Question

Why do both these molten metals round in a crucible?

Answer 1

✔✔❤In one of my classes this past semester, we did a casting lab. In this lab we used an induction furnace which uses a coil to generate heat within the material.



✔✔❤ One of the things that I noticed, was that inside the furnace, the material seemed to form a near half sphere at the bottom of the crucible.





✔✔❤This occurred for both molten Al-Si-Mg alloy and a low carbon steel. If we were to compare that to water which is known to have a high surface tension, it was drastically more rounded that what water in the crucible would have been.




✔✔❤My question is why. Is it the induced magnetic field carrying the material towards the center and upwards? Or is it that both molten materials have an incredibly high surface tension? If it has to do with surface tension,



why do these metals have a high surface tension? My understanding of the chemical bonding in metals would imply to me that they shouldn't have that. Any help on answering this is appreciated.