View Single Post
  #27  
Old 09-07-2009, 05:26 PM
Brian Gingras
Guest
 
Posts: n/a
Quote:
Originally Posted by David Hopman View Post
That's strange, because you'd think that with the ends of the elements sticking out of the back of the furnace, that at some place on them there would be a temp of 1200. I guess the lowered overall temp moves that 1200 point from the solid part to the spiral part and allows a crack. Taking the elements down to room temp doesn't seem to cause problems- 3 of mine have been cycled 5 times already with no issues.

Come to think of it, I used to lower the glory hole to 1590 at night. Stopped doing that because of some issues with the superstructure, but the elements seemed unaffected. Did that for at least a couple of years.

no spiral, these are solid bar type TW. the word from engineering was that the 1200F exposure for long enough will cuase the breaks. And since these would sit for a week or more at that point they were getting stressed. When running the temps fluctuate and move around, same thing when charging. Keeping the furnace static at 1750F, with this particular furnace causes the elements to develop micro fractures 5" inside the walls of the furnace.
Reply With Quote