A member of AMG Advanced Metallurgical Group, N.V.

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Vacuum Investment Casting (VIM-IC)

Liquid Metal Cooling for DS/SC Solidification

For the production of large directionally solidified (DS) and single crystal (SC) components high thermal gradients are required. In order to provide the highest temperature gradient and a flat solidification front, ALD’s patented “central baffle with heat sink” may be applied. The “central baffle with heat sink” provides an improved thermal environment during solidification of particularly large DS/SC components.

in large view

in large view

1. Vacuum precision casting furnace with central water-cooled heat sink and central baffle (patented), 2. Schematic presentation of the LMC process with improved baffle technique (patented)

A further improvement of the solidification conditions for large DS/SC components is provided by the liquid metal cooling (LMC) process. In the LMC process, the mold is immersed for solidification of the components into a liquid cooling bath, either consisting of aluminum or tin. The heat extraction from the component is based on heat conduction and convection, which is remarkably better than the radiation heat extraction of the conventional DS/SC process. Larger temperature gradients are especially important for the production of large DS/SC parts, e.g., for turbine blades and vanes for stationary gas turbines.

ALD has built several LMC furnaces for R & D and pilot production of directionally solidified and single crystal structures by the LMC process with tin as well as with aluminum as cooling agent.

In total, ALD has built more than 100 vacuum precision casting furnaces for customers all around the world and the largest mold heater (48” x 60” / 1,200 mm x 1,500 mm) ever used for the production of DS/SC components.

in large view

in large view

1. Vacuum investment casting furnace, type ISP 10 DS/SC/LMC, for the production of large DS/SC parts by
the LMC process