Chill casting aluminum vehicle parts

What is a chill mold?

Coquille - is the split mold for reuse. The term comes from the French word coquille - shell, sink, shell. In English technical literature, this method is called gravity die casting., which better reflects the essence of the process, namely, filling the mold – mold – the melt occurs only under the influence of gravity of the melt itself without any external influence, as, for example, in casting methods under low or high pressure.

Aluminum die casting

aluminum casting The chill mold is one of the standard processes in the production of complex automotive parts. This method is a proven and highly accurate technology for mass production of large batches of products.. It is used in the so-called carousel automatic casting systems.. The demountable mold provides optimal heat removal from the hardened castings., which reduces the casting time. The result is castings with good mechanical properties, especially after additional heat treatment (figures 1, 2 and 3).

karusel-lityo-v-kokilFigure 1 - Carousel aluminum die casting system

lityo-v-kokil-golovka-bloka-cilindrovFigure 2 - Aluminum car cylinder head,
chill cast

lityo-v-kokil-blok-cilindrovFigure 3 – Aluminum cylinder block car VW-Lupo,
chill cast

Chill casting technology

In chill casting technology, the aluminum melt is subjected to the necessary metallurgical processing (degassing, modifications, settling) in the so-called holding oven, which is usually located next to the foundry machine.

The melt in quantity for one casting is served in a special ladle and poured from it into the gating system of the mold. The melt smoothly fills all mold cavities, starting from the bottom and until, until molten metal appears in profitable extensions, which are located in the upper part of the mold (figure 4).

In figures 4 and 5 cylinder head casting shown. The speed of filling the mold and the solidification conditions is affected by the design of the gating system for supplying the melt and profitable extensions.

texnologiya-litya-v-kokilFigure 4 – Chill casting technology diagram

lityo-v-kokilFigure 5 – The technological process of casting in a chill mold

Source: European Aluminum Association, 2011