Oak Ridge National Laboratory (ORNL) has introduced both tungsten halogen based and plasma arc based radiant heating to a variety of non-conventional applications. This has been accomplished through design modifications to insure lamp survivability. The IPC presently has seven different tungsten halogen based systems varying from 0.500 watts to 300,000 watts as well as three different plasma based systems from 1.2 kW to 3.5 kW. Immediate benefits of radiant processing include fast heating and cooling, precise temperature controlling, instantaneous starting and stopping, and low operating costs. The emissive power can be delivered effectively with over 90% efficiency (t-3 lamp) to a wide variety of part sizes and geometries.
Infrared furnaces rely on electromagnetic radiation as a mechanism for transferring heat energy. As opposed to conductive and convective heating, radiant heating does not rely on the transfer of heat through directly contacting systems, nor does not rely on the utilization of an enclosed, intermediary gas medium to transmit thermal energy from a source to a workpiece. Radiant heating does not require any medium for transmission, and as a result, any type of processing atmosphere, including vacuum, may be used.
Because of the cold wall nature of the majority of these furnaces, the highly controllable heat fluxes involved result in rapid heating i.e. 50-400°C/sec, depending on the material composition and geometry of the workpiece. Precise controllability ensures that zone heating, to produce a desired temperature profile, is a practical and achievable process. These high heat fluxes provided by the heating method can be delivered unidirectionally over large areas allowing control of temperature gradients through thick sections of material. In fact, these furnaces have been shown to be robust enough to preheat dies in a hammer forge shop for nearly one year without lamp failure.
Joining applications such as advanced materials joining, titanium aluminide, iron aluminide, titanium matrix composites, automotive parts, titanium to steel for armor applications, and others all stand to benefit from the salient features mentioned above. Other applications include unidirectional heating of die blocks for rapid preheat, preferential tempering, predetermined hardening, and preheat for powder metallurgical sheet, steel, and wire. In the many cases mentioned, the infrared processing technique results in tremendous cost savings through reduced processing time, reduced operating cost, and environmental friendliness.
In the News:
- Infrared Theory (coming soon!)
- KomTek Letter (PDF)
- ORNL Review Article
- Science and Technology Highlights (PDF)
Recent Talks: NEW!
- "Infrared Transient-Liquid-Phase Coating of Materials"
- "Low Cost Processing of Titanium Aluminide Composites and Advanced Sheet Materials"
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- Materials Processing Science and Technology Section
- Metals and Ceramics Division
