Are you experiencing elevated thermocouple temperatures in your hearth lining?

Has your furnace been stopped, or started, recently?

Have you detected and/or corrected a water leak that may have found its way to the hearth lining?

Or, maybe you just have a short maintenance outage scheduled in the near future.

With fluctuations in temperatures for any reason, refractory linings undergo a certain amount of movement. How much movement is dependent on the amount of heat and the Coefficient of Thermal Expansion (CTE) of that specific material. It is then that the differential movement of two adjacent materials most likely results in separation of the lining from the essential cooling. Once separated from the cooling element, the hot face temperature may rise above the solidification temperature of the process/slag and thermal attack on the lining commences.

For these reasons GrafTech recommends installing our GR37™ Grout. This is a resin bonded two-component carbonaceous material containing a special graphite flake that expands at temperatures above 200° C. The fine, flour-like, particle sizing of the powder component, when mixed with the furfuryl alcohol-based liquid component and mechanically pumped, either by hand or machine, allows this material to flow into extremely thin gaps of less than 1 mm thickness. The residual heat in the lining is sufficient to cure the mixture and reinstate contact between the refractory lining and the cooling element. Shortly after using GR37 grout, thermocouple readings of the lining temperatures should return to normal.