TL;DR
Roof refractory wear around the electrode ports reduces the protective barrier and risks a burn-through. Inspect the roof at every planned stop and track minimum thickness against the replacement threshold.
What you might see
- roof delta temperature rising faster than normal
- visible erosion at the electrode ports on the roof
- scrap metal splash marks on the roof refractory
- roof cooling water return temperature higher than normal
Likely causes
Arc radiation and splash eroding the refractory around the electrode ports over service life
Scrap or slag splash impacting the roof during charging or heating
Operating with the electrodes too close to the bath surface increasing roof exposure
Cooling water flow below specification in water-cooled roof panels adjacent to the hot zone
Required tools
- IR thermometer for roof surface temperature
- Refractory thickness probe or ultrasonic gauge
- Roof maintenance log
Safety first
- Ladle furnace roof is extremely hot after operation. Verify surface temperature before any approach.
- Molten steel splash hazard from the ladle below during roof positioning. Keep clear of the ladle during roof handling.
- High-voltage electrode circuit. Isolate the transformer before any work near electrode ports.
Procedure
- 1
After each planned stop, visually inspect the ladle furnace roof when the ladle is at the parking position and the roof is in the inspection position.
Warning: Inspect only when the roof is cold. Ladle furnace roofs retain extreme heat after a heat sequence. Verify the surface temperature with an IR thermometer before approaching. - 2
Measure the refractory thickness at the electrode ports and the center of the roof using a calibrated probe or an ultrasonic thickness gauge.[1]
- 3
Record the measurements in the roof maintenance log. Track the trend against the minimum allowable thickness.[1]
- 4
If the refractory at any port is below the minimum, schedule a roof reline at the next available planned stop.
- 5
Check the water-cooled roof panel flow rates and return water temperatures. Low flow or high return temperature indicates a blocked cooling panel.
- 6
Before reinstalling the roof, confirm all electrode port tiles are intact and seated correctly.
Sources
Danieli Danieli LF Ladle Furnace / AOD / VOD general technical documentation, Danieli
Danieli ladle furnace refractory inspection and maintenance documentation (general)
More guides for Danieli Danieli LF
How to diagnose electrode arc instability on a Danieli LF ladle furnace
Arc instability is most often caused by a worn or broken electrode, or contact arm current path deterioration. Inspect the electrode condition and the contact shoe contact before adjusting any controller parameter.
How to diagnose and clear a ladle bottom plug clog on a Danieli LF
No argon stirring with the valve open means the bottom plug is blocked by solidified steel. Test the plug with a high-pressure purge before labeling it failed; blocked plugs often clear with a brief pressure pulse.
Stop fixing the same fault twice.
Dovient turns guides like this into your team's shared playbook, with AI that catches recurring issues before they break the line.