Magnetohydrodynamic flow
Magnetohydrodynamic flows occur when electrically conductive liquids like molten metal move in a magnetic field. The field induces a current, which in turn strengthens the field and affects the movement.
Physical-Chemical Mechanism of Action
Electrically conductive liquids like molten metal can be moved in a magnetic field. This process generates a current that in turn amplifies the magnetic field and influences the motion. The flows are determined by the Lorentz force acting between the electric current and the magnetic field.
Metallurgical Relevance & Risks in Welding
Magneto-hydrodynamic flows can cause uneven distribution in the weld pool. This can lead to porosity, inconsistencies, and reduced mechanical properties of the weld. Furthermore, the flow can disturb the thermal balance and cause certain chemical reactions to proceed unevenly.
Workshop Practice & Action Points
To minimize magneto-hydrodynamic flows, the following measures should be taken: Use a homogeneous magnetic field and control the current intensity. Ensure the molten metal is evenly distributed and no uneven flows develop. If needed, magnetic field shields can be used to influence the field.