Induction heating for extrusion IAS/SMS Elotherm
IAS is the worldwide market and technology leader for precision heating of billets for extrusion presses. Along with billet heating, the core activities of IAS are melting and casting of non-ferrous and ferrous metals. All this is consistently based on clean induction technology.
Induction heating for extrusion: tailored and highly efficient
Correct heating of the material to be extruded is crucial for the extrusion process. IAS has therefore developed the ExtruLine series of induction heating machines specifically tailored to that end. Precisely matched to the materials to be processed, such as aluminium or copper and their alloys as well as steel and iron alloys or special materials such as titanium, zirconium, molybdenum or magnesium alloys, the IAS machines ensure precise and above all reproducible billet temperatures.
In the induction heating process, the metal is exposed to an alternating electromagnetic field generated by a current-carrying coil. This non-contact process produces eddy currents in the material, which in turn produce heat. This process can be influenced in a controlled manner by adjusting the frequency and power. As the billets are not heated by heat transfer as in a conventional furnace, heating times in the IAS machines are very short and the temperature can be set precisely.
All machines in the ExtruLine series have a modular structure, allowing individual configuration requirements to be fulfilled effectively at all times and enabling seamless integration into existing production lines. The system is designed to be so flexible that it can be used for base heating of billets in combination with an upstream gas furnace or as a stand-alone solution.
Direct, precise heating with the TEM-PRO heater
The TEM-PRO heater is a temperature profile heating system. It enables precise temperature control with extrusion presses, thereby ensuring a perfect production process with isothermal extrusion presses. Thanks to its high transferable power density, the TEM-PRO heater offers distinctly higher performance than a gas furnace, especially with large billet dimensions. Furthermore, there is no risk of overheating the billet surface. The TEM-PRO heater achieves a high efficiency of up to 75%, depending on the input material.
The TEM-PRO heater can be used in combination with a conventional furnace to establish a temperature profile in billets preheated in the furnace, or operated as a stand-alone unit. The productivity of the entire pressing line is significantly boosted by the standardised link to tools for isothermal extrusion presses.
Using the TEM-PRO heater in a smart hybrid system
In many cases, a gas furnace alone is no longer sufficient to meet current requirements for temperature control in modern aluminium extrusion presses. In cooperation with extrutec, IAS has developed a patented inline heater for extrusion lines based on the TEM-PRO heater concept. The resulting compact system solution can be integrated into an existing extrusion line, even with very tight space constraints.
The inline system consists of a gas furnace with various heating zones and a directly connected, multi-zone induction furnace. The rod is first heated in the gas furnace and then brought to the desired final temperature in the induction furnace, taking into account the precise temperature profile of the billet to be cut off. The rod is then cut to the required billet length by a saw or shears before the extrusion process.
This innovative combination provides optimal energy utilisation with highly precise temperature control. Any desired axial temperature gradient (taper) is possible. This leads to a significantly more productive extrusion process with consistently high quality of the extruded products. Furthermore, it avoids an undesirable temperature distribution in the workpiece that could lead to process disruptions. Thanks to these advantages, plant operators can quickly recover the cost of the TEM-PRO heater (fast ROI).
Ideal temperature range not only for extruded stainless steel tubes
IAS has developed advanced induction machine concepts specifically for seamless high-alloy steel tubes manufactured using the extrusion process. With complex stainless steels, the extrusion temperature must be kept within very tight limits. This requirement is met, as well as the demand of operators to be able to profitably produce small production batches with various geometries from special alloys. High cost-effectiveness, flexibility, energy efficiency, short set-up times and reliable process control are especially impressive features of these IAS concepts. In this way IAS fashions intelligent combinations of gas furnaces and induction heating to utilise the advantages of both types of heating, matched to the product spectrum and process technology. The following combinations have proven their worth in practice:
- Horizontal induction base heating with vertical induction final heating
- Gas-fired rotary furnace with reducing atmosphere and vertical induction post-heating
- For relatively small billet dimensions up to 180 mm and operation without a piercing press, horizontal induction preheaters
- Gas preheating up to about 700°C with induction intermediate heating and post-heating
By using a multi-zone induction heating coil in post-heating as well as the possibility of frequency adjustment and continuously adjustable power control with IGBT converters, the temperature profile is managed for process reliability and kept within tight temperature limits. Electrical efficiency up to 81% can be achieved, depending on the configuration, or even up to 83% with titanium alloys.
New ideas for proven technology
Resistance and induction heating machines from IAS for multi-part extrusion dies round out the product portfolio for extrusion press operators and are amongst the proven technologies for temperature controlled applications in the extrusion sector.
They enable variable control of power and zone heating in accordance with the requirements of modern extrusion presses. Furthermore, preheating stations, breach heaters for indirect extrusion and ram heaters can be implemented with this technology. The heating systems are equipped with a quick-change fixture.
The Container Overheat Prevention (COP) cartridge from IAS is a heating cartridge solution with significantly improved overheat protection. This innovation eliminates the critical problem of overheating in the heating rod bore. Existing resistance heaters can easily be upgraded with COP cartridges without any changes to the dies.