Interfacial tension of the melt
The force at the boundary between liquid metal and solid surrounding material, which determines wetting behavior. It affects porosity and cracking during welding.
Physicochemical mechanism of action
The interfacial tension is the force acting at the phase boundary between liquid metal and solid surrounding material (such as steel or gas). It influences the wetting behavior of the metal through the tension that occurs between the two phases.
Metallurgical relevance & welding risks
High interfacial tension can lead to poor wetting and thus to pore formation. This can impair the strength of the weld and cause cracks. A low tension level can improve wetting behavior, but too low tension can also lead to poor melting behavior.
Workshop practice & instructions
To achieve optimal interfacial tension, it is important to precisely control the melting time and temperatures as well as the wetting medium. High tension can be achieved with a clean metal and a suitable gas shield. If there are problems with porosity, it should be checked whether the interfacial tension is too high and, if necessary, the melting parameters should be adjusted.