Weld Pool Stability
Melt pool stability is the balance of forces that hold the molten metal and prevent it from running out or falling through.
Physicochemical mechanism of action
Melt pool stability results from the stress field between the solid workpiece surface and the liquid melt. Surface forces, such as stress and tensile force, hold the melt on the workpiece surface. Additionally, electrical forces and thermodynamic stresses act.
Metallurgical relevance & risks in welding
Insufficient melt pool stability leads to runout or fall-through of the melt, resulting in porosity and lack of fill in the weld. This can lead to fracture points and reduction of the mechanical properties of the overall weld joint.
Workshop practice & action guidelines
To ensure melt pool stability, the melt pool should be regularly cleaned. The content of deoxidizers such as silicon or titanium must be controlled. The temperature of the melt pool should be kept stable to ensure a uniform melt and optimal fill of the weld.