The heat-up curve: why the first few days decide years of service life

The complete relining is finished — and now begins the phase that decides years of service life: the controlled heat-up.

Why this step is so critical

• Once set, refractory castable contains both free and chemically bound water. Heating up too quickly generates steam pressure inside the structure — the risk ranges from spalling to destruction of the new lining before the furnace has ever produced anything.
• Every plant is started up along a material-specific heat-up curve: defined heating rates and holding stages in the critical temperature windows in which the moisture escapes in a controlled way. Depending on the material and wall thickness, this takes two to five days.
• The process is monitored by temperature measurement and fully documented — the curve actually followed forms part of the as-built documentation and is the basis for the 12-month warranty.