Melting Furnace & Degassing Unit

Selection criteria

Melt temperature, rotary degassing, density index.

Supply chain

Melting furnaces and rotary degassing units are mostly supplied by Chinese foundry-equipment makers, with international brands for high-end foundries. Ask die casters for density-index or reduced-pressure test records.

Buyer FAQ

What is the density index and what value should I require?

The density index compares a melt sample solidified under reduced pressure (about 80 mbar) with one solidified in air; more hydrogen gives a larger difference. A well-degassed die-casting melt typically shows a density index of about 1–3 %, and leak-tight housings often specify 2 % or less. Ask for readings both after degassing and at the casting machine.

How are melting and rotary degassing typically set up for die casting?

Central gas-fired tower (shaft) furnaces melt ingot and returns efficiently, and holding furnaces at each machine keep ADC12 or A380 at roughly 640–680 °C. Rotary degassing with nitrogen or argon usually runs 5–15 minutes per ladle with a graphite rotor at several hundred r/min. Flux treatment and drossing remove oxides.

What are common pitfalls with degassing?

Degassing removes gas porosity but cannot fix shrinkage porosity from poor die or gating design. Hydrogen is picked up again if treated melt is held too long, especially in humid weather. Graphite rotors and shafts wear and need regular replacement, and final porosity should still be checked by X-ray or leak testing of castings.

Where it is used