Casting in ASRC
At WMG we have a range of casting equipment enabling us to produce casts of bespoke compositions and/or to investigate effects of changes in casting conditions on the microstructure and properties of the material. The facilities comprise:
1. A 10 kg vacuum induction melting (VIM) furnace which offers the capability to make bespoke alloys. The 10 kg casts are a perfect level for our PhD students and for alloy development studies and subsequent rolling and characterisation. The high vacuum levels (10-6 mbar) ensures high cleanliness. The VIM also includes an auxiliary charge chamber which allows for repeated sampling and additions, allowing systematic compositional studies to be carried out in one session.
2. 1 kg Topcast induction melter, which can melt steel in < 4mins under an argon blanket. This method of melting gives us the best interaction with the molten product and thus can be instrumented with thermal imaging cameras etc. as well as the liquid steel being poured into more specifically designed moulds.
For studies that look into segregation and the influence of solidification rate, then wedge moulds are used. By varying the mould thickness top and bottom be can achieve cooling rates from 100 down to 1 °C/s, thus drastically varying the secondary dendrite arm spacing, segregation and back diffusion.
3. Two addition furnaces also allow studies for casting, particularly for the study of slow cooling rates. The Carbolite bottom loading and top loading furnaces have peak temperature of 1700°C and 1100°C respectively which can be used for solidification trials of either steel or aluminium at cooling rate <10°C/min.
4. We also have a range of equipment to look at solidification and casting on a very small scale. One such piece of equipment is a droplet furnace. By locally heating the tip of a small rod, beads of liquid can be formed inside a highly controlled atmospheric chamber. The droplet (once large enough) falls from the rod and onto a substrate, where the heat transfer coefficients can be extracted using embedded thermocouples, non-contact dual colour pyrometer and high speed thermal imaging cameras. This process can be used to simulate the fast interactions involved in 3D printing as well as laser cladding processes.