Refractory technology2 min
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.
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.
Whoever saves two days during start-up pays for them several times over later — with shorter campaigns and unplanned shutdowns. A properly executed heat-up curve is the cheapest lifespan insurance there is.
At a glance
2–5 days
duration of a controlled first heat-up
Documented
heat-up curve as part of the as-built documentation
Further reading
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