Rapid and cost effective melting and processing of reactive metals (e.g. Titanium, Zirconium and their alloys), super clean superalloys and other metals requiring low inclusion content can be provided by Consarc with the Induction Skull melting furnace system.
ISM: The Process
ISM is a method of melting metals in a segmented, water-cooled copper vessel, under vacuum or controlled atmosphere in an induction coil. This is done metal-to-metal, without a refractory lining. The copper crucible is made up of water-cooled segments or "fingers". The magnetic field produced by the coil, in effect, passes through the crucible to induce heat in the metal charge causing it to melt. The field also intensively stirs the liquid metal pool. A thin layer of metal remains frozen against the bottom of the crucible forming a skull. The low velocity boundary layer in the liquid adjacent to the skull, together with the skull itself and the interface (joint) between the skull and the crucible all serve as thermal resistances, reducing the heat conducted from the hot liquid into the cold crucible.
When the crucible, the coil, the frequency and the power level are all properly designed and matched, the sides of the liquid metal pool are pushed inwards, away from the interior side walls of the crucible. In effect, the sides of the pool are supported magnetically. The absence of physical contact with the side walls prevents the crucible segments from electrical shorting and further reduces the heat loss into the crucible. The process is most often used in casting with top or bottom pouring but it can also be used in ingot production. In this case, open-bottomed crucibles with a drawn down starter plug are used to slowly form an ingot from top fed charge material.
Consarc can supply economical single chamber batch systems, twin chamber batch systems for higher productivity or multi-chamber designs with automated materials for high production and / or unique material handling constraints.
Induction Power Equipment
Power is supplied from a solid state Inductotherm induction power supply specifically designed to the correct supply the correct power and frequency for the ISM process. It is taken through the vacuum chamber by means of a sealed water-cooled coaxial rotary power feedthrough or power port assembly to the melting coil.
Static or Centrifugal Casting
Tilt pouring of the metal from the ISM crucible is a rapid process and moulds can be pouredin a static or centrifugal casting configuration. Centrifugal casting turntable systems are designed by Consarc to integrate into the chamber design for ease of mould handling.
All Consarc ISM installations are supplied with a fully integrated PLC and the option for PC SCADA based control systems for safe and efficient operation of the furnace. Remote control operation is also recommended for reactive metal melting and casting.