Melting Point of Aluminium and Its Alloys

Pure aluminium melts at about 660 °C — far lower than steel (about 1,400–1,500 °C) or copper (about 1,085 °C). This low melting point makes melting and casting aluminium relatively inexpensive and recycling it economical.

Alloys do not have a single melting point

Unlike the pure metal, aluminium alloys melt and solidify over a temperature range: between the “solidus” (where melting starts) and the “liquidus” (where it is complete). Alloying elements usually bring this range below 660 °C.

Aluminium–silicon alloys

In the aluminium–silicon system, the eutectic point lies at about 12.6% silicon and about 577 °C. Alloys close to this composition, such as LM6 and A413, solidify at an almost constant temperature and have excellent fluidity. Alloys such as A356, with about 7% silicon, have a wider freezing range.

Casting temperature

For casting, molten aluminium is usually held a little above the liquidus so that it flows well; the exact temperature depends on the alloy, the casting process and the section thickness. Excessive temperatures increase hydrogen pick-up and oxidation, so temperature control goes hand in hand with melt degassing.

Compared with other metals

Almas alloy ingots are made for remelting in foundry furnaces. See the grade composition table.