Permanent Magnet Heaters for Aluminum Billets HEH (High-Efficiency Heater)

Aluminum billets are always pre-heated at a temperature between 400°C ÷ 500°C prior to being extruded in the extrusion press. During the years, the OEMs of this industry have developed/adopted various pre-heating technologies such as:

- Heating the billet by gas fired furnaces. Such pre-heating method is affected by low efficiency (40% ÷ 45%) and CO2 emission.
- Heating the billet by inductors. The magnetic field is generated by water-cooled coils and the heating efficiency does not exceed 55%.
GMS/ENGITEC has tailored a new high-efficiency heater for billets based on the principle of permanent magnet called HEH, standing for “High Efficiency Heater”.
The system – PATENTED – is based on a series of permanent magnets which rotate around the billet that undergoes the pre-heating process.

The complete heating system is composed of several rotors independent from each other so that one can set the best heating profile for each Alloy and/or billet diameter.

HEH technology is the best solution for both tapered heating profiles or for isothermal heating profiles. When compared with traditional systems available, HEH gives the following major advantages:

- High and repeatable precision of heating ramp of the billet.
- Electrical efficiency rate - 80-85%.
- Electric energy saving - at least 30%.
- Low maintenance costs.
- There are no cooling water circuits, converters, capacitor banks.

Thanks to the limited size and to its modularity, the HEH is particularly suitable to be installed on existing presses also in combination with existing gas heating systems.


A 3D sketch of the HEH system; in the top right corner, a view of the HEH in operation at Pandolfo (Italy).