ALUMINIUM MELTING
- The increased thermal resistance of oxide coated particle of Aluminium is the chief reason why they are difficult to melt in furnace operated on the principle of radiation, convection and conduction. This difficulty is overcomes by induction
- As the emissivity factor of Aluminium is very low, heat given to the path through surface or the surface load is very low, but the induction surface rating is more than 3 times thanothers.
- Because of the stirring actions there is uniform temperature throughout the bath in Induction heating.
- In fuel fired or electric furnaces the bath temperature is uneven and vary from 500 C to 750C, because of this melting loss and gas absorption is very high but it is very low in Induction because of stirring action.
- Another advantage of electro magnetic stirring is that in many case the ingredients of high melting point like Copper or Nickel can be dissolved directly thus eliminating the use
- The hydrogen ‘ofcourse’ is not present or produced on the gaseous covering of the bath contained , in Induction furnaces as it is a cold top. The hydrogen absorption in the path is eliminated.
The most of the users of the Induction furnace in the foundry report that they are not using the fluxes and they have found only one half the degassing agent to be necessary as compared with other furnaces. The reverberatory furnace of good condition can rarely prevent the melting loss of much less than 5% and a crucible furnace of tilting variety is ranged between 2-3% while the melting loss is of 0.8% in Induction
BRASS *
- The precision alloying is possible by directly adding the elements.
- The zinc loss is minimum
- The metal loss is less than 1% compared to 5% in fuel fired furnaces. The high Frequency furnaces melts hard materials of Tungstan-Cromium-Carbide group and which can be casted in form moulds as a temperature of 2000 to 2300 C.
GALVANIZING INDUCTION FURNACE *
- The Induction melting unity provides an entirely new approach with refractory container of essentially unlimited life which do not in any way contribute to the formation of dross from job.
- The galvanizer will agree however that 10% can be gained by elimination of iron kettle and at least 10% by perfect temperature control.
VACUUM INDUCTION FURNACE *
- One of the main characterised of vacuum melt alloys are their consistent properties e.g. vacuum melted copper is practically free from volatile impurities, and better than of h.c. copper.
- Low carbon content of less than 0.005% is possible in vacuum Induction melting. This is better than are melting.
- Vacuum melted magnetic materials give better performances than by any other process.
- It is easier to control boron in vacuum Induction melted alloys. only 15 ppm of boron in waspaloy doubles the rapture life.
- The vacuum melted bronze could be brazed where as the other is not.
- The vacuum melted bronze could be brazed where as the other is not.
- The vacuum melting of ‘cleanliness’ alloys (52100) gives a marked increase in bearing life.
- It is used for production of finished castings by lost wax investment process to increases both titanium and aluminium content in Nickel base alloys and there-by achieve high temperature strengthening associated with the precipitation –hardening elements.
ZONE REFINING *
- Induction heating is ideal method of heating. This gives a very short zone than any other process.
- Induction Heater is preferred in floating zone technique, zone leveling, crystal pulling and levitation.
- The stirring action of Induction melting increase the efficiency of the zone refiner.
