Surface tension coefficient
The surface tension coefficient indicates how strongly a liquid relates to other liquids or solids. A high value means strong tensions and can lead to porosity.
Physical-Chemical Mechanism of Action
The surface tension coefficient (σ) is a measure that describes the tension resistance between two liquids or between a liquid and a solid. It is expressed in newtons per meter (N/m). The higher the coefficient, the stronger the tensions at the surface.
Metallurgical Relevance & Welding Risks
A high surface tension coefficient can lead to increased porosity. This happens because the tensions impede the movement of gases and liquids through the structure. In high-quality weld joints, it is important to minimize these tensions to produce a defect-free joint.
Workshop Practice & Instructions
To reduce porosity, you can lower the surface tension coefficient by choosing the right weld pool or by adding deoxidizers. A typical goal is to keep the coefficient as low as possible to ensure a clean and tight joint.