Levitation Melting Facility KTS
The Levitation Melting Facility “KTS“ is a multifunctional apparatus for alloying and casting of sensitive metallic rods using a levitated melt in a cold crucible. Avoidance of contamination by non-metallic inclusions is often crucial for the production of castings and feed rods of susceptible inter-metallic compounds. These inclusions are usually oxide phases which are often formed by reactions between the metallic melt, the crucible material and/or the surrounding atmosphere. A method to prevent this contamination is the levitation melting method. Therefor, a powerful high frequency generator (40 kW to 60 kW, up to 100 kHz) induces strong eddy currents in the metallic sample and in a copper crucible. Emerging repulsive magnetic fields cause electrodynamic suspension and magnetic levitation of the sample above the crucible. While the sample material melts due to resistive heating, the crucible is actively cooled and remains at low temperatures. A fast-moving water-cooled coquille stick is used to pull casting rods out of the levitated melt into a quartz tube recipient. Thereafter, the sample material is in a "shell" of of its own composition and does not come into contact with the wall of the crucible. The resulting rods have diameters of 6 mm or 8 mm and a length of approx. 10 cm, depending on the used crucible. Furthermore, the melting can be carried out under high vacuum up to 10-5 mbar or within an inert gas atmosphere. The vacuum is generated by a pumping unit with integrated turbo-molecular pump. The alternating electromagnetic field ensures a thorough mixing of different components in the levitated melt. The cold crucible is adjustable in the z-axis relative to the coil for an easy installation and removal of the crucible. The generator and the coil have a separate cooling circuit to prevent overheating. A high-resolution CCD camera ensures the visual observation of the process, whereat the sample temperature is measured permanently with a two-color pyrometer. All system parameters are controllable via a comfortable GUI and processed by a PLC unit. The KTS device enables the user to carry out several processes like cleaning metallic precursors by casting, pre-alloy materials and to cast the final material shaped as a rod for crystal growth.
High frequency induction system
- Generator power options: 40 kW to 60 kW
- External resonant circuits unit
- Frequency range: 20 kHz to 100 kHz
- External induction coil: inner diameter: 80 mm, length: 50 mm
Process tube and atmosphere
- Gas-sealed process chamber
- Vacuum: 10-5 mbar, better vacuum possible on request
- Sensitive vacuum sensor
- Turbo pump system close to the process chamber, wide diameter connections
- Gases: Ar, optionally oxygen-reduced Ar
- Many other gases possible on request, e.g. Ar/O2, Ar/H2, CO/CO2
- Active titanium getter argon cleaning (optional, removes O2 traces in argon down to 10-12 ppm)
- Oxygen content measurement system (optional)
Crucible and chill-mold
- Water-cooled copper crucible
- Adjustable in the z-axis relative to the coil for an easy installation and removal
- Inner diameter of the permanent chill-mold : 6 mm or 8 mm (optional), bigger on request
- Fast-moving water-cooled coquille stick for casting rod pulling
- Quartz tube recipient
- Sample/melt mass: up to 100 g
Process control and monitoring
- All system parameters are visible and adjustable via a comfortable GUI on a 27" touch screen
- Process control and monitoring data are processed by a programmable logic controller
- Two-color pyrometer with several temperature ranges
- High-resolution CCD camera with specialized lenses and filters for direct crucible and melt monitoring
- Monitoring application: video recordings, snapshots and length measurements, zoom function, permanent simultaneous temperature recording
- Different video and image file formats selectable
- Power ramp functions
- Safety system with protection housing, door lock system, automatic shut down function
Required laboratory connections
- Energy supply: 3 phase AC, 50 Hz, 400 V, 3x60 A
- Gas supply
- Cooling water supply
- Height: 195 cm
- Width: 88 cm
- Depth: 103 cm
- More compact dimensions easily possible on request
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