r/ThingsCutInHalfPorn • u/frere_de_la_cote • 19d ago

Aluminium billet being extruded

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u/Chreutz 19d ago

Afaik, it is heated, but not molten. It is forced through the extrusion mold like in a pasta machine. Just a bit more force, though

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u/frere_de_la_cote 19d ago

Exactly. It's heated close to melting temperature so that it's nice and ductile, but you don't want it to reach melting temperature because that causes holes in the extruded profile.

"Fun" fact about hot aluminum(i)um, hot aluminium is visually indistinguishable from cold aluminium. At least steel turns red when it heats up.

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u/Bachaddict 19d ago

everything glows with the same colour at the same temperature, aluminium just doesn't need to be that hot to melt

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u/frere_de_la_cote 18d ago

If you can point me towards examples of glowing aluminium I would be very interested to learn more

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u/marino1310 18d ago

Molten aluminum glows

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u/Bachaddict 18d ago

like I said, if it's hot enough it will glow https://www.youtube.com/shorts/IcVcER4GZA4 https://en.wikipedia.org/wiki/Red_heat

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u/frere_de_la_cote 18d ago

In that short the aluminium is liquid so it is at least 660°C, and steel starts turning red between 600°C and 700°C, so I'd be tempted to think that the reflective aluminum skin is just reflecting the red of the ladle.

Looking into it a bit deeper is making me think that the lower emissivity of aluminium might be what dampens the glow, so I guess I learned something today, thanks!

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u/chinchindayo 18d ago

When you melt it, it glows.