FAQs: Induction Furnaces

How should I charge my induction furnace and what charge material should I use?

All material being charged into the induction furnace must be completely dry and care should be taken so that the charge continues to feed into the furnace properly. If the charge hangs up due to interlocking or bridging, the metal below can superheat and erode the refractory, causing molten metal to penetrate to the coil. Automated charging systems should be used whenever possible because they significantly enhance safety by permitting furnaces to be charged remotely, keeping the foundry worker at a distance or behind protective barriers. Charge materials such as enclosed containers, propane tanks, gas cylinders, shock absorbers, aerosol cans, sheared tubing or pipe, and similar materials must never be charged into a furnace.

What is the difference between a coreless furnace and a channel furnace?

In a coreless induction furnace, the entire bath functions as the induction heating area. A copper coil encircles a layer of refractory material and a powerful electric current travels through the coils cre­ating a magnetic field that penetrates the refractory and quickly melts the metal charge material inside the furnace. In a channel furnace, induction heating takes place in the “channel,” a relatively small and narrow area at the bottom of the bath. The channel passes through a laminated steel core and around the coil assembly. The electric circuit is completed when the channel is filled with molten metal. Hotter metal leaving the channel circulates upward, raising the temperature of the entire bath. Foundries typically use channel furnaces to hold and dispense molten metal whenever it is needed.

I noticed that you have a wide variety of furnaces. What are the differences and how do I know which one is right for me?

We manufacture a variety of coreless induction furnaces (i.e., Heavy Steel Shell Furnaces, Small Steel Shell Furnaces, Dura-Line Furnaces, Rollover Furnaces and Mini-Melt Furnaces) as well as Crucible-type furnaces (i.e., Acutrak Furnaces, Lift-Swing Furnaces and Push-Out Furnaces) so that, regardless of the size or application of your molten metal needs, we can customize a system for you. From small capacity, precision casting operations to the largest induction melting foundry, we have the right furnace for you.

How often should I re-line my furnace?

It’s best to refer to the refractory manufacturer/supplier for their recommendations on selection, installation, sintering and maintenance of the refractory. They will have the most current information on the specifications and performance characteristics of your specific material.

Can I use any type of refractory/crucible for a new application?

You must contact your refractory provider and completely understand the type of refractory and how it will be affected by your particular application. Contact the induction furnace supplier as well to make certain the refractories being considered are compatible with the design of the equipment.

Does Inductotherm offer vacuum furnaces?

Inductotherm is the principal supplier of induction furnaces and power supplies to the world’s leading vacuum system manufacturers and precision investment casters, alloy manufacturers and anyone needing the highest quality molten metal. Inductotherm Vacuum Furnaces are designed specifically for operation in high vacuum environments and include vacuum-adapted construction methods and the industry’s most advanced coil and connector dielectric insulation technologies and procedures.

What is the difference between air and vacuum melting furnaces?

Virtually every type of Inductotherm induction furnace can be used for both air, controlled atmosphere or vacuum melting. However, the coil and furnace itself are often designed specifically for operation in high vacuum environments and include vacuum-adapted construction methods and the industry’s most advanced coil and connector dielectric insulation technologies and procedures to ensure optimum performance.

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