical Relevance & Welding Risks
The planar solidification front is important for weld quality because it prevents macrosegregation. This segregation can lead to brittleness and cracks. However, rapid cooling can create an irregular phase boundary, damaging the structure and reducing strength.
Workshop Practice & Procedures
To ensure a planar solidification front, cooling after welding should be slow. This can be achieved by using a cooling wall or controlling the ambient temperature. For steels with high carbon content, it's especially important that cooling is controlled and not too fast to get a smooth phase boundary.