Vacuum Induction Melting & Strip-casting Furnace

Selection criteria

Vacuum / Ar protection, wheel speed, pouring temperature.

Supply chain

Strip-casting (vacuum induction melting) furnaces for NdFeB come mainly from Japanese makers such as ULVAC and from Shenyang, which is China's centre for magnet vacuum furnaces. Furnace capability underpins magnet consistency, which is one reason established magnet makers outperform small shops.

Buyer FAQ

What does good strip-cast flake look like?

Good flake is typically about 0.2–0.4 mm thick, with fine columnar Nd2Fe14B grains, an evenly distributed Nd-rich phase and no free α-Fe dendrites. Thickness and microstructure depend on wheel speed and pouring temperature. Ask magnet suppliers whether they check flake metallography and α-Fe content for each heat.

Why has strip casting replaced ingot (book-mould) casting?

Slow-cooled ingots form coarse grains and soft-magnetic α-Fe that must be removed by long homogenising anneals. Strip casting cools fast enough to suppress α-Fe, so alloys can run closer to stoichiometry with less rare earth and give finer, more uniform powder later. A supplier still using ingot casting for sintered grades is a quality concern.

What should I ask a magnet supplier about alloy melting?

Ask whether alloy is melted in house or bought in, the furnace batch size (production furnaces commonly melt several hundred kilograms per heat), and how composition is verified, for example by ICP analysis per heat. Confirm traceability from heat number to finished magnet lot, which you will need if a Br or Hcj problem appears.

Where it is used