A channel furnace on aluminum zinc alloy, where zinc vapor and buildup shorten every inductor campaign.
Aluminum zinc alloys attack an inductor channel two ways, through the metal and through the vapor.
A fired loop gives both less to work with
This case covers a CeraLoop inductor lining in a channel furnace melting aluminum zinc alloy. The loop is a precast, fully fired ceramic insert that forms the metal channel, so the inductor starts without a form to burn or melt out, and its dense, non-wetting surface resists the zinc penetration and buildup that shorten conventional rammed or cast channels.
In a conventional inductor the channel is formed around a template that is burned or melted out, often a metal form of the same alloy family. The refractory around it is sintered with the first heats, and its porosity decides how much metal and vapor can get in.
Zinc bearing alloys are hard on that lining. Zinc vapor can travel through the refractory, saturate it and in the worst case create a ground fault. Highly fluid metal wets an underfired lining, and aluminum oxides build up in the channel until it clogs. Each of these ends the campaign early.
A rammed channel only becomes a lining after it has been sintered in service, so its porosity is highest exactly when the zinc first arrives, and a loop that is fired before installation skips that window.
A CeraLoop, cast and fired by Blasch in a ceramic grade chosen for the alloy, set into the inductor box and backed with a dry vibratable or castable. The loop is held in place while the backup is rammed in from the bottom, around the sides and up to the top, with the usual forms and vibration tools.
In a galvalume melting test of the custom high alumina material used for these loops, Blasch found little to no metal penetration and minimal oxidation.
A brass foundry with zinc vapor problems documented its CeraLoop campaigns in detail. CeraLoop in a brass foundry
Fired ceramic loops for channel induction furnaces, distributed by Allied Mineral Products.
Ladles, degassers, riser tubes and linings for aluminum and zinc.
Zinc vaporizes at melt temperatures, travels through porous refractory and saturates it. In severe cases it reaches the coil side and causes a ground fault.
A dry vibratable or castable from Allied Mineral Products fills the space between the loop and the inductor box.
No form has to be burned or melted out, and no wash heat is needed. The furnace can start on the alloy it runs.
Tell us the inductor model, the alloy and what ends a campaign today. A Blasch engineer checks whether a fired loop fits your furnace.
