Where does the outstanding flow length come from in Rheocasting?

Let’s use an everyday use case to explain it. Everybody knows the warm feeling of pocket warmers on cold winter days. You press the metal plate, and the liquid crystallizes. It keeps your hand warm for 20 to 30 minutes.

When the aggregate changes from liquid to solid, the energy level changes. A liquid has more energy at the same temperature. That excess energy, called latent heat, is distributed in the surrounding area.

Suppose we look at a cast part. In classical liquid HPDC, a solid metal layer forms on the outer surface towards the tool. The heat is transferred through the solidified material into the steel. In Rheocasting, that surface layer forms the same way.

But then the magic happens. The next solidification steps occur within the melt. While making the slurry, globular solid phases are produced. The solidification happens in these spheres, too. The only direction the latent heat can go is back into the melt, so the remaining liquid parts are heated by the latent heat.

That is ideal for long flow lengths. Imagine a gigacasting. A flow length of 2 to 3 meters is typical for such parts. A liquid cools down quickly; in the end, melt fronts cannot recombine because they are too cold. With Rheocasting, they arrive hotter and can still be fed from the gate. This effect will drastically improve the quality of your gigacasting.

This effect of the long flow length enables smaller ingates and a reduced projected area. That allows for smaller die-casting machines in Rheocasting than liquid HPDC. See the Rheocasting Expert on Demand for more information about the support you can get to start with Rheocasting.